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S3 BIOLOGY HOLIDAY PACKAGE

EXCRETION AND OSMOREGULATION..

EXCRETION AND OSMOREGULATION

Excretion is the removal of waste products of metabolism from the body. Most of the waste

products are toxic when allowed to accumulate in the body.

Importance of excretion

To remove toxic waste products whose accumulation in the body poisons/harms the

organisms.

To remove excess materials in the body which when left to accumulate affects the body

metabolism.

Excretory products are divided into two groups i.e.

1. Nitrogenous excretory products.

These are excretory products, which contain the element nitrogen. They include ammonia, urea

and uric acid.

Ammonia:

This is a highly toxic nitrogenous waste and it requires a lot of water for its elimination. It is very

soluble in water and due to this it requires less energy to be excreted. Ammonia is excreted by

organisms which live in fresh water and therefore have a lot of water in their bodies. Such

organisms include bony fish, protozoans, and amphibians when in water,

Urea:

This is a less toxic nitrogenous waste. It requires less water for its excretion. It however requires

a lot of energy for its excretion because of its low solubility in water compared to ammonia. Urea

is excreted by terrestrial organisms, which have easy access to water, and marine organisms.

Such organisms include terrestrial mammals, amphibians when on land, cartilaginous fish, etc.

Uric acid:

This is less toxic than urea and requires no water for its elimination from the body. It is insoluble

in water. The demerit of excreting uric acid is that it requires a lot of energy for its excretion.

Uric acid is excreted by birds, reptiles and insects and also common in desert animals.

2. Non nitrogenous excretory products.

These are excretory substances that do not contain the element nitrogen. Such products include

Carbondioxide, water, excess salts and excess water.

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A table showing examples of organisms, their excretory products, their excretory organs

and their habitats

Example of

organism

Excretory product Excretory organ Habitat

Bony fish Ammonia Kidney Flesh water

Cartilaginous fish Urea Kidney Marine water

Reptiles Uric acid Kidney Terrestrial

Birds Uric acid Kidney Terrestrial

Tadpoles Ammonia Gills Flesh water

Adult amphibians Ammonia Kidney Flesh water

Urea Terrestrial

Mammals Urea Kidney Terrestrial

Insects Uric acid Malpighian tubules Terrestrial

Animals producing nitrogenous compounds in form of urea are those living on land but have

easy access to water. This is because though urea is less toxic than ammonia, it needs a relatively

high amount of water to reduce its toxicity to the body during excretion. Urea is excreted in form

of urine, which is a mixture of urea, salts and water. Urea is excreted by mammals, amphibians

when on land and marine vertebrates.

Animals producing nitrogenous wastes in form of uric acid are those living on land with little

access to water. Uric acid is the least toxic and needs the least amount of water for its excretion.

Such animals conserve their water because it is not lost during excretion. These animals include,

bird, reptiles and insects.

Excretory organs

These are organs that release excretory products. They include the following.

Table showing excretory organs and their corresponding excretory products

Excretory organ Excretory product

Lungs Carbondioxide and water

Liver Bile pigments

Kidney Urea, excess salts and excess water

Malpighian tubules Uric acid

Skin Excess water, excess salts and some urea

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EXCRETION IN MAN

In man the excretory organs are the kidneys, skin and lungs. Their excretory waste products are

as shown in the table below.

Excretory organ Excretory product Excretory substance

Skin Sweat Urea, excess salts and excess

water

Lungs Exhaled air Carbondioxide and water

Kidney Urine Urea, excess salts and excess

water.

THE KIDNEY AND THE EXCRETORY SYSTEM

Structure of urinary system

Parts and functions of the urinary system

1. Aorta

It carries oxygenated blood with all food nutrients to the kidney.

2. Renal artery:

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This arises from dorsal aorta. It brings blood containing excretory products to the kidney.

3. Renal vein:

It carries filtered blood from the kidney to the posterior vena cava.

4. Ureter:

These are two narrow tubes arising from hilum of each kidney. They connect the kidneys to the

urinary bladder. They transport urine to the urinary bladder.

5. Urinary bladder:

It is a thick walled elastic sac-like structure which stores urine.

6. Sphincter muscle:

These muscles are elastic thus can contract and relax to control urine flow.

7. Urethra:

It is a passage for urine to the outside of the body.

THE KIDNEY

Structure of the kidney

The kidneys are solid bean-shaped structures and they occur in pairs in mammals. They are

reddish-brown in colour enclosed in a transparent membrane and attached to the back of the

abdominal cavity.

The kidney tissue consists of many capillaries and renal tubules connected together by

connective tissue. The kidney has two major parts.

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1. The cortex which is a dark outer part. It consists of the Bowman’s capsule which is

responsible for ultra-filtration of blood passing across it.

2. The medulla, which is a lighter inner, part. It is made up of many cone-shaped portions called

pyramids.

The pelvis is the area where the ureter leaves the kidney.

The kidney performs three major functions in the body.

1. It carries out excretion.

2. It carries out the function of osmoregulation.

3. It contains endocrine glands, which secrete hormones.

The kidney is made up of several microscopic structures (functional units) called nephrons where

the actual excretion and osmoregulation takes place.

THE NEPHRONE

This is the functional unit of the kidney. It carries out the function of excretion and

osmoregulation in the kidney.

The nephron consists of a cup-shaped structure known as the bowmans’ capsule. Blood comes

to the nephrone through the afferent vessel, which is a branch of the renal artery, and it leaves

through the efferent vessel.

The efferent vessel joins many other efferent vessels from other nephrones to form the renal

vein.

In the bowmans’ capsule the afferent vessel divides to form capillaries. The capillaries are highly

coiled and they form a knot called glomerulus.

Leading from the bowmans’ capsule is a highly coiled tube known as proximal convoluted

tubule. This is continuous with a U shaped tubule called loop of Henle.

The loop is divided into the descending loop and ascending loop.

From the loop of Henle the tube becomes highly coiled to form the distal convoluted tubule

which leads to the collecting duct.

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Structure of the nephron

Parts of nephron

1. Bowman’s capsule:

It contains a dense-network of capillaries called glomerulus. The glomerulus is formed from the

wider arteriole of renal artery called afferent arteriole. It is located in the cortex.

The Bowman’s capsule serves the function of filtering small molecules in blood such as urea

glucose, etc. through a process called ultra-filtration.

Adaptations of the glomerulus to ultra-filtration

Collecting duct

Distal convoluted tubule

Descending loop of Henle

Ascending loop of Henle

Proximal convoluted tubule

Glomerulus

Bowman’s capsule

Capsular space

Afferent vessel from renal artery

Efferent vessel to renal vein

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1. Having high blood pressure that forces small molecules out of the glomerulus. This is due to

the afferent arteriole being wider than the efferent.

2. Having many capillaries that gives it a large surface area for ultra-filtration.

3. Having a semi permeable membrane that can allow any small molecule to pass through.

Adaptations of the bowman’s capsule to collect the filtrate

1. Possession of cup-shaped structure which enables it to collect the filtrate.

2. Having a porous upper membrane that easily allows filtration.

3. Having a large volume that can accommodate more filtrate.

2. Proximal convoluted tubule:

This is a site where re-absorption of useful materials such as glucose and some small amino acids

and water from glomerular filtrate back to blood takes place.

3. Loop of Henle:

It’s made up of a descending (going down) limb and an ascending (going up) limb. The main

function of the loop of Henle is to make the tissue fluid in the medulla more concentrated than

the glomerular filtrate in the nephron so that water needed in the body is reabsorbed. It’s

known to cause the retention of water. This is one way of conserving water in camel because of

its extremely long loop of Henle.

4. Distal convoluted tubule:

It chiefly re-absorbs salts like chloride ions together with water, leaving a concentrated liquid

now called urine which passes down to collecting ducts.

5. Collecting duct:

This duct carries urine from the distal tubule to the pelvis of kidney. It allows outward movement

of water thus conserving it.

Adaptations of the nephron to re absorption

1. Having a thin membrane (one cell thick) to reduce the diffusion distance of materials.

2. Having micro villi to increase the surface area for re absorption.

3. Having numerous mitochondria to provide energy for active reabsorption.

URINE FORMATION

The process of urine formation takes place in the nephrone. It occurs in two phases.

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1. Ultra-filtration.

2. Selective re-absorption.

Ultra filtration

Blood comes from the afferent vessel into the glomerulus at high pressure because the afferent

vessel is larger than the efferent vessel. (This implies that more blood enters the nephrone than

that which leaves). This pressure forces small molecules to filter out of the blood capillaries into

the glomerulus to form the glomerular filtrate. Blood in the renal artery contains proteins, red

blood cells, white blood cells, urea, water, salts, amino acids and vitamins.

At the glomerulus, small molecules filter out by ultra filtration to form the

glomerularfiltrate. This filtrate contains glucose, urea, water, salts and vitamins.

Proteins and blood cells do not filter out because they have bigger molecules, which cannot pass

through the walls of the glomerulus.

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The filtrate formed moves from the Bowman’s capsule through the capsular space to proximal

convoluted tubule where selective reabsorption starts to occur.

Selective reabsorption

In the proximal convoluted tubule:

Glomerulus

Afferent arteriole

Efferent arteriole

Bowman’s capsule

Glomerular filtrate flowing to proximal convoluted tubule

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Most of the food materials are re absorbed into the blood capillaries by active transport e.g. all

the glucose, vitamins, some salts like sodium chloride and even some water is re absorbed by

diffusion.

In the loop of Henle:

As the filtrate flows down the descending limb, water is reabsorbed back into the capillaries by

osmosis leading to increased concentration of the filtrate down the descending limb.

As the filtrate ascends, the thick ascending limb of loop of Henle, salts like Na and K are

reabsorbed by active transport. This leads to a decrease in concentration of the glomerular filtrate

in the ascending limb.

In the distal convoluted tubule:

Selective re absorption of salts by diffusion occurs. Water is also osmotically reabsorbed.

In the collecting duct:

Water is lost to the highly concentrated medulla tissues by osmosis from which later the

remaining filtrate is urine which goes via the ureter and temporarily stored in the urinary

bladder.

Summary of the steps involved in formation of urine in the kidneys

Name Process Examples of molecules

Ultra-filtration

(pressure filtration)

High blood pressure forces small

molecules from the glomerulus into

bowman’s capsule.

Water, glucose, amino acids,

salts, urea, uric acid,

creatinine.

Selective

reabsorption

Diffusion and active transport return

molecules to blood at the proximal

convoluted tubule.

Glucose, water, salts and

amino acids.

Tubular secretion Active transport moves molecules from

blood into the distal convoluted tubules.

Uric acid, creatinine,

ammonia and hydrogen ions.

Reabsorption Along the length of the nephron and

notably at the loop of Henle and

collecting duct, water returns by osmosis

following active reabsorption of salts.

Water and salts.

Excretion Urine formation rids body of metabolic

wastes

Water, salts, urea, uric acid,

ammonia.

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Comparison of substances in blood and urine

Nitrogenous waste In blood In urine

Urea 0.03 2.0

Proteins 7-9 0

Glucose 0.1 0

Chloride ions 0.37 0.6

Sodium ions 0.32 0.35

Water 93 95

There are proteins in blood and there is none in urine because proteins are not filtered out of the

blood vessels into the glomerulus due to the large size of their molecules.

Urea is more in urine than in blood because it is filtered out of blood and it is not reabsorbed

back in the blood.

Water is more in urine than in blood because it is used to dissolve urea.

However the relative amounts of water in urine and in blood varies depending on the amount of

water in the body, amount of solutes in the body, temperature and body activity.

There is glucose in blood and no glucose in urine because glucose is reabsorbed from the

glomerular filtrate back into the blood.

Salts like chlorides and sodium ions are more in urine than in blood. This is because they are in

excess and they are not reabsorbed back into the blood. Because of this they tend to concentrate

in urine.

EXCRETION IN PLANTS

Plants excrete less poisonous waste products like CO2 through the stomata and acids through

dropping leaves and fruits. Plants do not require specialized excretory organs due to;

1. Plants can store excess proteins unlike in mammals.

2. They accumulate less metabolic wastes due to their low metabolic rate.

3. Plants synthesize their organic food substances according to their requirements. This ensures

that no excess is made.

4. Plants do not produce nitrogenous waste products. They produce non-nitrogenous wastes,

which are less toxic to their bodies.

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5. Some wastes accumulate in particular parts of the plant and they are eliminated when this

part of the plant falls off.

6. Some of the wastes are useful in other processes within the plants body. For example Carbon

dioxide produced from respiration can be used in photosynthesis.

7. They do not locomote and they are less metabolically active than animals.

HOMEOSTASIS

This is the maintenance of a constant internal environment of the body. The internal environment

of the body is composed of tissue fluids, which surround cells. Homeostasis involves controlling

the blood sugar level, salt level, water level, temperature and Carbon dioxide concentration.

WATER BALANCE AND OSMOREGULATION IN MAN.

This is the maintenance of a constant amount of water in the body.

The water level is kept neither high nor low but within a limit according to the demands of the

body. The level is maintained by loss of excess and gain if more is required.

Water is lost from the body through urine, sweat, expiration, and feaces during egestion and it

can be gained through; drinking eating and water from metabolism.

However, the loss and gain of water brings about changes in blood concentration.

These changes are detected in the brain by the hypothalamus.

If the blood passing through the brain is too concentrated, the hypothalamus stimulates the

anterior lobe of the pituitary gland to secrete a hormone called antidiuretic hormone (ADH) into

the blood stream. When the hormone reaches the kidneys, it causes the walls of the nephrones

(distal convoluted tubules and collecting ducts) to become permeable to water and water is

reabsorbed from the glomerular filtrate back into the blood. The urine that is secreted becomes

more concentrated and yellowish in colour. This reduces the loss of water in urine.

If blood passing through the hypothalamus is too dilute, the hypothalamus is not stimulated and

the production of ADH from the pituitary gland stops and the nephrones become less permeable

to water. Less water is therefore reabsorbed from the glomerular filtrate resulting into production

of colourless urine in big volumes. This mostly happens during cold conditions where water loss

through sweating is minimal.

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When conditions are hot, sweating increases, lowering the water level in blood. This causes more

re-absorption of water in the nephrones resulting in production of concentrated pale yellow urine.

Because of the high concentration, when urine is poured on grass or any plant, they get scotched

because the cells lose water to the surrounding concentrated urine and the plant cells become

flaccid. This brings about wilting and drying of the plant.

When the level of water in blood is too low the hormone causes a feeling of thirst, which makes

one to drink water in order to bring back the normal water level in blood.

Failure of organisms to secrete ADH leads to constant urination of large amounts of dilute urine

thus increases the blood concentration, a condition known as DIABETS INSPIDUS.

Excretion and osmoregulation in other animals.

The amoeba

Amoeba excretes excess water by use of a contractile vacuole. The contractile vacuole is a small

sac-like structure lying inside the cytoplasm.

The cell membrane surrounding amoeba is semi-permeable and since the concentration of the

cytoplasm is higher than that in the environment surrounding amoeba, water molecules move by

osmosis from out into the cytoplasm of amoeba. The organism uses some of the water and excess

is secreted into the contractile vacuole, which is formed in the process. As the vacuole enlarges,

it moves towards the cell membrane and finally fuses with it. It then bursts to release the excess

water out.

Illustration

Insects.

Excretion in insects is carried out by structures called malpigian tubules, which are found

between the mid gut and the rectum of the insect’s alimentally canal.

Contractile vacuole fuses with cell

Vacuole expands due to entry of water.

Water enters vacuole from the surrounding

Vacuole releases water out of the cell A new

vacuole forms

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Insect tissues produce nitrogenous wastes in form of potassium urate, which is liberated into the

blood stream and taken to the malpigian tubules. In the tubules, urate reacts with Carbondioxide

and water to form uric acid, which is released out of the body along with feaces.

Diagram showing the position of the malpighian tubules.

CONTROL OF SALT LEVELS IN BLOOD

If the salt levels are high in blood, the blood concentration increases, this is detected by the

hypothalamus as blood flows through it. It then instructs the pituitary gland which then instructs

the adrenal gland to stop the production of aldosterone thus little or no salts get reabsorbed back

into the blood with in the nephrons.

If the salt levels are low in blood, the pituitary gland instructs the adrenal gland to release

aldosterone hormone which increases salt re absorption during urine formation leading to dilute

urine.

HOMEOSTATIC CONTROL OF BLOOD SUGAR IN HUMANS

Blood sugar is called glucose. Its concentration is controlled by a section of the pancreas called

islets of Langerhans. This gland regulates responding organs mainly the liver and muscles

through its secretions.

Importance of blood sugar regulation

1. It prevents cells running short of glucose in case its level drops. Blood sugar (glucose) is the

main source of energy.

2. Any slight increase in glucose level alters the concentration of blood’s osmotic pressure,

which results in alteration of the rate at which water moves in and out of the body cells by

osmosis.

Blood glucose concentration is controlled by the pancreas. The pancreas has glucose receptor

cells which monitor the concentration of glucose in the blood, and it also has endocrine cells

(called the islets of Langerhans), which secrete two hormones. The alpha cells (α cells) secrete a

Rectum

Malpighian tubule

Midgut

Anus

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hormone called glucagon, while the beta cells (β cells) secrete a hormone called insulin. These

two hormones are antagonistic, and have opposite effects on blood glucose.

Mechanism of blood sugar regulation

After a meal of carbohydrates, glucose is absorbed from the gut into the hepatic portal vein,

increasing the blood glucose concentration. This is detected by the pancreas, which then secretes

insulin from its beta cells.

Insulin causes glucose;

To be taken up by the liver and converted to glycogen and stored there.

To be converted into fats. Fats are stored in adipose tissue.

To be broken down to release energy at higher rate. This energy is stored in a form of

high energy compound called ATP. This reduces blood glucose in excess.

Once the concentration of blood glucose is lowered to a normal level, the pancreas stops

secreting insulin.

If the glucose level falls too far for example during starvation or fasting, the pancreas detects this

and releases glucagon from its alpha cells.

Glucagon causes;

Liver cells to convert stored glycogen into glucose.

Fats in adipose tissue to be converted to glucose.

The rate of oxidation of glucose to slow down.

This raises the blood glucose concentration to approximately normal level. Once this happens,

the pancreas stops producing glucagon.

Failure to produce insulin causes the presence of much glucose in urine a condition known as

DIABETS MELLITUS.

THE LIVER

The liver is the largest organ in the body of a mammal. It performs several functions, which

include the following.

1. Regulation of blood sugar level.

This is done with the help of a hormone called insulin from the β- cells of the islets of

langerhans, in the pancreas. When the blood sugar level is high, the pancreas produces

insulin, which moves to the liver cells through blood. It then stimulates the liver cells to

convert some of the glucose into glycogen for storage in the body. When the level of glucose

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drops in blood, it inhibits the secretion of insulin and stimulates the α- cell of the islets of

langerhans in the pancreas to secrete a hormone called glucagon. Glucagon stimulates the

liver to convert glycogen and fats to glucose. This raises the level of glucose in the blood.

2. Regulation of lipids.

The liver removes lipids from the blood stream by either breaking them down to release

energy or storing them in fat deposits.

3. Regulation of amino acids and proteins

The body cannot store excess proteins and amino acids therefore excess is sent to the liver

where the amino group (NH2) is removed from them and converted into ammonia or urea to

be excreted. This occurs in a process called deamination. The remaining part is broken down

to release energy or it is converted into fats for storage.

4. Detoxification.

This is the removal of toxic products from the body. All toxic products from any part of the

body are taken to the liver where their toxicity is neutralized.

5. Production of heat

When the body temperature falls, metabolic processes take place in the liver to produce heat,

which restores the temperature back to normal.

6. Production of bile.

Bile is manufactured in the liver and stored in the gall bladder.

7. Formation of cholesterol.

Cholesterol is a lipid part used in formation of cell membranes.

8. Elimination of sex hormones.

After their role is over, the sex hormones are modified and sent to the kidney or expelled into

bile by the liver.

9. Storage of blood.

The liver has a good network of blood capillaries and most of the blood is stored in these

capillaries. It holds more blood than any other body organ.

10. Storage of vitamins.

The liver stores most of the fat-soluble vitamins suck as vitamin E, vitamin D and vitamin K

11. Formation of red blood cells.

In adults the red blood cells are produced from the red bone marrows but in the foetus they

are made in the liver.

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12. Elimination of heamoglobin from red blood cells.

THE SKIN

This is the most extensively distributed tissue found all over the body of mammals. It is a

continuous protective layer over the body.

Functions of the skin

1. To protect the tissue below it from mechanical damage, bacterial and viral infections.

2. It also prevents excess loss of water from the body.

3. It acts as a sense organ and it is sensitive to pain, touch and heat. This helps the organism to

be aware of its environment.

4. It helps to keep the body temperature of endothermic organisms constant.

5. It synthesizes vitamin D in presence of sunlight.

6. It acts as an excretory organ. It excretes sweat, which contains urea, water and excess salts.

Structure of the skin

Hair Pore

Sweat duct

Sweat gland

Erector muscle of hair

Sebaceous gland

Venule

Arteriole

Sub-cutaneous fat

Hair follicle Nerve

Dermis

Epidermis

Cornified layer

Granular layer

Malphigian layer

Free nerve ending

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The skin consists of two main layers.

1. The epidermis (outer layer)

2. The dermis (inner layer)

The epidermis

This is made up of three sub layers.

a) The Malpighian layer.

b) The granular layer.

c) The cornified layer.

1. The Malpighian layer

This is the inner most sub layer in the epidermis. It consists of dividing cells which give rise to

cells of the granular layer. It secretes a pigment called melanin, which gives the skin its colour

and protects the skin from ultraviolent rays. Albinos do not produce melanin in their skins.

2. The granular layer

This contains living cells arising from the malphigian layer. It is the biggest layer of the

epidermis. It gives rise to cells of the cornified layer.

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3. The cornified layer.

This is the outermost layer of the skin. It is made up of dead cells, which are keratinized. Cells of

this layer continuously ware away and are replaced by cells from the granular layer. Its function

is to protect the inner parts of the body from mechanical injury and entry of bacteria and other

germs. It also offers water proofing to the skin.

The dermis

This is the inner layer of the skin. It is below the malpighian layer. It is thicker than the

epidermis. It contains the sweat glands, nerve fibers, fat cells and blood capillaries.

Other parts of the skin

1. Hairs.

The hairs extend from the dermis through the epidermis. They arise from hair follicles in the

dermis. They protect the body and trap a layer of air on the skin, which insulates the body against

heat loss.

2. Sebaceous gland

This secretes an oily substance called sebum. This oil softens the cornified layer and prevents it

from cracking. The oil also provides water proofing to the skin.

3. Nerve endings.

These perceive external stimuli and transport impulses to the central nervous system.

4. Sweat glands.

These are coiled tubular glands located in the dermis. They excrete sweat, which is released out

of the skin through the sweat duct.

CONTROL OF BODY TEMPERATURE (Temperature regulation).

This is the process of maintaining the temperature of the organism within narrow ranges, which

favour body activity, and ensures optimum activity of body enzymes.

To maintain the body temperature constant, there must be a balance between heat loss and heat

gain.

The body loses heat by;

a) Radiation: Heat diffuses from the warm body to the cold environment.

b) Conduction: The body loses heat to the cold object in contact with it.

c) Convection: Where cold air or wind carries heat from the warm body.

d) Evaporation: e.g. sweating leading to loss of heat

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The body gains heat by;

a) Radiation: e.g. from the sun’s heat and reflection from the ground.

b) Conduction: e.g. from the ground via the feet.

c) Convection: e.g. from the wind bringing hot air to the body.

d) Metabolism: e.g. since many of the body’s chemical reactions release heat e.g. in

respiration.

The rate of heat loss and gain depends on;

a) Surface area to volume ratio i.e.

Small organisms having a large surface area to volume ration tend to lose more heat than the

large ones with small surface area to volume ratio.

b) Temperature of surrounding environment:

Organisms tend to lose more heat in cold environment and gain more in hot environment.

c) Rate of respiration

The higher the rate of respiration, the more heat energy gained by the body.

d) Humidity of the environment

Heat loss increases in humid conditions because high humidity makes the environment

colder.

Endothermic/Homoithermic animals:

Endothermic organisms are those that are able to maintain a constant body temperature

irrespective of the surrounding environmental temperature.

They depend mainly on heat generated within their bodies. They are also called warm blooded

animals e.g. mammals.

Ectothermic/poiklothermic animals:

These are animals that cannot maintain a constant body temperature but their temperature

changes with that of the environment. They are also called cold blooded animals e.g. reptiles and

amphibians.

A graph showing how body temperature varies with environmental temperature

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endotherm

ectotherm

Environmental temperature

The body temperature of endotherms remains constant despite the increase in surrounding

temperature.

The body temperature of ectotherms varies with environmental temperature.

Control of body temperature in endotherms

When temperature is high, organisms respond in a way that lowers down the temperature and

when the temperature is low, organisms respond in a way that raises their body temperature.

These responses are categorized into two types.

1. Physiological responses. These are involuntary actions and they occur in body organs in

response to temperature changes.

2. Behavioral responses. These are voluntary responses from the organism. The organism

consciously decides what to do when external and internal temperatures change.

Response to cold weather in endothermic animals

Physiological means.

1. The erector pill muscles of the hair contract to make the hairs stand upright to the skin. The

hairs trap a layer of air, which insulates the skin.

2. The rate of sweating reduces in order to reduce on the amount of heat lost through it.

3. The metabolic activity of the liver increases to produce energy in form of heat.

4. Blood vessels near the skin constrict in the process called vasoconstriction to reduce on the

blood reaching the skin. This reduces heat loss through radiation.

5. Small animals like the mouse undergo hibernation where they dig holes and live deep in

them to reduce heat loss

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6. Shivering. This is the rhythmic contractions of the skeletal muscles. It results into production

of heat energy.

Behavioral means.

Endotherms may raise their body temperature behaviorally through;

1. Sitting near hot bodied to raise their body temperature by conduction or radiation.

2. Humans take hot drinks.

3. They do physical exercises to raise the metabolic activity of the body.

4. They can take a hot bath

5. They put on thick clothes, which insulate their bodies.

In hot weather

In hot environment, animals control the body temperature by increasing heat loss and lowering

heat production through the following ways:

Physiological means.

1. The erecter pilli muscle of the skin relaxes making the hairs to fall on the skin. This allows

heat loss by radiation.

2. The metabolic rate of the body reduces to reduce on the amount of heat produced.

3. Sweating increases. In this process excessive heat is lost as latent heat of vaporization to

evaporate the sweat from the body hence losing heat.

4. Vasodilatation. Vessels dilate and allow more blood to reach the skin surface in order to lose

heat to the surroundings by radiation.

5. Animals living in hot environments have a thin fat layer to reduce on the insulation.

Behavioral means.

1. Some rest on cold bodies like rocks to lose heat by conduction.

2. Humans sit near fans.

3. Some take cold drinks.

4. They put on light clothes

5. Panting. This involves hanging out of the tongue for example in dogs. This results into

evaporation from the mouth, which eventually cools the animal.

6. Swimming.

Adaptations of mammals to cold conditions

1. They have a lot of hairs over their bodies to trap a layer of air

2. They have a thick fat layer to act as an insulator.

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3. Some are very big and thus have a small surface area to volume ratio. This reduces the rate of

heat loss.

4. They have few sweat glands to reduce of the heat lost during sweating

5. They have fewer blood vessels on the skin surface to avoid heat loss through radiation.

Behavioral

1. Putting on thick clothes like in humans

2. Doing physical exercises

3. Hibernation. This is a state of long rest by burrowing into crevices and holes during extreme

coldness.

4. Sun bathing

Adaptations to hot conditions

1. Having little hairs on the body to allow easy loss of heat.

2. Having less fat to reduce on the insulation effect of fats.

3. Having a large surface area to volume ratio. To allow a faster rate of heat loss.

4. Having a lot of sweat glands to increase heat loss.

5. Having many blood vessels near the skin for easy loss of heat by radiation.

Behavioral.

1. Resting under shade.

2. Bathing cold water.

3. Aestivation. This is a state of long rest by burrowing in crevices and holes during extreme

hotness.

4. Putting on lighter clothes.

5. Sitting near cold things.

TEMPERATURE CONTROL IN ECTOTHERMIC ANIMALS

Ectothermic animals are animals whose body temperature changes with that of the environment.

Examples of ectotherms are, fish, reptiles and amphibians. Their body temperature is controlled

by only behavioral means.

During hot conditions, they lose heat by.

1. They rest on cold rocks to lose heat by conduction.

2. They rest on cold stones and in shades to lose heat.

23

3. They burrow in cracks and lose heat by radiation.

4. Aestivation. This is a state of long rest by burrowing underground or under rocks during high

temperatures.

5. Thermal gaping. This is the opening of the mouth to lose water by evaporation. This results

into cooling. Thermal gaping occurs in crocodiles and a few other reptiles.

During cold conditions, they gain heat by;

1. Resting on hot rocks to gain heat by conduction.

2. They rest under the sun to gain heat by radiation.

3. They rest near hot bodies to gain heat by radiation.

4. They burrow in hot sand to gain heat by conduction.

5. Basking in the sun to gain heat.

6. Hibernation. This is a state of long rest by burrowing into crevices and holes during extreme

coldness.

Merits of being endothermic

1. They are always active because their temperature is maintained at an optimum temperature

for enzyme activity.

2. They can live in a wide range of environments i.e. both hot and cold.

3. Their metabolic rate is maintained at a high rate due to the ability to maintain a constant body

temperature.

Disadvantages of being endothermic

1. Having a high rate of food consumption due to high rate of metabolism.

2. Maintaining the body temperature constant requires much energy.

Advantages of being ectothermic

1. Low food consumption due to low metabolic rate.

2. Easy to control body temperature by only behavioral means.

Disadvantages of being ectothermic

1. They have limited body activity in cold environments.

2. Slow response to stimuli due to low metabolic rate.

24

SAMPLE QUESTIONS

(a) (i) Give the main difference between cold-blooded (ectothermic) and warm blooded (endothermic) animals. (ii) Give one advantage that an endothermic animal has over an ectothermic animal. (iii) Why are ectothermic animals said to be cold-blooded? (b) Give four ways in which an ectothermic reacts to the lowering of external temperature. 2. (a) List the excretory products of animals. (b) With the aid of a labeled diagram describe the part played by the mammalian kidney in excretion. 3. (a) Which is the excretory organ for nitrogenous wastes? (i) In insects (ii) In an amoeba (b) Where is the organ located in the body of an insect? (c) (i) What nitrogenous compound is excreted by the organ in (b) above? (ii) Give a reason for the form of the excretory product you have mentioned in c(.i) above. (iii) Name any other excretory products in insects. What other function does the excretory organ in the amoeba perform? 4. (a) Describe how the human body controls temperature.

(b) What is the importance of having a constant body temperature?

5. (a) What is the importance of water to animals? (b) Describe how water balance in the mammalian body is maintained 6. (a) What is Osmoregulation? (b) How does the pituitary gland regulate the Osmotic pressure of the blood and tissue fluid?

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

S 3 CHEMISTRY HOLIDAY PACKAGE 

SULPHUR AND ITS COMPOUNDS 

SULPHUR AND ITS COMPOUNDS  Sulphur s a non‐ metal with atomic number 16, position 16, group VI and period 3 in the periodic table.  

 Occurrence; Occurs naturally as free Sulphur underground, as hydrogen sulphide in petroleum and in ores of metals as metal sulphides.  Extraction of Sulphur 

Is carried out by the Frasch process  A hole is dung in the underground to reach the Sulphur bed.  A Sulphur pump, consisting of three concentric tubes /pipes is sunk into the hole up to the Sulphur bed. 

In the outer most pipe, super‐ heated water under pressure is forced down to the Sulphur bed to melt the Sulphur. 

Hot compressed air under pressure is sent down the Sulphur bed through the innermost pipe.  This pushes the molten Sulphur and water up through the middle pipe.  Sulphur is then collected and water is evaporated off. 

 

Diagram of Sulphur pump showing how it is used to extract Sulphur. (research and draw)  Allotropes of Sulphur   Allotropes are different forms of the same element existing in the same physical state.  

Sulphur has up to 5 allotropes Crystalline allotropes   Non‐crystalline Rhombic Sulphur (alpha)   Amorphous Sulphur 

Monoclinic Sulphur (beta)   Plastic Sulphur 

  Colloidal Sulphur   The most important allotropes are Rhombic Sulphur and monoclinic Sulphur. Rhombic Sulphur is only stable below 96 . Above this temperature, it slowly changes to monoclinic Sulphur. Monoclinic Sulphur is only exists above 96 . 96  is called the transition temperature of Sulphur.  Structure of Rhombic Sulphur (research & draw)   

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

Structure of monoclinic Sulphur (research & draw)   LESSON 2 Differences between rhombic and monoclinic Sulphur  Rhombic Sulphur    Monoclinic Sulphur  

• Stable below 96     • Bright yellow  • Density is 2.08 g/cm3  • Crystals are octahedral in shape  

• Stable above 96     • Pale yellow  • Density is 1.98 g/cm3  • Crystals are needle shaped  

     Uses of Sulphur   

• Used in the vulcanization of rubber. • Used in the manufacture of drugs, ointments and fungicides used for treatment of skin diseases  • Used in the manufacture of sulphuric acid in the contact process.  • Used in the manufacture of gun powder, matches, and fireworks.  • Used in the manufacture of calcium hydrogen sulphide, a bleaching agent for wood pulp.  • Used for making paper.  

  Physical properties of Sulphur 

  • It is yellow non‐metal solid at room temperature. • It is insoluble in water • It is a poor conductor of heat and electricity • It is soluble in in carbon disulphide.  

Evidence to show that monoclinic and rhombic Sulphur are allotropes of Sulphur   When equal amounts / same mass of monoclinic and rhombic Sulphur are separately burnt in air they produce the same volume of Sulphur dioxide gas obtained in each case. 

        LESSON 3 Preparation of rhombic Sulphur  

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

Powdered Sulphur is shaken with carbon disulphide in a test tube for some time in absence of any flame around. 

The contents are filtered into a dry beaker through a dry filter paper placed in a funnel.  A filter paper is fastened over the mouth of the beaker and some pin holes are made through it.  The setup is placed near a window for some time to allow carbon disulphide to evaporate off slowly. Crystals of rhombic Sulphur are formed after evaporation of carbon disulphide. 

Preparation of monoclinic Sulphur   Place powdered Sulphur in a very large crucible .heat it and stir it gradually while adding some Sulphur until the crucible is full of molten Sulphur in absence of flame. 

Allow Sulphur to cool .After some time, a solid crust begins to form on the surface.  When the crust has formed make two holes at wide separation using a glass rod on it and pour out the molten Sulphur from inside which is not crystallized 

Remove the crust and observe needle shaped crystals of monoclinic Sulphur formed beneath the crust and throughout the inner surface of the crucible    

     Chemical properties of Sulphur    

1) Reaction with metals; Sulphur combines directly with heated metals e.g. iron, copper, magnesium, zinc to form metal sulphides.  

For example; if finely divided iron is mixed with Sulphur powder and the mixture heated, the two elements react vigorously; a red glow appears and a black/ dark grey solid of iron (II) sulphide is formed.  Equation 

      

   

 Research qn: 

State three ways that can be used to distinguish between the original mixture of iron powder and Sulphur powder and the substance formed after heating.   

2) Reaction with oxygen/air  Sulphur burns with a blue flame forming Sulphur dioxide gas (even in plentiful supply of oxygen) 

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

  3) Reaction with acids  

(a) With concentrated sulphuric acid, it oxidizes Sulphur to Sulphur dioxide and acid is 

reduced to water.   

(b) With concentrated nitric acid. When heated with Sulphur, reddish brown fumes of nitrogen dioxide gas are formed. Sulphur is oxidized to sulphuric acid.  

  4) Reaction with hydrogen; when hydrogen gas is bubbled thorough molten Sulphur in a boiling 

tube. Hydrogen sulphide gas is given off. 

    LESSON 4 

COMPOUNDS OF SULPHUR   

1. Hydrogen sulphide gas     Laboratory preparation; It is prepared by reacting dilute hydrochloric acid or sulphuric acid  with iron (II) sulphide.  

  Set up of apparatus (A new Certificate chemistry by Holderness pg 425) 

 

   

 

 Procedure: Dilute hydrochloric acid is added to iron (II) sulphide in a flat bottom flask. The hydrogen sulphide produced is collected over warm water because it is more soluble in cold water. equationn 

 Research: Describe how hydrogen sulphide can be prepared starting from Sulphur. Write an equation for the reaction of iron (II) sulphide and dilute sulphuric acid.  Physical properties of hydrogen sulphide gas   

• It is colorless  • It is denser than air  • It has a characteristic smell of rotten egg  • It is fairly soluble in water and its solution in water is acidic i.e. turns blue litmus red.  

 LESSON 5 Chemical properties of hydrogen sulphide gas  

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

  1) Reaction with oxygen (air). It burns in excess air to form sulphurdioxide and water.  

 In limited oxygen, yellow solid of Sulphur and water are formed.  

       2) Reaction concentrated sulphuric acid or concentrated nitric acid 

  3) Reaction with iron (III) chloride solution. Yellow colour of the solution changes to green due to 

formation f iron (II) chloride and yellow deposit of sulphur is formed.  

  Note: In reaction 2 and 3, hydrogen sulphide behaves as a reducing agent.   Testing for hydrogen sulphide gas in the laboratory     Reagent    Procedure   observation  

Lead acetate solution or lead (II) nitrate solution  

Filter paper soaked in lead acetate/lead (II) nitrate solution is dropped into a gas jar containing hydrogen sulphide gas  

The filter paper turns from white to black due to the formation of lead (II) sulphide.  

  LESSON 5 

2. Sulphur dioxide (sulphur (IV) oxide)   Laboratory preparation; two main methods are used: 

(i) From the reaction between copper metal and hot concentrated sulphuric acid 

lab. set up of apparatus (research and draw)   

  Procedure   

• Concentrated sulphuric is added to copper turnings in a round‐bottom flask and the mixture is heated.  • Sulphur dioxide gas is produced according to the following equation: 

 • It is passed through concentrated sulphuric acid to dry it;  and then collected by downward 

delivery because: - it is denser than air. -  it is very soluble in water (hence even if it was not required dry, it would not be collected over 

water)  

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

(ii) By reacting sodium sulphite with either concentrated sulphuric acid or concentrated hydrochloric acid  

  Procedure  

• Dilute sulphuric acid or hydrochloric acid is added to sodium sulphite  crystals in a flat‐bottom flask by means of a thistle funnel. It is then dried using concentrated sulphuric acid and collected by down ward delivery.   

Qn. Write an equation for the reaction of sodium sulphite and dilute sulphuric acid. LESSON 6 Physical properties of sulphur dioxide gas  

• It is a colourless gas.  • It has a chocking irritating smell.  • It is denser than air.  • It is soluble in water forming sulphurous acid.  

   Sulphurdioxide is therefore an acid anhydride (an oxide of a non‐metal that reacts with water to form 

an acid).    Test for sulphur dioxide in the laboratory    Reagents    Procedure    Observation   

Acidified potassium permanganate solution   

Bubble sulphur dioxide gas through a solution of acidified potassium permanganate.  

The purple colour of the solution changes to colourless.  

Acidified potassium dichromate solution  

Bubble sulphur dioxide gas through a solution of acidified potassium dichromate.  

The orange colour of the solution changes to green.  

  Chemical properties of sulphur dioxide gas    

1) It is an acidic oxide; it turns damp blue litmus paper red and forms sulphurous acid when dissolved in water.  Due to it acidic property, it reacts with sodium hydroxide (which is a base) to form  sodium sulphite (normal salt) if it is in limited supply i.e   

  or sodium hydrogen sulphite (acidic salt) if it is in plentiful supply. 

  

� 

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

 LESSON 7 

2) As a reducing agent; In its reaction with acidified potassium permanganate or acidified potassium dichromate, it behaves as a reducing agent.   

3) As an oxidizing agent.  - Sulphur dioxide oxidizes hydrogen sulphide to sulphur as it is reduced to water.  

 Therefore when the two gases are mixed, a yellow deposit of sulphur is observed. 

- It oxidizes magnesium to magnesium oxide. A yellow solid of sulphur and white solid of magnesium oxide are formed.  

                                      White           Yellow    

- When a piece of magnesium ribbon is added to a gas jar of Sulphur dioxide, the ribbon continue burning with a bright flame and a white ash and a yellow solid are formed; 

                     Mg(s)   + SO2(g)                 MgO(s)   +  S (magnesium displaces Sulphur from its oxide and continues burning in oxygen forming white magnesium oxide and brown Sulphur)  

-  Bleaching action. Sulphur dioxide gas acts as a bleaching agent ( a substance that removes colour) when dissolved in water. This is shown by dropping a moist blue/red flower into a gas jar of sulphur dioxide. The flower loses their colour (turn white). At first, sulphur dioxide reacts with water to form sulphurous acid;  

  Sulphurous acid takes up oxygen atom from the pigment of the flower and in the process, the blue flowers become white (bleached).  

                                     Blue                                                              White   

As a single equation: 

SO2(g) +  H2O(l) + [Dye +O]                H2SO4(aq)  +  Dye  OR 

SO2(g) +  2H2O(l) + Dye                         H2SO4(aq)  +  [Dye+2H] 

    

NB. Sulphurdioxide bleaches by reduction (removing  oxygen from the dye). 

 Uses of sulphur dioxide gas    

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

• Used in the contact process for the manufacture of sulphuric acid.  • Used to bleach wool, straw and sponges which are damaged by chlorine.  • Used as a bleaching agent in paper industry. • Used for fumigation due to its poisonous nature 

 

Exercise  

LESON 8 

Sulphuric acid This is a strong dibasic acid because it ionizes completely to produce many hydrogen ions.  

 Industrial manufacture of sulphuric acid  On a large scale, sulphuric acid is manufactured by the contact process from sulphur.  Procedure used: Sulphur is burnt in air to form sulphur dioxide in a sulphur burner  S(s) + O2(g)                               SO2(g) The sulphur dioxide formed is purified and dried in a cleaning and drying chamber. 

Sulphur dioxide is then mixed with excess air (oxygen) and the mixture passed over vanadium pentoxide (V2O5) /platinum catalyst heated to a moderate temperature of 400‐500  and under a pressure of 200 atmospheres. The two gases react to form sulphur trioxide gas. 

   The sulphur trioxide formed is dissolved in concentrated sulphuric to form a fuming liquid called oleum.  

 

The oleum is carefully diluted with water to form ordinary concentrated sulphuric acid. 

 Scheme of the production process showing the different stages involved (research) 

   

Think: Explain why sulphur trioxide is first dissolved in concentrated sulphuric acid instead of water Answer:  In water, sulphur trioxide dissolves violently to form sulphuric acid with evolution of a lot of heat. Acid sprays are formed which results into loss of the acid during production and damaging of manufacturing equipment. This problem is overcome by dissolving sulphur trioxide in concentrated sulphuric acid. 

  

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

Uses of sulphuric acid  • Used in the manufacture of fertilizers e.g. ammonium sulphate.  • Used in the manufacture of detergents e.g. omo, nomi  • Used in the manufacture of paint and pigments of dyes.  • Used in the manufacture of man‐made fibers for making clothes e.g. nylon.  • Used in car batteries or accumulators as electrolyte.  • Used in making explosives.  • Used as a drying agent.  • Used in extraction of some metals.  

  Lesson 9  

Properties of sulphuric acid These are divided into three categories; 1. As an acid 

(a) Sulphuric acid only behaves as an acid when dilute. This is because in the presence of water, it ionizes to form hydrogen ions. It turns blue litmus paper red  

  • When fully concentrated, it has no acid properties because there is not water for it to ionize and 

form hydrogen ions.  • When water is added to concentrated sulphuric acid, a lot of heat is produced which makes the 

reaction violent. (b) It reacts with metals above hydrogen in the reactivity series to form hydrogen gas and a salt.eg  

  (c) It reacts with carbonates and hydrogen carbonates to form carbon dioxide, water and a salt.e.g  

  (d) It reacts with bases forming salts and water only (neutralization reaction).eg  

  2. As a dehydrating agent  Concentrated sulphuric acid has a very high affinity for water hence it can remove it from air (drying agent) and other compounds. E.g   

(a) It removes water from hydrated copper (II) sulphate. The blue crystals turn white due to formation of anhydrous copper (II) sulphate. 

   Blue                                   White  

(b) It removes water from sucrose (C12H22O11) or glucose (C6H12O6); When concentrated sulphuric acid added to sugar crystals (sucrose) in a beaker, the sugar turns brown and finally turns to a black spongy mass of carbon. The black spongy solid swells and fills up the beaker. Steam and a lot of heat are also formed.  

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

Finally, a black solid that swells and fills up the beaker is formed. 

 

 

 

 

(c) Sulphuric acid also dehydrates ethanol (C2H5OH) to form ethene gas 

    

3. Oxidizing properties. It behaves as an oxidizing agent when concentrated.  Hot concentrated sulphuric acid oxidises 

(i)  copper to copper (II) sulphate. 

   (ii) carbon to carbon dioxide  

  (iii) Sulphur  

  (iv) Hydrogen sulphide to sulphur 

    Lesson 10 

Sulphates   

1) Solubility. All are soluble in water except lead (II) sulphate, calcium (II) sulphate (sparingly soluble) and barium (II) sulphate.  

2) Action of heat; Sulphates decompose on heating forming a metal oxide and sulphur trioxide gas except iron (II) sulphate and ammonium sulphate.  

e.g 

‐  Zinc sulphate decomposes to give yellow solid when hot and white when cold.  

   

When blue crystals of hydrated copper (II) sulphate is heated gently, it turns to a white powder (anhydrous copper (ii) sulphate). On further heating, the white powder (anhydrous copper (ii) sulphate) decomposes to a black solid (copper (II) oxide) and white fumes of sulphur trioxide. 

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

 Green crystals of hydrated iron (II) sulphate on gentle heating lose water of crystallization and turn white. 

  On further (strong) heating, the white powder decomposes to reddish brown solid of iron (III) oxide, white fumes of sulphurtrioxide and sulphur dioxide gas.  

  

   

Testing for Sulphates and Sulphites - Both sulphate ions and sulphite ions form white precipitates with; (i) Barium nitrate/barium chloride solution followed with dilute nitric acid/hydrochloric acid. 

  However, barium sulphite dissolves in the acid with bubbles of a colourless gas to form a colourless solution 

(ii) Lead (II) nitrate solution  Equations  

Pb2+(aq)  +   SO42‐(aq)                              PbSO4(s) 

Pb2+(aq)  +   SO32‐(aq)                              PbSO3(s) 

 Therefore, Barium nitrate/barium chloride solution followed with dilute nitric acid/hydrochloric acid can be used to confirm the presence of sulphate ions.  

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

O’ level Chemistry Sulphur and its compounds

1. (a) State what would be observed when the following are reacted. (i) Potassium nitrate and concentrated sulphuric acid. (1/2 mark)

....................................................................................................................................................................

(ii) Lead (II) nitrate and dilute sulphuric acid. (1/2 mark) ....................................................................................................................................................................

(b) State the condition for the reaction in (a)(i). (1/2 mark) ....................................................................................................................................................................

(c) Write equation for the reaction in (i) (a) (i) (1 ½ marks)

....................................................................................................................................................................

(ii) (a) (ii) (1 ½ marks) ....................................................................................................................................................................

....................................................................................................................................................................

P1/section A/ 2012 2. (a) State what would be observed when a mixture of iron filings and sulphur is warmed with

(i) carbon disulphide. (01 mark) (ii) dilute sulphuric acid. (02 marks)

(b) A mixture of iron filings and sulphur was heated strongly. (i) Name the substance that was formed. (½ mark) (ii) Write equation for the reaction between the substance you have named in (b) (i) and dilute hydrochloric acid. (1½ marks)

P1/section A/ 20103. (a) Sodium chloride reacts with sulphuric acid to produce hydrogen chloride gas according to the followining equation:

NaCl(s) + H2SO4(aq) NaHSO4(aq) + HCl (g) (i) State the conditions for the reaction. (1½ marks) (ii) Calculate the volume of hydrogen chloride gas that would be produced at room

temperature if 5.85 of sodium chloride was completely reacted with sulphuric acid. (02 marks)

(b) Dry hydrogen chloride was passed over heated iron. (i) State what was observed. (½ mark) (ii) Write equation for the reaction that took place. (1½ marks)

P1/section A/ 20104. (a) (i) State the conditions under which sulphuric acid can react with sodium nitrate to form nitric acid. (ii) Write equation for the reaction in (a) (i) above. (b) Sulphur was warmed with concentrated nitric acid. (i) State what was observed. (ii) Write equation for the reaction.

P1/section A/2007

 

  Prepared by Mr Victor ‐ Chemistry department Trinity senior Academy 

 

 

S3 AGRIC NOTES 

 

ANIMAL NUTRITION  

A process by which living things receive food necessary for them to grow and be healthy.  

A nutrient is a substance that is needed to keep a living thing alive and help it Grow  

Terms used in animal nutrition.  

Ration. This is the amount of food needed by an animal in a day.  

Balanced ration This is a ration that contains nutrients needed for both maintenance and production  

Maintenance ration This is the amount of food required by an animal to keep it healthy and alive in good health without gain or loss of weight.  

Production ration This is the food required by an animal over and above maintenance ration for additional output / performance e.g. milk production, egg production, fattening, growth etc.  

Digestibility This is the measure of that proportion of food eaten by an animal less that lost through feaces or the proportion of food absorbed in the body less that lost in feaces.  

Digestible crude protein This is the measure of N2 in the feed consumed and retained in the body of the animal after subtracting that lost through feaces, urine and gasses.  

Starch equivalent This is the amount of pure starch which has the same energy as a 100 kg of a particular feed  

Total digestible nutrient This is the sum total of all digestible nutrients in a feed.  

Crude protein The rough measure of the amounts of protein in a feed expressed as a percentage of dry matter or this is the product obtained between total nitrogen in a feed and a factor of 6.25 i.e. total nitrogen x 6.25  

Roughage. These are feeds that have high fibre content, low energy and protein usually constituting the main diet for ruminants e.g. green fodder, hay, e.t.c.  

Concentrates These are feeds with a high protein and carbohydrates, low fibre, and are highly digestible e.g. ground nut cake, fish meal, molasses, cotton seed cake etc.  

Protein supplements. These are feeds with a high protein content of over 30% e.g. fish meal cotton seed cake, Soya beans, etc.  

Basal feed. These are feed with a high content of carbohydrates that can provide energy e.g. maize bran, rice bran, mainly cereals and wheat bran.  

Bulk feeds. These are feeds that contain a limited amount of nutrients in a given weight and usually have a high fibre content e.g. forages / roughages.  

Minerals These are food stuffs found in small amounts in all feed stuffs consumed by the animals and are able to supply irons like calcium, phosphorous, sodium etc.  

Examples of animal mineral sources are oyster shells, bone meal, and mineral lick.  

Biological efficiency; it is the measure of the amount of out put per feed eaten by an animal. In lactating animals it can be amount of milk give per kg dairy meal consumed  

Economic efficiency; it is the measure of the cost of animal products to that of inputs like feeds e.g.  

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Output X price  

Feeds taken X price  

Gross energy efficiency; energy output of an animal per energy intake i.e.  

Energy output in products  

Energy taken in feeds  

Net energy efficiency; the measure of real energy output in products fro feeds eaten i.e.  

Energy out put in product  

Energy taken in – maintenance energy cost  

Determining feed digestibility  

In practice, digestibility is determined for dry matter, proteins, fats and crude fibre. Digestibility is just a proportional of food absorbed in the body less feacal nutrient. Therefore  

Digestibility = Nutrient intake (NI) ‐ Nutrient in feaces (NF) x 100%  

Nutrient Intake (NI)  

= NI – NF x 100%  

NI  

Example  

A fattening animal was given a feed containing 500g of proteins and later 150g of the same protein was found in the feaces.  

Calculate the digestibility of such a feed.  

Digestibility = NI – NF x 100  

NI  

= 500 – 150 x 100  

500  

= 350 70  

5 1  

= 70%  

Methods of determining feed digestibility  

Conventional total collection  

This involves giving an animal a constant daily feed intake and recording amount taken and feacal output.  

Indicator method  

In this method an inert substance is mixed with feeds and used as an indicator in determining the digestibility of a particular feed.  

Characteristics of a good indicator  

• It should be harmless to the animal  

• It should not be digested by the animal  

• It should be harmless to rumen microbes  

• It should readily mix with feeds.  

• It should be able to pass through the alimentary canal uniformly.  

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The indicators are of two types i.e. external indicators which are not part of the feed e.g. chromic oxide ad internal indicators which are part of the feed e.g. chromogens, ash etc.  

FACTORS AFFECTING FEED DIGESTIBILITY  

Difference between species  

Ruminants are more efficient in utilizing feeds than non ruminants due to their long digestive system hence will digest most of the feed taken.  

Age of the animal  

Very old and young animals have insufficient digestive systems hence show low digestibility of feeds.  

Individual differences  

Animals of the same species have shown differences in their digestibility of the same kind of feed as much as 25%.  

Exercise  

A light exercise improves digestibility of a feed while heavy exercises depress it.  

Addition of molasses to animal feeds  

These will improve digestibility of feeds since they contain highly digestible carbohydrates.  

Type of feed  

Proteins and carbohydrates are more digestible as compared to other types of feeds.  

Associated effect of other feeds  

Increased intake of proteins will improve digestibility of fibre.  

Time  

The whole process of digestion needs time for it to be complete hence its important to allow enough time for digestion to take place.  

Presence of anti metabolites  

Some feeds may contain anti metabolites e.g. trypsin inhibitor in raw Soya beans.  

Health of the animal  

Sick animals will have a low digestibility of feeds due to the abnormal physiology.  

IMPROVING DIGESTIBILITY OF FEEDS  

1. Selecting animals with high digestibility naturally.  

2. Providing feeds with high nutrients value to animals.  

3. Avoid excessive exposure of feeds to rain and sunshine in order to maintain their quality.  

4. Avoid prolonged exposure of animals to harsh weather conditions by providing a shade.  

5. Provide ample salt and plenty of fresh water for the animals.  

6. Add molasses to feeds to improve digestibility.  

7. chop pasture and crush feeds to increase surface area for enzymatic action  

 

RATION FORMULATION  

In making any ration, the following considerations should be made:‐  

The cost of the feed  

Expensive feed stuff should always be limited in this ration since they may be uneconomical.  

Availability of feeds  

The feeds that make up the ration should be readily available in the environment to reduce transport costs.  

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If the animals under consideration need a lot of proteins the ration should answer their nutrient requirements.  

The palatability of the feeds used  

Feeds that are used in ration formulation must be highly palatable for animals to gain from it.  

The skills of a farmer  

The person formulating the ration should be highly skilled to produce what is required by the animal.  

The nature of the final product  

The ration made should be in a state that can be utilized by the animal.  

The age of the animals  

Animals at different ages require rations in different forms in a particular nutrient.  

FORMULATIONS:  

Proteins are the main criterion in determining the proportions of the ration components since they are more expensive and can’t be replaced as carbohydrates.  

The main method used in the person’s square.  

Examples  

1. A dairy farmer wants to formulate a ration containing 16% of crude protein. Using maize bran which is 8% crude protein and fish meal which is 40% crude protein into 5 bags each weighing 100kgs. Show the quantity of maize bran and fish meal used.  

Maize bran 8% C.P  

Amount of maize bran needed in 500 kg (5 bags of 100kg@)  

Maize bran 24 x 500kgs = 375kgs  

32  

Amount of fish meal needed in 500kg  

Fish meal 08 x 500kgs = 125kgs  

32  

2. A poultry farmer wants to make a ration of 18% crude protein using maize bran which is 15% crude protein, rice bran which is 20% crude protein, cotton seed cake 30% crude protein and ground nut cake 38% to make 500kgs of Feed. Maize bran and rice bran are mixed in a ratio of 2:1 and ground nut cake mixed with cotton seed cake in a ratio of 2:1  

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Maize bran 15% C.P x 2 = 30  

Rice bran 20% C.P x 1 = 20  

TOTAL 3 50  

50 = 16.6%  

3  

2. Protein supplements  

Ground nut. Seed cake 30% 2 60  

Cotton seed cake 38% 1 38  

TOTAL 3 98  

98 = 32.6%  

3  

Basal feeds needed = 14.6 x 500 kg = 456.25kgs  

16  

Protein supplement = 1.4 x 500 kg = 43.75kgs  

16  

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2/3 X456.25= 304.2 Kg  

Amount of rice bran needed  

456.25 – 304.2= 152.05  

Amount of G.nut cake needed  

2/3 X 43.75= 29.2 Kg  

Amount of Cotton seed cake needed  

43.75 ‐ 29.2 = 14.55 Kg  

3. Using the following data.  

Maize bran 15% C.P  

Elephant grass 12% C.P  

Soya bean meal 38% C.P  

Fish meal 40% C.P  

Formulate a ration which is 16% c.p with an allowance of 2% minerals.  

N.B Minerals do not contain any protein hence cannot contribute to 16% C.P of the feed being formulated  

100 – 2 = 98  

Therefore 16 x 100  

98 = 16.3% c.p of the final ration  

Basal feeds  

Maize bran 15% c.p 1 15 39  

Elephant grass 12% c.p 2 24 3 = 13%  

3 39  

Protein Supplement  

Soya bean meal 38% c.p 2 76  

Fish meal 40% c.p 1 40  

3 116  

116 = 38.6%  

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Total = 25.6  

Basal feeds needed = 22.3 x 98 = 85.40%  

25.6  

Protein supplement = 3.3 x 98 = 12.6%  

25.6  

Minerals 02%  

Given the following  

Wheat bran 22%C.P, cotton seed cake 35% C.P, Soya meal 38%C.P, fish meal 40% C.P  

Make a ration of 18% C.P. giving an allowance of 3% minerals. Mix fish meal, Soya meal and cotton seed cake in a ratio of 3:2:1  

100 – 3 = 97  

18 x 100 = 18.5%  

97  

Basal feeds  

Wheat bran 22%  

Protein supplement  

Cotton seed cake 35% 1 35  

Soya meal 38% 2 76  

Fish meal 40% 3 120  

6 231  

231 = 38.5%  

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Basal feeds needed 20 x 97 = 82.55 %  

23.5  

Protein supplements 3.5 x 97 = 14.44 %  

23.5  

Mineral 03%  

MAJOR CLASSES OF FEEDS  

There are 8 major classes of animal feeds according to Harris and Crampton. These include:‐  

Roughages and dry forage e.g. hay.  

Pastures – These include range plants, grasses or legumes fed green.  

Silage – This is fermented fresh grass.  

Basal feeds or energy feeds – maize bran, rice bran, maze grains etc.  

Protein supplement e.g. fish meal, blood meal, cotton seed cake, g/nut cake, sunflower, Soya bean meal etc.  

Minerals – These are a good source of minerals like ca, phosphorous, cobalt, mg, zn, etc copper etc.  

Vitamins e.g. A, B, C and B‐complex  

Additives: These are added to feeds to meet various requirement e.g. hormones that stimulate growth, antibodies to control disease, drugs to control disease, antibiotics to kill pathogens, heat synchronizing hormones, anti‐oxidants to control oxidation of oils in feeds and flavorings to improve feed flavour.  

1. MINERALS  

 

Importance of minerals in Animal production  

• They are responsible for tissue irritability e.g. calcium and magnesium.  

• Some are important for the physical and chemical reactions in the body e.g magnesium that activates enzymes.  

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• They are important in the clotting of blood e.g. calcium.  

• They play a structural role more especially in the skeleton e.g. calcium and phosphorous.  

• They maintain the osmotic pressure of blood and lymph fluid at the cell membrane e.g. potassium.  

• Some are important in the reproductive system e.g. Manganese which increases sex libido.  

• Some are important in the capture and harvesting of energy in the body e.g. phosphorous which is used in the combustion of Adenine diphosphate (ADP)  

 

N.B  

Some of the minerals do not function independently but in combination with others e.g. the anti rickets triangle which is made up of ca, p and vitamin D.  

Calcium  

Phosphorus  

Vitamin D  

Classification of minerals  

Minerals are classified into two major groups i.e. micro and macro elements.  

The macro minerals are; ca, k, p, Na, Cl, S, Mg, etc. The micro elements are Fe, Zn, Cu, I, Co, Mn, Mo, etc.  

Iron  

 

This is responsible for the synthesis of haemoglobin and the red blood cells.  

It’s also a co‐enzyme in the cytochrome system. Iron is stored in the liver and spleen of animals.  

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• It leads to anaemia, however anaemia may be hereditary and also lack of Cu, Co, and proteins can cause anaemia.  

• Parasitic attack can cause anaemia due to bleeding in the guts  

• Iron deficiency mainly occurs in young mammals because milk is a poor source of iron and also animals kept on concrete since they have no access to soil which a good source.  

 

Copper  

 

This is essential in the synthesis of haemoglobin and also as an enzyme activator. It occurs in pigments of hair and its deficiency leads to anaemia and depigementation of hair.  

Iodine  

 

This is a constituent of thyroxin responsible for regulation of metabolism in the body. Its deficiency leads to Goiter or enlargement of the thyroid gland.  

In pigs iodine deficiency causes giving birth to piglets without hair.  

N.B  

Cabbage and Soya beans contain substances which prevent the secretion of thyroxin.  

Manganese  

 

This is an activator of most enzymes and its deficiency leads to reduced reproductive processes like spermatogenesis, reduced sex libido, and star gazing in chicks i.e. (chicks die with their heads facing upwards)  

Calcium  

• Strengthens bones  

• Helps in blood clotting  

• Important in nerve transmission  

 

Deficiency  

• Weakened bones  

• Low milk production in lactating animals  

• Milk fever in lactating animals  

• Slow growth  

• Lameness  

Phosphorous  

• Strengthens bones  

• Improves growth  

• Improves fertility  

 

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• Poor growth  

• Reduced appetite  

• Poor milk yields  

• Low fertility  

 

Potassium  

 

Maintains concentration of body fluids  

Helps in nerve transmission  

Deficiency  

• Slow growth  

• General weakness  

• Nervous disorders  

 

Salt (Sodium chloride) Na+ and Cl‐  

 

Used in nerve transmission  

Deficiency  

• Reduced appetite  

• Loss of weight  

• Reduced milk yield  

• Death after prolonged deficiency  

 

2. WATER  

 

About 80 % of the animal’s body is water. Water performs a number of functions in the bodies of animals like;  

Being part of body fluids like blood, semen, and vaginal fluids  

Gives support to body tissues  

Regulates body temperatures through evaporation to reduce heat  

Acts as a solvent for many solutes in the bodies of animals  

Acts as media for many body reactions  

Can be used in hydrolysis reactions of the body  

It’s a medium of transportation of body nutrients  

 

Sources of water for the animal’s body  

Food eaten by the animal  

Water taken in directly  

Metabolic water resulting from chemical reactions  

Water stored in various forms in the animal’s tissue  

 

Factors that determine the level of water intake by livestock  

• Amount of feed eaten; animals eating a lot of feeds with less water will drink more water as compared to those eating less of such a feed.  

• Water quality; animals will take more of fresh water as compared to salty stinking water  

• Availability of water; animals drink more water once readily available at all times  

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• Increased environmental temperature; this increases water intake as animals lose more water by evaporation  

• Animal health; sick animals may take less water than expected  

• Level of animal production; high milk yielders take a lot of water to compensate for that lost through milk secretion  

• Type of animals; cattle will take more water than goats due to their size  

• Age of animals; young animals will take less water as compared to mature animals  

• Water temperatures; animals will take less of cold water as compared with warm water  

 

DIGESTION IN RUMINANTS  

1. Mouth  

Food is gathered here with the help of tongue and teeth, a process referred to as prehesion.  

There is also chewing of food (mastication) and mixing it with saliva (salivation). Chewing of the curd also takes place here.  

N.B. The saliva of ruminant animals does not contain any enzyme, but its work is to lubricate the bolus and facilitate passage through the oesophagus.  

2. Oesophagus  

This is a passage for the bolus from the mouth to the rumen  

Rough materials that escaped thorough grinding during preliminary mastication pass back to the mouth through oesophagus.  

It allows gases to escape from the rumen to the out in the process of belching.  

3. Rumen / pouch  

It has a surface with projections like a towel  

It acts as a store for food.  

It refines the food particles.  

It churns and mixes the food thoroughly with the rumen liquids.  

Coarse food particles are directed to the mouth for further chewing.  

Provides place for fermentation by microbes like bacteria, fungi and protozoa.  

Conditions that favour rumen microbes  

1. The pH ranging between 6.2 – 6.7 which is maintained by saliva and continuous removal of volatile fatty acids (ethanoic acid (acetic acid), propionic acid and butyric acid)  

2. Low levels of oxygen since most of the microbes can respire anaerobically.  

3. The temperature of about 390c in the rumen.  

4. Enough moisture from water drunk, animal feeds and saliva.  

5. Presence of macro minerals and some trace minerals in the rumen needed by microbes.  

6. Regular removal of digested material so that fresh materials are in contact with the microbes.  

7. Presence of readily fermentable carbohydrates like glucose, sugars and starch in feeds eaten.  

8. Adequate supply of energy and nitrogen which enhances microbial activities  

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1. They enable ruminants to utilize fibrous material by hydrolyzing cellulose into monosaccharide.  

2. They build up complete proteins from elementary nitrogen which can be used by the host animal.  

3. They can upgrade dietary protein to a standard needed by the host animal.  

4. They can synthesize vitamins K, B, C and B complex for the host animal.  

5. At death, they provide proteins to the host animal.  

 

4. Reticulum  

It’s known to have a honey comb structure surface. Regulates passage of food from the rumen to the Omasum and from the rumen to Oesophogus  

It allows fine food to enter the Omasum  

It stores heavy materials like stone, stick, wire swallowed with food that why its referred to as the hard wave stomach.  

5. Omasum  

It has a surface with flaps that resembles papers of a book.  

Most water and organic acids are absorbed here.  

Solid particles left in food are further ground by the muscular leaves of the Omasum.  

The leaves form a pumping action that causes food into the abomasum.  

6. Abomasums (true stomach)  

It has a smooth surface  

The walls secrete Hydrochloric acid and gastric juice .  

Gastric juice contains enzymes rennin and pepsin which digests proteins.  

Rennin curdles milk in young mammals.  

7. Small intestines.  

Digestion is completed here by the pancreatic enzymes like lipase, amylase, trypsin, maltase and sucrase.  

8. Large intestines  

It is where the absorption of water takes place.  

Factors affecting feed intake by the animal.  

1. Environmental temperature; high environmental temperatures reduce feed intake while low environmental temperature stimulate feed intake.  

2. Palatability of the feed; feeds that are highly palatable would be consumed in large quantities by the animals as compared with unpalatable feeds.  

3. Blood components; a high quantity of glucose and volatile fatty acids in the blood of ruminants will suppress feed intake.  

4. High lignin content in feeds will suppress feed intake since it has a low digestibility.  

5. Shift in hormonal balance; during pregnancy, feotal displacements of the rumen and reticulum and changes in hormones will affect food intake.  

6. The volume of the alimentary canal; when the alimentary canal is filled with feeds fast it will cause distention in the reticulo‐ rumen restricting further feed intake. Maditrwoth Cosmas EMAIL. maditcosmas@gmail.com  

 

7. Level of animal production; animals that produce a lot of milk will eat more feeds to compensate the loss in milk.  

8. Animal health; sick animals will take less feeds as compared with the health ones  

9. Amount of feed provided; animals will always strive to eat all what is provided hence giving a lot of feeds increases intake  

Carbohydrate digestion in ruminants  

Ruminants do not have salivary amylase therefore the first enzymes to act on carbohydrates are in the rumen  

Enzymes in the rumen for carbohydrates are produced by the microbes  

Microbial amylase and cellulase breaks down starch and cellulose respectively  

The end products for carbohydrate digestion in the rumen are volatile fatty acids (VFAs‐acetic/ ethanoic acid, propionic acid and butyric acid), methane and carbondioxide. Formic and lactic acids are produced in small amounts.  

The amount of acetic acid produced depends on the amount of fibre and starch in the diet. A diet with high fibre results in production of more acetic acid while consumption of high starch results into production of more propionic and butyric acids.  

VFAs are absorbed and utilized for energy production rather than glucose used in non ruminants  

Acetic acid is the main source of energy in ruminants.  

 

Nitrogen conservation mechanism in ruminants  

Digestion of coarse fodder in ruminants depends on the activity of micro organisms in the rumen.  

The micro organisms require supply of energy and nitrogen for their growth and multiplication. In return micro organisms brake down cellulose  

Nitrogen is very important in ruminant digestion since it can be used by rumen microbes and in the building up of ruminant protein. Therefore, it must be conserved  

 

It is conserved in the following ways;  

Ammonia absorbed from the rumen plus that arising from tissue metabolism is converted to urea.  

In non ruminants, urea would be lost in urine but in ruminants, it is recycled back to the rumen through salivary secretion and across the rumen wall.  

The recycled urea is utilized by the rumen microbes to build up proteins for the host animal.  

The proportion of urea to nitrogen recycled depends on the quantity of nitrogen in the diet  

Low dietary nitrogen causes more nitrogen from the liver being returned to the rumen to build protein  

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The cycle ensures continuous source of nitrogen for rumen digestion.  

 

NUTRITIONAL AND METABOLIC DISORDERS IN LIVESTOCK  

Nutrition deficiency disease may be caused by:‐  

i. Giving the animals too little feeds  

ii. Having a diet that is low in one or more nutrients.  

iii. Imbalance of nutrients provided to the animals.  

Grass Tetany  

 

This is also called grass stagers/ hypomaganesaemia. It affects cattle and sheep mainly and it’s caused by magnesium deficiency.  

Symptoms:  

• Animal becomes nervous  

• There is twitching of the muscles more especially those around the head and the neck.  

• The head of the animal is lifted high  

• There is accelerated respiration  

• There is increase in body temperature and gashing of the teeth.  

• Abundant salivation which is followed by death  

• It occurs during the 1st week of the pasture season.  

 

Control  

• Animals should be given mineral lick which contains magnesium sulphates, calcium and phosphorous.  

Bloat  

 

This is the distention of the rumen which may occur in all ruminants due to excessive gases produced by fermentation of feed stuffs.  

Causes:  

• Feeding of animals on young succulent grass with high protein content.  

• Rumen microbes interfering with normal release of gases  

• Some animals are more susceptible to bloat than others naturally.  

• Some plants contain compounds which tend to form lather (foam) once eaten by animals.  

• Feeding animals on feeds that are known to cause bloat.  

 

Symptoms:  

• Extension of the rumen  

• Difficulty in breathing  

• Loss of appetite / animal stops to eat  

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• Death of the animal  

• Animal lies down and sticks its legs out.  

 

Treatment:  

• Affected animal should be treated using a trocar and cannula which is used in piercing the rumen to release the gases.  

• The animal should be given mineral oil orally to open up the system so as to allow gases out.  

• Use of the broom sticks method where a small piece of stick is laid across the mouth of the animal to keep it open and allow gaseous out.  

 

Control / Prevention  

• Feed animals in good quality forage  

• Provide anti bloat drugs to animals  

 

Ketosis (acetonemia / pregnancy toxaemia)  

 

A disorder of animals caused by high production exceeding feeding capacity of the animal Occurs in high milk yielders during the first month of lactation  

Symptoms  

• Low blood glucose levels (hypoglycemia)  

• Rapid loss of body weight / emaciation  

• Nervousness may develop in the animal  

• Drop in milk yield for lactating animals  

• Apparent blindness  

• Walking in circles.  

 

Cause  

• Inadequate feeding for yields  

• Unsuitable feeds / inadequate roughage  

• Malfunctioning of the liver leading to increased keto acids in blood.  

 

Preventions  

• Adequate and proper feeding of lactating animals  

• Animals should have enough green pastures.  

• Animal should be exercised  

• For treatment, call a vet.  

 

ANIMAL HEALTH  

Health is a situation in which all body organs and systems are normal and functioning normally or it’s a state of well being where by all the vital processes of life related activities are functioning satisfactorily. Maditrwoth Cosmas EMAIL. maditcosmas@gmail.com  

 

Disease is any deviation from normal health or it’s a structural disorder and physiological abnormality which is harmful to the animal.  

Signs of good health in animals  

1. The skin of the animal is clean, smooth and shinny  

2. The animal is alert and easily responds to stimuli like touch.  

3. The animal has a normal appetite i.e. feeds greedily leaving no food in the trough.  

4. Body temperatures should be normal i.e. 38.60 in cattle, 39.10C in goats, 39.2 in pigs and 38.9 in sheep.  

5. The dung should be soft, neither excessively hard nor watery.  

6. The urine should be clear pale yellow with no blood stains or bad smell.  

7. The mucus membrane in the nose, mouth, eyes, and reproductive tract should be moist and pink in colour.  

8. Animal production, in terms of eggs, meat and milk should be normal and consistent with the stage of production.  

9. Lameness or abnormal movement is an indicator of disease.  

10. Continuous coughing and sneezing is an indication of disease.  

Causes of ill health in animals  

1. Heredity;  

Some diseases are transmitted through genes e.g. curved limbs in cattle.  

2. Microorganisms;  

These invade the body’s animals and cause various diseases e.g. T.B. East coast fever, New castle, etc  

3. Mechanical injuries  

These can be caused by sharp objects and sometimes rough handling of the animal like beating.  

4. Nutritional imbalances  

Lack of certain nutrients in the animal’s diet may cause disease e.g. lack of iron, causes anaemia.  

5. Poisoning  

Some pastures contain chemicals which can poison the animals e.g. hydrocyanic acid (HCN) found in cassava blocks respiration once taken in large amounts.  

6. Starvation  

Under fed animals in relation to their production are likely to suffer from a disease like Ketosis more especially lactating animals.  

7. Exposure to extreme conditions of the environment like high temperature or very low temperatures can cause stress.  

Factors that expose animals to disease (Predispose)  

• Age; Young animals have un developed immunity while the old ones have a worn out immune system which exposes both more to disease easily.  

• Climate; Very cold weather and humid conditions would expose the animals to respiratory infections like pneumonia.  

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• Pollution; Air and water pollution exposes the animals to many infections and may also cause poisoning.  

• Hereditary; Inheritance of large and pendulous udders in dairy animals predisposes such animals to disease like mastitis.  

• Breed; exotic breeds of cattle are more prone to tick borne diseases than indigenous cattle  

• Communal grazing; this brings herds of cattle together with those that are diseased hence predisposing the health animals  

• Mechanical injuries; these may act as entry points for the pathogens  

• Poor hygiene; this encourages pathogens to contaminate feeds and water hence easy spread of disease  

• Improper disposal of dead animals; animals that have died due to disease once disposed poorly may lead to easy disease outbreaks  

 

Classification of disease  

Infectious disease  

This is a disease caused by living organisms like bacteria, protozoa, fungi and virus.  

Non‐infectious disease  

This is a disease caused by something else other than living organisms’ e.g. blot, milk fever, goiter, grass Tetany, e.t.c.  

Contagious disease  

This is a disease transmitted by contact between infected animals and healthy ones e.g brucellosis.  

Communicable disease  

This is a disease that is transmitted from one animal to the other by both direct and indirect contact e.g. T.B, foot and mouth disease.  

Notifiable or reportable disease  

This is a very contagious disease, which spreads fast in herds or flocks and usually affects humans e.g. tuberculosis and anthrax.  

HOW DISEASES CAN BE SPREAD ON THE FARM  

• Introduction of sick animals to the farm, which can transmit disease to the healthy ones by contact.  

• Introduction of healthy animals that are carriers of certain diseases.  

• Diseases can also spread through contaminated water and feeds.  

• Vectors like tsetse flies and ticks can also transmit disease.  

• Wild birds and rodents may carry disease to the domestic animals through contaminating feeds and water.  

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• Contaminated equipment like vaccination equipment, drenching guns, insemination syringe may spread disease.  

• Shoes and clothing of any one who moves from flock to flock or in animal quarters can spread disease.  

• Airborne organisms like bacteria spores may be spread through air and cause disease.  

• Soil can Harbour resting stages for anthrax spores which can survive for up to 40 years.  

• Diseases can also be spread through infected animal products like eggs in birds can spread new castle to chicks  

• Improper disposal of dead animals that have died due to a certain disease  

• Dung or excreta incase of cows and other young stock can also spread disease.  

 

General Control of diseases on the farm  

• Farmers should make sure animal quarters are clean to keep off pathogens.  

• There should be adequate ventilation in the houses to control respiratory infections like pneumonia.  

• Ensure adequate spaces for each animal hence discourage over crowding.  

• Animals to be bought should be selected from reliable source with less risk of disease.  

• Institute quarantine measures incase of a disease outbreak in an area.  

• Practicing rotation grazing in cattle in order to control vectors like ticks.  

• The farmer should follow vaccination programmes for livestock in order to control disease.  

• Visitors to the farm should be restricted and those allowed in should be disinfected.  

• Sick animals should be isolated from the general herd or flock to reduce disease spread.  

• Dead animals should be properly disposed by either burning the carcass completely or burying it 3m deep in the soil.  

• Animals with highly infectious disease should be culled by slaughtering and burning the carcasses completely.  

• Newly bought in animals should be isolated from the general herd for At least 14 days to ensure that they are healthy.  

 

QN; Explain the Cause, symptoms, mode of transmission, animal attacked and control of the following diseases.  

a. Bacterial diseases  

Contagious abortion or brucellosis.  

Anthrax  

Mastitis  

Black quarter  

Foot rat  

Calf pneumonia  

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Fowl typhoid.  

 

b. Viral diseases  

Foot and Mouth Disease  

Rinder Pest  

New Castle  

Swine Fever (Hog Cholera)  

Fowl Pox  

Rabies.  

 

c. Protozoan diseases  

Nagana (Trypanosomiasis)  

Coccidiosis  

Anaplasmosis  

East coast fever  

Red water  

Heart water  

 

PARASITES  

This is an organism that derives benefit from another (host) while inflicting pain on it.  

TYPES OF PARASITES  

Obligate parasites  

These live their entire life as parasites and cannot survive without a host e.g. the tape worms.  

Facultative parasite  

These can live freely in the absence of a host and as a parasite in presence of the host i.e. fleas.  

Endo parasites  

They live in the bodies of the host and get their nourishment from there e.g. Liver  

Flukes, tapeworms, round worms, gape worms etc.  

Ecto parasites / External  

These live on the outer surface of the host and derive their nourishment from there e.g. ticks pig lice, mites.  

Ecto‐endo parasites  

These live in the outer skin surface of the host e.g. jiggers and menge in pigs.  

ECONOMIC IMPORTANCE OF PARASITES  

1. They increase cost of production since money must be spent in trying to control parasites.  

2. They make keeping of highly susceptible exotic stock very difficult e.g. ticks.  

3. Some parasites are vectors of important diseases like East coast fever, Nagana red water etc  

4. Some may suck a lot of blood from the animal leading to anaemia.  

5. They can cause retarded growth in the host after extracting a lot of nutrients.  

6. They reduce the quality of animal’s products like meat, hides and skins.  

7. They can cause loss of weight / emaciation/ loss of condition in the animals.  

8. Some can cause open wounds to the host which may give way to other pathogens.  

9. They can cause irritation to the animal leading to low production Maditrwoth Cosmas EMAIL. maditcosmas@gmail.com  

 

TICKS.  

Classification of ticks  

Kingdom Animalia  

Phylum : Arthropoda (jointed appendages)  

Class Arachinida (4 pairs of legs) the body is divided into 2.  

Order Acarina  

Super family Oxodoidae  

Sub families 1: Oxodidae (hard ticks)  

Sub families 2: Argasidae (soft ticks) mainly in chicken  

Hard ticks.  

These include the following;  

a. Bont tick – ( Amblyomma variegatum)  

b. Blue tick – ( Boophilus decoloratus )  

c. Brown ear tick ( Rhipicephalus appendiculatus )  

d. Red legged tick (Rhipecephalus evertsi)  

 

GENERAL LIFE CYCLE OF TICKS  

After matting, the female sucks blood to full engorgement.  

It later detaches off from the host and finds a suitable protected environment on the ground where it lays the eggs.  

Depending on temperature and humidity, the eggs would hatch into larvae at least after two weeks.  

The larva climbs on top of grass to try and find a host.  

After finding a host, the larva feeds for 3‐4 weeks then moults into a nymph.  

The nymph feeds for 4‐6 days before moulting into an adult.  

 

NB:  

The hard ticks are classified into three distinct types according to their life cycle i.e. one host tick, 2 host tick and 3 host tick.  

One host tick (blue tick)  

This type of tick utilizes one host for all the three instars i.e. larva, nymph and adult lifecycle.  

The larva feeds on a host until it moults into a nymph.  

The nymph feeds on the same host until it moults into an adult.  

The adults mate and take in blood up to full engorgement then drops off to the ground to lay eggs.  

After two weeks, the eggs hatch into larva and climb grass to wait for the host.  

Maditrwoth Cosmas EMAIL. maditcosmas@gmail.com  

 

 

This is the shortest life cycle covering up to three weeks. An example of such is the blue tick which transmits protozoa that causes Anaplasmosis  

 

(Gall sickness).  

Two Host tick (red legged )  

In this life cycle, the larva feeds on a different host while the nymph and adult feed on the same host or the larva and nymph feed on the same host while the adult on another.  

Larva climbs to the host, feeds on blood and after engorgement drops down to moult into a nymph.  

The nymph feeds on the same host until it moults into an adult while still there e.g. red legged tick that transmits Red water (Babesiosis).  

 

Three Host tick  

In this life cycle each istars feeds on a different host and all the immature instars i.e. larva and nymph moult on the ground.  

It’s the longest life cycle taking a minimum of three months.  

The larva climbs on the first host where they feed on blood up to full engorgement and later drop to the ground.  

While on the ground they moult into a nymph which climbs to another host.  

The nymph feeds on blood up to full engorgement and drops to the ground where it moults into an adult.  

The adult climbs another host and the cycle continues e.g. brown ear tick and bont tick  

Tick vector       Agent       Disease caused.  

1   Brown ear tick    

Anaplasma marginale  

   

 

2   Blue tick    

Anaplasma marginale  

   

 

3   Bont tick    

Rickettisia ruminatium  

4   Red legged tick   

 

 

S3 COMPUTER INTRODUCTION TO COMPUTERS.

(a) Mention the way (basis) of categorizing computer

• By size (physical, memory or numbers) • By process (digital, analogy or hybrid) or logic or functionality • Purpose (general or special) or function • By processor (PI-PIV, iseries)/process/type/power • How and where used (desktop, palmtop, laptops) • By Brand (Dell, Acer, Lenovo, Compaq, IBM) • By generation (1st -5th)

(a) Define the term Computer generations.

A computer generation refers to the development of computers today.

(b) List the generation and mention the distinguished characteristic there in.

First Generation (1940-1956) Vacuum Tubes

Second Generation (1956-1963) Transistors

Third Generation (1964-1971) Integrated Circuits

Fourth Generation (1971-Present) Microprocessors/Large scaleIntegration

Fifth Generation (Present and Beyond) Artificial Intelligence

(c) Differentiate between the first and fourth generation computers

First Generation computer Fourth generation computers

They used punched cards and paper tape for input.

Large scale integrated and very large- scale integrated circuits were developed and contained hundreds and millions of transistors on a tiny chip.

They used magnetic drums for memory.

Memory increased to hundreds of megabytes (100Mb)

They had memory size of approximately kilobytes of RAM

They had ram of up 2 Gb

Speed was about 10,000 instructions per second

Speed increased from 1 giga to tera instructions per second

consumed a lot of power Consumed less power

They produced a lot of noise. Very little or no noise

Very big in size Smaller in size.eg Phones

Mention four examples of computers in the first generation.

• ENIAC (Electronic Numerical Integrator and Calculator): It was the first electronic computer built by John Eckert and John Mauchy.

• EDVAC: It stands for Electronic Discrete Variable Automatic Computer

• EDSAC: It stands for Electronic Delay Storage Automatic Computer and was developed by M.V. Wilkes at Cambridge University in 1949.

• UNIVAC: (Universal Automatic Computer): Eckert and Mauchly produced it in 1951 by Universal Accounting Computer setup.

Mention four limitations of computers in the first generation

• The operating speed was quite slow.

• Power consumption was very high.

• It required large space for installation.

• The programming capability was quite low.

• Limited primary memory

• Generated a lot of heat

• Weighted about 30 tons

Mention four examples of computers in the second generation.

• CDC 3600:

• UNIVAC-III ,

• IBM-1600 Series,

• IBM-1400 Series.

COMPUTER SYSTEM

Define the term computer system in relation to computers.

A computer system is a set of components working together for a common goal. Failure of one of the system components may imply failure for the whole system.

The computer system basically consists of hardware, software, and human ware.

Other components are data and, communication.

Distinguish between data and information.

Data is raw facts and figures with no meaning While

Information is processed data with meaning.

Data can also be defined as a collection of unprocessed items.

HARDWARE

What is meant by the term computer Hardware?

Computer hardware components are tangible or physical (they can be touched).

(b). List any four categories of computer hardware.

Computer hardware includes

Input devices like the keyboard and mouse,

Processing devices like the Microprocessor Chip,

Storage devices like the Hard disks and the CDs,

Output devices like the monitor and the printer.

INPUT AND PROCESSING COMPONENTS

Explain the meaning of the term control unit as used in a computer system

The control unit is the component of the processor that directs and coordinates most of the operations in the computer.

State any two functions of the control unit.

The control unit directs and coordinates most of the operations in the

computer. It interprets each instruction issued by programs and then initiates the

appropriate action to carry out the instruction. the control unit performs the machine cycle which includes the steps

(Fetching, Decoding, Executing and Storing)

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a). Differentiate between input and input devices Input is data or instructions entered into the computer

While

An input device is any hardware component that allows you to enter data or instructions into the computer

ii). Define the following.

i. Text input devices

These are devices that help us to input text like letters, numerical digits, symbols and marks into a computer.

ii. Pointing input Devices

A pointing device is an input device, which allows users to move a pointer and make selections on the computer screen.

iii. Imaging input Devices

Imaging input Devices are devices that input images such as still photos, motion pictures, graphics, video etc. into the computer for processing.

iv. Gaming input Devices

Gaming input devices are devices specifically designed to be used for playing computer games.

v. Audio input Devices

Audio input device is a device used for entering any sound into the computer such as speech, music, and sound effects.

vi. Biometric input Devices

A biometric device translates a biological personal characteristic into a digital code that is stored or compared with a digital code stored in the computer.

(b). Give any four examples of each of the following input devices

i). Text input devices

The keyboard, Voice Recognition Equipment

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OMR and Barcode readers OCR and Optical readers MICR readers RFID readers Magnetic Strip Card Readers, etc.

ii). Pointing input Devices

Mouse Stylus pen & digitizing tablet Cordless Mouse Trackball Touchpad Light pen Touch Screen A Track Point

iii). Imaging input Devices

Image scanner Digital Camera Digital video (DV) camera Camcorder Web cam

iv.). Gaming input Devices

Gaming keyboard Gaming wheels Joysticks Game pad Light guns Dance pad Motion sensing game controllers

v). Audio input Devices

Microphones, Tape players, CD/DVD players, MIDI devices Dictaphone, E.t.c

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vi). Biometric input Devices

Fingerprint scanner Face Recognition systems Hand geometry systems Signature verification systems Iris Recognition systems

(c). Give three advantages of using a keyboard.

Keyboards are very common (commonly supplied with computers) Entering data and commands with keyboard is faster as compared to the

mouse Keyboards are more reliable

(d). Give three disadvantages of using a keyboard.

It takes a lot of time to practice in order to type quickly Keys can easily become faulty due to dust. Some keyboards keys are very hard to press, causing fingers to hurt.

ii). Mention any four keyboard layouts that you know

The QWERTY is referred to as the "Universal" keyboard. Dvorak, ABCDE, GKOS, QWERTZ and AZERTY

21. (a). Mention any three parts that make up a keyboard.

Typing keys (Alphabetical key pad): Which include letters of the

alphabet, numbers, punctuation marks, and other basic keys. Numeric key pad: on the right side of the keyboard. Functional Keys: which are labelled with the letter F followed by a number

(F.l, F2.........F12) Cursor movement keys

(b). State the practical importance of the following keys on your keyboard

(i). NUMLOCK key:

Used to convert to convert part of the keyboard with both numeric pad and separate arrow keys.

Page 13  of 

(ii). Esc key: It is used to cancel an application under taken

(c). Apart from the keyboard, state any three examples of text input hardware devices commonly used.

Voice Recognition Equipment OMR and Barcode readers OCR and Optical readers MICR readers RFID readers Magnetic Strip Card Readers, etc.

2. a). Explain the following mouse techniques.

(i). Clicking (single click)

This to point to the item on the screen, and then press and release the primary mouse button (usually the left button).

(ii). Double clicking

This is to point to the item on the screen, and then press and release the primary button mouse twice quickly (usually the left button).

(iii). Dragging

This is to point to the object on the screen, press and hold the primary left button, move the object to a new location, and then release the primary button.

(iv). Right clicking This to point to the item on the screen, and then press and release the secondary mouse button (usually the rightbutton).

(v). Scrolling

This is to roll the wheel backward (toward you). To scroll up, roll the wheel forward (away from you).

Give one function of each of the following keys (buttons) on the computer keyboard.

Enter Key (Execute key)

Page 14  of 

It is used to accept a command or execute a command. Or it is used to go to another line when typing

Back space key.

It is used to erase / rub characters to the left side of the cursor.

Space bar

It is the longest key on the keyboard and it is used to insert spaces between word and characters.

Caps lock.

It is used to turn capital letters into small letters and small letters into capital letters.

Shift key

It is used to activate characters on top of the buttons, it can also turn in either small letters or capital letters depending on the keyboard case mode.

Delete key.

It is used to erase characters on the right side of the cursor.

Fl: It is used as help.

Esc (escape): it is used to cancel an application under taken.

Distinguish between a CPU and system unit. The processor interprets and carries out the basic instructions that operate a computer.

While A system Unit is a case that houses (contains) the electronic components of a computer used to process data.

c). Name three major parts of the CPU.

Control Unit Arithmetic Logic Unit Registers

d). Explain the function of each part in (c) (i) above.

The control unit.

The control unit is the component of processor that directs and co- ordinates most of the operations in the computer.

Page 15  of 

Arithmetic Logic Unit The Arithmetic Unit is another component of the processor, which performs arithmetic, comparison, and Logic operations.

Arithmetic operations include basic calculations such as addition, subtraction, multiplication, and division.

Registers

The registers are devices that hold data inside the computer’s memory long enough to execute a particular function, such as indexing, calculating, sorting or otherwise manipulating data.

c). How does the use of the mouse make Windows easier compared to the use of the Key board alone?

i. The mouse provides quick access to common tools just by clicking. ii. You don’t have to practice a lot.

Name any four ports through which computer peripherals are connected.

o Serial o Parallel o USB o PS2 o RJ45 LAN port o PCMCIA port o ESATA port o IEEE1394 o Hot Swappable/plug and play o Micro ISD o Game port o Port A and Port B

Give and three components inside a computer which can be replaced or upgraded, when the computer is slow.

• RAM • Hard Disk • CPU • VGA Card/Video card

b). Outline any four uses of a computer system control panel.

• System and security management • Network and internet management • Hardware and sound management

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• Systems programs • User accounts and family safety • Appearance and personalization • Clock, language and regional settings • Ease of access • System configuration

ii). Explain a system interface

Systems or mechanisms or tools through which a user interacts with a computer system (which can be graphical tools, menus, command programs, voice and touch recognition tools. Remote control interfaces etc.)

Differentiate between an expansion slot and adaptor card.

An expansion slot is a socket on the motherboard that can hold an adapter card.

While

An adapter card, also called expansion card, is a circuit board that increases

the capabilities of the system or provides connections to peripherals.

ii). Outline any four examples of adaptor cards that can be connected to the motherboard.

Adapter Card Purpose

Sound card

Connects speakers or a microphone

MIDI card Connects musical instruments

Network interface card (NIC) Connects other computers

Video card Connects a monitor

USB card Connects USB devices

TV tuner card Allows viewing of television channels

Video capture card Connects a video camera

Modem card Converts telephone or cable analog signals t

FireWire card Connects FireWire devices

Page 17  of 

b). Define the term motherboard

The motherboard is a single main circuit board of the system unit, which provides the path through which the processor communicates with internal and peripheral devices.

ii). Outline four components of the motherboard

i. Processor chip (the CPU), ii. Memory chips, iii. Buses iv. Expansion Slots v. Adapter Cards.

iii).With examples device used by each differentiate between parallel and serial port.

A serial port is a type of interface that connects a device to the system unit

by transmitting data one bit at a time. It usually used to connect devices that do not required fast data transmission rates, such as a mouse or keyboard.

Parallel ports allow the parallel transmission of data; that is, several bits are transmitted simultaneously. These ports provide the interface for such devices as high-speed printers.

You are provided with the following computer hardware parts and other electrical accessories

i. AC main socket outlet ii. Uninterrupted Power Supply (UPS) iii. UPS power cable iv. System Unit v. System Unit power cable vi. Monitor vii. Monitor power cable. viii. Mouse. ix. Keyboard. x. VGA cable

Page 18  of 

Describe how they can be assembled to make a complete functioning computer.

• Connect the UPS to the AC mains socket outlet using the UPS power

cable. • Connect the monitor to the UPS using power the monitor power cable. • Connect the system unit to the UPS using the system unit power cable. • Connect the monitor to the system unit using VGA cable. • Connect the mouse to the system unit. • Connect the keyboard to the system unit.

NB: Accept a well labeled drawing of a computer system

Outline the logical order of switching on the computer system, assembled in (a).

(i) Turn on the AC main socket outlet. (ii) Turn on the UPS power supply switch. (iii) Turn on the monitor power switch. (iv).Turn on the system unit power switch.

OUTPUT AND STORAGE

1. Distinguish between primary and secondary memory

Secondary memory is computer memory used to store larger amounts of data, and information more permanently

While Primary memory is memory that provides a small amount of temporary storage area for the data and instructions required by the CPU for processing. Primary memory is memory found inside the computer

b). Give two types of RAM chips

Dynamic RAM (DRAM) must be refreshed (or recharged) constantly by the

CPU. Static RAM (SRAM) is faster and more reliable than any form of DRAM. The

term static refers to the fact that it does not have to be re-energized as often as DRAM.

Magneto resistive RAM (MRAM), stores data using magnetic charges instead of electrical charges.

MRAM has greater storage capacity, consumes less power, and has faster access times.

Virtual RAM (VRAM): Modern operating systems can use spare storage space on the hard disk as if it is working memory and this is referred to as Virtual memory or Virtual RAM

Page 19  of 

c). Outline two types of ROM chips PROM (Programmable Read only Memory)

PROM is read-only memory that can be modified only once by a user. The user buys a blank PROM and enters the desired contents using a PROM programmer.

EPROM (Erasable and Programmable Read Only Memory)

The EPROM can be erased by exposing it to ultra-violet light for a duration of up to 40 minutes. Usually, an EPROM eraser achieves this function.

EEPROM (Electrically Erasable and Programmable Read Only Memory) The EEPROM is programmed and erased electrically. It can be erased and reprogrammed about ten thousand times.

(d). Describe the features of ROM and RAM? RAM. These are semiconductor memories. It is known as main memory. Usually volatile memory. Data is lost in case power is switched off. It is working memory of the computer. Faster than secondary memories. A computer cannot run without primary memory.

ROM

Non volatile Cannot be increased Read only Cannot be erased Permanent memory

(2(a). Give the application of RAM and

ROM Application of RAM

RAM stores the operating system and other system software that control maintain the computer and other devices.

RAM stores application programs that carry out a specific task e.g. Microsoft word,

RAM stores the data being processed by the application programs resulting information.

Application of ROM

Rom stores firmware written on by the manufacturers BIOS configurations which performs the POSTs are stored in the ROM chips

S3 CRE H/W TERM 1 2020 ANSWER ANY 2 QUESTIONS FROM 2 SECTIONS

SECTIOIN B:

ORDER AND FREEDOM

1. (a) How did God promote Justice in the Old Testament? (10 marks)

(b) What were the forms of injustices that existed in African traditional society? (10 marks)

2. (a) Point out the various ways in which leaders in Uganda abuse their leadership? (10 marks) (b) How did Rev. Ezekiel Apindi serve his society? (10 marks)

3. (a) In what ways can Ugandans demonstrate patriotism in the country? (10 marks) (b) Show how the Israelites showed disloyalty to God in the Old Testament? (10 marks)

SECTION C LIFE

4. (a) How is the fall of man in genesis 3 a source of man’s unhappiness in the Old Testament?

(10 marks) (b) Mention the occasions in African traditional society when Africans were happy? (10 marks)

5. (a) What are the causes of increasing death rates in Uganda Today? (10 marks) (b) How does the church remember those who died in the Christian faith? (10 marks)

6. (a) Explain the African traditional understanding of a successful person? (10 marks) (b) “The Uganda martyrs were remembered for having lived a successful life”. Why was this possible? (10 marks)

SECTION D:

MAN AND WOMAN

7. (a) Explain the factors responsible for the gross indiscipline of children today? (10marks) (b) What according to the bible is the ideal relationship between parents and children? (10marks)

8. (a) With examples, show how the government has improved the status of women in Uganda. (10 marks) (b) In what ways did Jesus promote equality during his time? (10 marks)

9. (a) Give reasons why some Christians are reluctant to take up holy matrimony today? (10 marks)

 

(b) As a Christian, what advice would you give such people? (10 marks) END

 

 

 

SENIOR THREE HOLIDAY WORK 

ENTREPRENEURSHIP EDUCATION 

1(a) What is a cheque?   (b) Explain the advantages of paying using a cheque.   (c) Explain the disadvantages of using a cheque.         

 

 

 

 

1  © TRISA 2020 

S3 GEOGRAPHY HOLIDAY WORK TERM ONE 2020

SECTION B: NORTH AMERICA Answer Two questions picking one from each region.

1a) Draw a sketch map of New England and on it mark and name:

i) Town: Boston, New Haven and New Bedford.

ii) Rivers: Connecticut and Merrimack.

iii) Potato growing areas.

iv) Tobacco growing areas. (08marks)

b) Describe the factors that favoured the development of the Agricultural sector in

New England. (06marks)

c) Explain the challenges facing the Agricultural sector in New England. (06marks)

d) Outline the steps being taken to address the challenges facing the Agricultural

sector in New England. (05marks)

2. Study table III below showing percentage for different land uses in British

Columbia and answer the questions that follow:

Table III: Land use in British Columbia

Land use Percentage

Cultivated land 01%

Rock mountain and Glaciers 56%

Agricultural 04%

Forests 39%

2  © TRISA 2020 

Total 100%

Source: MK Ordinary level Geography students Book 2 Pg. 263.

a) Draw a Pie-chart to show the relative importance of the different land uses in

British Columbia. (07marks)

b) i) Name three species of commercial trees in British Columbia’s forest.

(03marks)

ii) Describe the factors that favoured the development of the Forestry Industry in

British Columbia. (06marks)

c) Explain the problems facing the forest industry in British Columbia. (06marks)

d) Outline the steps being taken to solve the problems facing forestry in British

Columbia. (03marks)

SECTION C: THE REST OF AFRICA

Answer ONE questions in this part.

3. Study Fig. 1: Map of Africa provided and answer the questions that follow:

3  © TRISA 2020 

a)Name the:

i) Lakes marked A and B.

ii) Ocean marked 1.

iii) Rivers marked 2 and 3.

iv) Water falls marked C and D (07marks)

b) Describe the processes which led to the formation of any one waterfall named

in (a) (iv) above. (06marks)

4  © TRISA 2020 

c) Explain the benefits of the water fall chosen in (b) above to the people living in

the area. (08marks)

d) Outline the challenges facing the people living near rivers in Africa. (04marks)

4. Study table I. below showing climate of station A and answer the questions that

follow:

TABLE I CLIMATE OF STATION A

Months J F M A M J J A S O N D

Temp (0C) 30 31 31 30 29 28 28 28 28 29 30 30

R/F (mm) 25 25 50 100 275 500 900 925 700 300 125 25

Source: W.J. Means: A Geography of Africa Pg 37.

a) Draw a suitable graph to show the climate of station A. (09marks)

b) Calculate the:

i) mean annual rainfall of station A.

ii) Annual range of temperature for station A. (04marks)

c) Describe the climate of station A. (06marks)

d) i) State the Hemisphere in which station A is located. (01mark )

ii) Outline the economic activities that can be carried out around station A.

(05marks)

END

 

S3 History 

THE MAJI‐MAJI REBELLION (1905‐1907) 

CAUSES OF THE REVOLT: 

• Maji‐maji revolt was an African resistance against Germany colonial rule in Tanganyika. 

• The phrase maji‐maji means magic water which was to protect Africans against German bullets. 

• It involved several tribes like Ngoni, Zaramo,Ngindo,matumbi, pogoro, mbuga all from southern Tanganyika. 

• Maji‐maji rebellion occurred because the Germans disrespected African traditional leaders. 

• The Germans were arrogant to the Africans e.g they entered mosques with shoes and their dogs. 

• The rebellion occurred because Germans over taxed Africans. • The Germans annoyed Africans by replacing their their leaders 

with the cruel and harsh Akidas and Jumbes. • The Germans used Africans in forced labour on communal farms 

and public works. • The introduction of compulsory cotton growing scheme led to the 

rebellion. • The Germans grabbed the fertile land of Africans hence making 

the Africans landless which led to the revolt. • The Germans disrespected African customs and traditions eg their 

mercenaries raped Wangindo girls and women. • The Germans were harsh and brutal in their administration ie they 

mistreated Africans. • Africans wanted to regain their Independence from the Germans. 

• The influence of earlier rebellions like the Hehe rebellion led to Maji‐maji rebellion. 

• Africans like Ngoni wanted to revenge the Boma massacre of 1897  in which the Germans had killed many of them. 

• Brutal methods of collecting taxes that the Germans carried out led to the maji‐maji  rebellion of 1905‐1907. 

• Poor working conditions led to the rebellion. The Africans working for the whites were being subjected to sub‐ human working conditions. 

• The giving of asylum to a boy who slept with the Ngoni leader’s wife(chief Chambruma’s wife) led to the rebellion. 

• The introduction of Christianity led to the maji‐maji rebellion as it interrupted African culture hence annoying the people. Questions: 1.What were the causes of the 1905‐07 Maji‐maji revolt? 2. Why did the tribes of southern Tanganyika rebel in 1905‐1907? 3. Explain the causes of the African resistance against the Germans in 1905‐1907. 4.Why did Kinjikitile Ngwale rebel against German rule in 1905‐1907? 

       

Organisation/ Course of Maji‐maji revolt.  

• The revolt started in the area of Matumbi Hills in 1905. • It involved several tribes living in those areas like the 

Ngindo, mbunga, Ngoni, Zaramo, pogoro, matumbi and many others. 

• It quickly spread out to the cotton producing areas around R.Rufigi, Uruguru,Mahenge and to kilombero valleys. 

• The Mbunga, Ngindo, pogoro and the Ngoni were brought together by the traditional religion, the kalero cult. 

• Kinjikitile Ngwale encouraged the unity of the people by getting water from R. Rufigi and mixing it with sorghum flour. 

• This was alledly meant to protect them from the german bullets. 

• Kinjikitile Ngwale used whispers called Jijila to communicate with his fighters. 

• German plantations, mission stations, administration headquarters and Swahili shops were attacked. 

• They used surprise attacks when they invaded German headquarters of mahenge, Kilosa, Iringa and songea. 

• On 2nd august 1905, the coastal town of samanga was burnt and people especially government troops employed there were killed. 

• The Germans got re‐enforcement from the Zulu, Sudanese and Swahili mercenaries. 

• German re‐enforcement under Von wissman was later sent to put down the rebellion. 

• Africans then resorted to hit and run guerilla war fare in order to fight the mighty Germans. 

• Germans used the scorched earth policy in order to thoroughly defeat the rebels. 

• Africans were armed with rudimentary gadgets of war like water, spears and stones. 

• However, the magic water did not work and many rebels were killed and leaders too were executed. 

• Africans were defeated by the Germans in 1907 after the death of Mpandashalo. 

              Questions: 

1. How was the 1905‐1907 Maji‐maji resistance organized? 2. Describe the course of the maji‐ maji rebellion of 1905‐07. 

 

 

 

 

 

 

 

 

 

 

Why the maji‐maji rebellion was not successful. 

• Africans had poor weapons ie they were armed with traditional weapons like spears, arrows and stones. 

• Germans had skilled and well trained soldiers compared to the Africans. 

• Kinjikitile’s false propaganda of using magic water never protected Africans from German bullets. 

• Africans did not make enough preparations before the war. People just joined the rebellion basing on Kinjikitile’s propaganda without training. 

• There was lack of unity among various tribes e.g the Hehe, chagga and nyamwezi did not join the resistance. 

• The maji‐maji fighters lacked persistence e.g some tribes pulled out leaving fellow fighters to suffer at the hands of German forces. 

• The Germans used scorched earth policy e.g they destroyed African strength by burning down granaries, food stores, houses etc. 

• Africans had a poor economy which could not sustain the war. • Africans suffered from famine due to scorched earth policy. • Africans used poor fighting methods e.g direct military 

confrontation or open war fare. • The Africans lacked communication since Kinjikitile was far away 

in Ngarambe. • The Germans got re‐enforcement from the Zulu, Sudanese and 

the Swahili. • The Germans were determined to colonize Tanganyika. 

• The death of African leaders demoralized  fighters e.g abdalla mpanda and Kinjikitile. 

• Africans had been affected and weakened by slave trade. 

Questions: 

1. Why did the Maji‐maji resistance fail? 2. Why did Africans lose the war against the Germans? 

 

Effects of the Maji‐maji rebellion. 

• Many Africans lost their lives ie about 75000 Africans died hence depopulation. 

• Africans were defeated by the Germans. • Crops were destroyed leading to famine known as fugafuga. • Africans stopped violence and tried other peaceful means to 

regain their independence. • The Germans changed their methods of administration. • The Germans stopped taking Africans for granted. • Africans were encouraged to grow cash crops on their own. • Corporal punishments were stopped in Tanganyika. • White settler demands for forced labour were controlled. • The white settlers who mistreated Africans could also be 

punished. • Africans lost confidence and respect in their traditional rulers. • Africans lost confidence in traditional religions (magic water) • Many Africans joined foreign religions like Islam and Christianity. • There was economic decline in southern Tanganyika e.g 

agriculture and trade declined. 

• African collaborators were rewarded by the Germans. • There was destruction of property as a result of the war. • Tanganyika was divided into districts and rebellious areas were 

ruled by military rulers. • The rebellion was a source of inspiration to later nationalists e.g 

Julius Kambalage Nyerere. 

Question: 

1. How did the Maji‐maji rebellion affect the people of Tanganyika? 

2. What were the consequences of the maji‐maji revolt on the people Tanganyika? 

 

 

 

 

 

 

 

 

 

 

 

THE NANDI RESISTANCE(1895‐1906) 

Causes of the Nandi resistance: 

• The Nandi are a kalenjin speaking people who occupied the Highland escarpment west of Gishu plateau in Kenya. 

• They resisted the British because they did not want them to establish colonial rule in Nandi land. 

• The Nandi disliked the British interference and wanted to be independent of foreign rule. 

• They never wanted the British to cross their land. • The Nandi believed that they were militarily superior due to their 

experience in raiding their neighbours. • The Nandi also believed in their cultural superiority. • The Europeans were seen as female devils because of their colour 

and cloths by the Nandi. • The prophesy of their religious leader orkoiyot inspired the Nandi 

to fight the British. • They prophesied the coming of the “iron snake” which turned out 

to be the railway line. • The Nandi resisted from being thrown out of their land through 

which the railway had to pass. • The British settlers’ desire to occupy the same land through a 

forced peace treaty of kipture. • The Nandi resisted because they were being forced into reserves 

out of their land. • The killing of a British trader peter west sparked off the 

resistance. 

• The British killing of the Nandi leader Orkoiyot in a shameful incident forced the Nandi to fight the British. 

• The British were interfering with ivory and slave trade. • The Nandi resisted because their enemies the Masai and Abaluyia 

collaborated with the British. • They were also inspired by earlier rebellions like Abushiri and 

Hehe. 

Questions: 

(a) What were the causes of the 1895‐1906  African resistance against the British? 

(b) Why did the Nandi rise against the British between 1895‐1906? 

Why the Nandi resisted the British for so long: 

• The environmental advantage of a mountainous country with valleys which was ideal for guerilla war fare, favoured the Nandi. 

• The wet and cold climate caused respiratory diseases among the British and weakened them. 

• The Nandi practiced a mixed economy which reduced the effect of crop burning used by the British as they lived on their livestock. 

• The movement of the British troops was reduced by the large number of porters who had to carry food. 

• The Nandi had a highly disciplined and efficient army which had experience in war fare. 

• The Nandi had good military tactics that involved night fighting ambush for which the British were unprepared. 

• The Nandi did not have defensive strong points that would have been targets for the British guns. 

• The Nandi fought in separate units according to their clans or residence. 

• The Nandi made their own weapons like spears because they had knowledge about iron working. 

• The Nandi acquired guns through trade from the Arabs. • The Nandi never suffered from calamities like famine, diseases 

unlike other societies. • The British underestimated the strength of the Nandi forces and 

at first they sent small troops which the Nandi crushed. • The Nandi were determined to fight and defend their country. • The cutting of communication lines and railways hindered the 

transportation of British troops. • The Nandi had good leadership especially Orkoiyot Koitalel. 

Questions: 

1. Why did it take long for the British to defeat the Nandi? 2. Why were the Nandi able to resist the British for a long time? 3. Explain the reasons for the protracted nature of the Nandi 

resistance.   

 

 

 

 

S3 IPS‐ART HOLIDAY WORK 

 

With the use of illustration, explain any two methods of decorating a fabric.  

S.3 KISWAHILI 

HOLIDAY WORK. 

Andika insha ya mazungumzo kati yako na daktari. (write a dialogue between you and a doctor.)