MICROORGANISMS AND THEIR EFFECTS ON LIVING THINGS

SUBJECT: SCIENCE

FORM: 5

TOPIC: MICROORGANISMS AND THEIR EFFECTS ON LIVING THINGS

CLASSIFICATIONS OF MICROORGANISMS Type of microorganisms

Definition:

Tiny living things that cannot be seen by naked eyes, but can be seen by electron microscopes. They are also known as microbes.Some of microbes are harmful, but some of them are useful too

Classification:

There are 5 main groups for microbes:

a) Bacteria Beruk

b) ProtozoaPergi

c) Fungi

Filipina

d) Algae

Angkat

e) VirusesVan Characteristics of various type of microorganisms

1. Bacteria

Definition:

2nd smallest living things can be seen by electron microscope, have the simplest structure, and have the largest number among the five groups of microbes.Size:Consists only one cell (about 0.5 to 10 micrometer)

Shape:

There are four general shapes:

a) Cocci

Cium b) Bacili

Baboon

c) SpiriliaSampai

d) Vibrio

Vietnam

Structure:

Nutrition:

Some bacteria have chlorophyll, so they can make their own food by photosynthesis process. Some of bacteria dont have chlorophyll, so they have to be:a) Saprophytes - get food from decaying matters

b) Parasites- get food from other living organismsRespiration:Some of bacteria carry out aerobic respiration, and some of them carry out anaerobic respiration.

Reproduction:

a) By binary fissionb) By sporesHabitat:

Bacteria live in any damp places.

2. Protozoa

Definition:

Animals which are made up of only one cell. They are unicellular. Example: amoeba, paramecium and etc.

Size:

Consists only one cell (about 5 to 250 micrometer)

Shape:

Have various shapes, but mostly they have irregular shape (no fixed shape)

Structure:

Nutrition:

Some of protozoa live as parasites. E.g: plasmodium. Some of them obtain food from their surroundings. E.g: amoeba and paramecium. Some of protozoa make their own food.Respiration:

All of protozoa carry out aerobic respirationReproduction:

a) By binary fissionb) By asexual reproduction (spore formation)c) By sexual reproduction (conjugation)Habitat:

Protozoa live independently in any ponds, river, damp soils or in other organisms, and they lives in coloniesExercise:

1. Name the five main groups of microorganisms

2. Bacteria can live in unfavorable conditions. Under such conditions, they.

3. Label the part of bacteria below

4. Size of protozoa is about

5. What is the shape of paramecium? ............................3. FungiDefinition:

Plants which do not have chlorophyll. They include mushrooms, moulds and yeast. They do not have root, stems or leaves

Size:

Some of them are large (i.e mushroom), and some of them are tiny (i.e moulds and yeast)

Shape:

Have various shapes: i- round ball

ii- long filaments

iii- oval-shaped

Structure:

Nutrition:

Most of fungi live as parasites (i.e moulds) or saprophytes (i.e mucor) . Respiration:

Most of fungi carry out aerobic respirationReproduction:

a) By sporesFungi such a mushrooms form spores within their caps. Mucor form sporangium (containing spores). When it ripe, it bursts open and disperses the spore.

b) By buddingHabitat:

Fungi live in damp dark habitats.Example: Mucor grows on damp stale bread placed in the dark

4. AlgaeDefinition:

Very simple plants which have chlorophyll. Algae do not have root, stems or leavesSize:

Some of them are large (i.e seaweed), and some of them are tiny (i.e diatoms, euglena and etc)

Shape:

Have various shapes: i- round ball

ii- long filaments

iii- oval-shaped

iv- network-like structure

Structure:

Nutrition:

Algae possess chlorophyll, so that they can make their own food by photosynthesis. Respiration:

Most of fungi carry out aerobic respirationReproduction:

a) By asexual reproduction (binary fission)b) By asexual reproduction (fragmentation)Algae reproduced by breaking a long filament into two.

c) By sexual reproduction (conjugation)Habitat:

Algae live in fresh water, salt water, damp soil or on damp bark of trees.5. VirusDefinition:

Smallest microorganisms and it do not respire, do not excrete waste products, and do not possess nucleus, cell membrane and cytoplasm

Size:

About 0.02 0.4 micrometer, and can be seen only by electron microscope

Shape:

Have various shapes, maybe in spherical, rectangular or rod-shaped

Structure:

Nutrition:

Viruses live as parasites in living cell.Reproduction:

Reproduce only in living cells by making use of cellular components of living cells to make copies of itself.Habitat:

Viruses live only in living cell.Exercise:

1. How do fungi continue its generation under adverse condition?2. Why algae look greenish?

3. What a different between algae and tree?

4. Which of microorganisms cannot survive outside living cells?

A. Bacteria

C. Viruses

B. Algae

D. Protozoa

6. State 3 properties of viruses which are not characteristics of living things

FACTOR WHICH AFFECTS TO THE GROWTH OF MICROORGANISM

There are 5 main factors that affect the growth of microorganism:

1. NutrientsMicroorganisms need nutrient to live, and they get it by being:

a) autotrophic

b) saprophytic

c) parasitic

2. HumidityMicroorganisms need living place with high level of humidity. That means, they need moisture or water to live, and they will die if they do not get water for a period of time.

However, some bacteria can live in a place without waters presence by forming spores. For amoeba, they form cyst (spore with outer ring).3. Light

Most of virus, fungi and protozoa and some of bacteria prefer dim or dark habitat, while algae and few of bacteria tend to live in bright place since they have chlorophyll to carry out photosynthesis process.4. Temperature

Most suitable temperature for the microorganisms growth and live is about 37C (humans body temperature).

High temperature will kill microorganisms, while low temperature makes them inactive.

5. pH value

Most of microorganisms prefer to live in neutral medium (pH = 7)In very acidic (pH = 1 to 3) and very alkaline (pH = 12 to 14) conditions, most of microorganisms will be killed.

USEFUL MICROORGANISMS1. In the Digestion of FoodSome bacteria and protozoa help herbivores (e.g: rabbit, goat, cows and etc) and termites digest their food

They produce an enzyme called cellulose to help herbivores and termites digest cellulose into glucose

cellulose glucose2. In Decay

2.1 Formation of humusSome of saprophytic bacteria and fungi decompose organic matter into humus

2.2 Production of biogas and fertilizers

Some of saprophytic bacteria decompose organic waste (e.g: waste from oil palm, paddy and coconut) and turn it into methane gas

2.3 Disposal of oil spills

Some of bacteria break up oil spills and decompose it into less harmful substance.

3. In Medicine3.1 Antibiotics

There are 2 common antibiotics in world, which are:a) Penicillin (prepared from penicillium notatum bacteria) b) Streptomycin (prepared from streptomyces griseus bacteria)

Antibiotics can only kill bacteria

3.2 Vaccines

Vaccines are prepared from dead or very weak bacteria and viruses. It used to stimulate the body to produce antibodies.Vaccination refers to an injection containing certain vaccines that can prevent a person being infected to a certain disease. Example: BCG injection for dry cough disease.4. In Agriculture4.1 Maturing of tobacco leavesBacteria used to make tobacco leaves mature, so that they can emit desirable smell and taste.4.2 Nitrogen cycle

Figure 4.2- A (Simple nitrogen cycle)

4.3 Productions of chemicals from algae

Some algae used to produce beneficial chemicals for human beings. For the example:a) beta-carotene which has anti cancer properties

b) fatty acids which make cholesterol level in humans blood become low5. In Industry

5.1 Making breads and cakesYeast is used in the making breads and cakes. It is mixed with flour, sugar and water; and made into dough

Yeast will reacts with sugar to produce alcohol (ethanol), carbon dioxide and energy. By the way, this process is known as fermentation.

yeast + sugar carbon dioxide + ethanol + energyCarbon dioxide released makes the dough rise, so that breads and cakes become very soft.5.2 Making ethanolYeast is also used to produce alcohol (ethanol) instead of carbon dioxide.

5.3 Production of vinegar, and yoghurtVinegar (ethanoic acid) is prepared by using bacteria to change ethanol into ethanoic acid.

ethanol (alcohol) + oxygen ethanoic acid (vinegar) + waterYoghurt (contains lactic acid) is prepared by the action of bacteria on milk. Bacteria will reacts with lactose in milk and turns it into lactic acid.

lactose lactic acid5.4 Production of soy sauceSoy sauce is produced from the fermentation of a mixture containing mould, yeast, flour and soy beans. Salt is added to make it become salty.Exercise:1. List all factors affect to the growth of microorganism

2. Which microorganisms that can live in bright place?

3. Tell the range of air humidity which most of microorganisms are very active.

4. What is true about microorganisms?A. High temperature will kills microorganisms but low temperature will make them inactive

B. All microorganism grow faster in dry conditions

C. All microorganism cannot produce their own nutrients

D. All microorganism can be seen under light microscope

5. In which bacteria cultures in petri dishes A, B, C or D is the highest density of the bacteria colony?

Petri dishpHLightMoisture

A3 BrightMoist

B7BrightDry

C7DarkMoist

D10DarkDry

HARMFUL EFFECT BY MICROORGANISMS

- Microorganisms which can cause disease called pathogens. They can be either bacteria or viruses or fungi or protozoa.

- Before that, disease can be defined as any conditions which actively harm the normal functioning of the body.1. Diseases Caused by Bacteria DISEASEMETHOD OF INFECTIONSYMPTOMTREATMENT/PREVENTION

1.Tuberculosis

(Batuk kering)1. Through food

2. Through infected air breathed into the lung1. Patient loss weight and appetite for food

2. Patient coughs often, and in advanced he coughs out of blood.1. Can be treated by using antibiotics (i.e streptomycin and isoniazid)

2. Can be prevented through immunization by BCG vaccine

2. Cholera(Taun)1. Through contaminated water and food.1. Patient has severe diarrhoea and vomits

2. Patient feels giddy and pain in abdomen 3. His body becomes dehydrated.1. Patient given saline drip and antibiotic2. How to prevent from being infected?

i - Get vaccine

ii - Boil all drinking water

iii - Cover all food

iv - Increase the chlorine content in water supply

3. Gonorrhoea1. Through sexual intercourse1. For male, his testis becomes inflamed and enlarged. He feels pain during urination.

2. For female, she has painful vagina and uterus.1. Can be treated by using antibiotics (i.e penicillin)2. Can be prevented by avoid having sex with prostitutes.

4. Syphillis1. Through sexual intercourse1. Patient has fever and non-itchy rash on the body.2. Patient has sores on the penis or vagina

3. Patient has sore throat and pain in the bones and joint.1. Can be treated by using antibiotics (i.e penicillin)

2. Can be prevented by avoid having sex with prostitutes.

5. Tooth decay1. Through foods waste on the teeths surface.1. Patient feels pain for infected teeth since teeths pulp is badly inflamed1. Can be prevented by:I - Having a diet low in sugars

ii - Wash your mouth and brush your teeth after eating.

Table 9.4 A (Diseases Caused by Bacteria)2. Diseases Caused by Viruses

DISEASEMETHOD OF INFECTIONSYMPTOMTREATMENT/PREVENTION

1.Common cold(Selsema)1. Through contaminated air (when people around sneezes)1. Patient gets cough, fever, running nose and red or watery eyes2. Patient has a sore throat3. Patient becomes weak1. NO PROPER TREATMENT2. Can be prevented by:

i - having proper dietii - have fresh and clean air

iii- keep away from the crowd

2. Dengue fever(Demam denggi)1. Through Aedes mosquito (inject the virus into patients blood)1. Patient has high fever.2. Bleeding in nose and gums3. Pain in the bones, joints, muscles and eyes

4. Blue marks appear on the body 1. NO PROPER TREATMENT2. How to prevent from being infected?

i - Keep our living place cleanii - Destroy Aedes mosquitos habitatiii - Fogging

3. AIDS(Acquired Immune Deficiency Sydrome)1. Through 3 ways:i -Sexual intercourse

ii - Sharing of syringes during drug addicts

iii- Infected pregnant woman to her baby.1. Patient has fever and diarrhoea, and coughs very often.2. Patient has loss appetite for food and weight.1. NO PROPER TREATMENT2. Can be prevented by having healthy clean life.

Table 9.4 B (Diseases Caused by Viruses)

Life Cycle of Aedes Mosquito3. Diseases Caused by FungiDISEASEMETHOD OF INFECTIONSYMPTOMTREATMENT/PREVENTION

1.Tinea

(Panau)1. Through spore of the fungus1. Whitish patches appears on the infected skin (usually face or back of the body)

1. Can be treated by suitable anti-fungal drugs

2. Can be prevented by:

i - keep the body clean and dry

ii - avoid direct contact with infected person .

iii - do not share towel or comb

2. Ringworm

(Kurap)1. Through spore of the fungus1. A reddish area appears on the infected skin

2. Infected skin becomes itchy 1. Can be treated by suitable anti-fungal drugs

2. Can be prevented by:

i - keep the body clean and dry

ii - avoid direct contact with infected person .

iii - do not share towel or comb

Table 9.4 C (Diseases Caused by Fungi)

4. Diseases Caused by Protozoa

DISEASEMETHOD OF INFECTIONSYMPTOMTREATMENT/PREVENTION

1.Malaria

(Demam kepialu)1. Through Anopheles mosquito (inject parasitic protozoon plasmodium into blood)1. Patient has high temperature at intervals2. After fever, patient feels very cold and shivers.

3. Got rapid pulse rate

4. Got very liitle urine, which is very yellow.1. Can be treated by suitable drugs such as plasmoquine, quinine, or chloroquine2. Can be prevented by:

i - foggingii - Keep our living place clean

Table 9.4 D (Diseases Caused by Protozoa)

5. The Transmission of Diseases

- Diseases transmitted from one person to another by FIVE ways:

i- By Air

It occurs when infected person sneezes, coughs or talks. So, a spray or tiny droplets of moistures containing pathogens released into airDiseases transmitted by air: common cold and tuberculosis

ii- By Water

It occurs when water from ponds, river and sea always contaminated with faeces which usually contains pathogens. So, these pathogens can spread into water supplies due to unsanitary conditions / seeped through the soilDiseases transmitted by water: cholera and hepatitis A

iii- By Food

It occurs when food contaminated by pathogens due to unhygienic handling or houseflies presence.Diseases transmitted by food: cholera, food poisoning and hepatitis A

iv- By Contacts

It occurs when there has direct contact between infected people to others or wity objects handled by infected peopleDiseases transmitted by contacts: tinea, ringworm, AIDS, gonorrhoea and syphilis

v- By VectorVectors: Animals carry pathogens in their bodies. For example: Aedes mosquito, houseflies, rats, dogs and etcDiseases transmitted through their bite into humans blood or carrying pathogen onto the food.

Diseases transmitted by vectors: dengue fever, malaria and cholera PREVENTION OF DISEASES CAUSED BY MICROORGANISMS

1. Prevention through the Control of Vectors

Common vectors, their pathogens and diseases transmitted by them can be shown as following table:

VectorPathogen Disease

Aedes mosquitoVirusDengue fever

Anopheles mosquitoProtozoa (plasmodium)Malaria

HouseflyBacteriaCholera

RatsFleasPlague

Table 9.6 A (Vectors and its diseases)1.1 Control of Houseflies

To control houseflies, we must:a) Keep our surrounding cleans

b) Cover our foods

c) Throw organic waste into plastic bags and tied it up for disposal

d) Spray insecticides to keep away the adult fly away

e) Keep manure and compost heaps far away from houses.

1.2 Control of MosquitoesTo control mosquitoes, we must:

a) Drain marshes and unused ponds

b) Clean the house from opened empty tins and coconut shells

c) Put anti-larva chemicals or into ponds, drains and stagnant waterd) Carry out fogging around living places

e) Fix wire gauze at doors and windows

f) Sleep under a mosquito net

2. Prevention through Sterilization

Definition of Sterilization:

Destruction of pathogens and their spores in a substance or object

Type of sterilization:

a) Heatb) Chemicalsc) Radiation2.1 Sterilization using Heata) Boiling

- Boiling a substance or an object in water for 20 minutes will kill all bacteria cells and many spores.- Surgical instruments in clinics or hospital are usually sterilized in this way.

b) Autoclave

- An autoclave is a steam sterilizer. The things to be sterilized are kept in closed container and steam under high pressure and temperature of 120C for 15-20 minutes- All the bacteria and spores will be destroyed in this way.

c) Dry air oven

- It can be used to sterilize glassware and metal objects. - The things to be sterilized are kept in dry air oven at 170C for 15-20 minutes

- Effectiveness of sterilization using this way is less compare to using autoclave.

2.2 Sterilization using Chemicals

a) Antiseptics

- It can be used to prevent the growth of some bacteria and destroy some others.- It usually used for cleaning wounds - Example: iodine solution, hydrogen peroxide solution and potassium manganate (VII) solution

b) Disinfectants

- Powerful chemicals to destroy pathogens

- It used for sterilizing instruments, containers, cloths, floors, walls and etc.- Example: lysol, formaldehyde, phenol and sodium hypochlorite 2.3 Sterilization using Radiation

a) UV light - Applied to lamp in surgical operating theatre and lab for air sterilizing.

b) Gamma rays

- It used for sterilizing surgical instruments and certain foods

- Foods that have been sterilized in this way can be kept for a long period of time and it is safe to eat.3. Prevention through Immunization

Definition of Immunization:

Process of increasing a persons resistance to a particular infection by using antibodies

Definition of Antibodies:

- Chemical substance produced from white blood cells to destroy pathogen or neutralize the toxins produced by pathogen. Each of antibody acts on a particular pathogen.

Type of immunity:

a) Natural- Refer to situation when a person recovered from an infection, antibodies produced by the persons body to fight that infection remains in the persons blood for months or even for his/her whole life.

- When same infection comes back again, the person has antibody to fight back

b) Artificial- Refer to a situation when a person given a vaccination, injecting a dead or weak pathogens into the persons body to stimulate his/her body to produce antibody

- Artificial immunity also can be gained when a person is given an injection contains antibody.

c) Passive - Part of artificial immunity

- Can be done by injecting antibody (usually contains antiserum) directly into a persons body

- Effect of this immunity is fast but temporary.

d) Active- Can be either natural or artificial immunity

- Can be done by having antibody after recover from infection or vaccination

- Effect of this immunity is slow but permanent.

TREATMENT OF DISEASES CAUSED BY MICROORGANISMS

1. Antibiotics

2. Antiserum

3. Chemotherapy

4. Radiotherapy

5. Surgeryenzyme

cellulase

Nitrogen-fixing bacteria

Denitrifying bacteria

Nitrogen gas

Plant and animal proteins

Nitrates

Nitrifying bacteria

Bacteria of decay

Ammonium compounds

enzyme

zymase

bacteria

bacteria

Egg are laid singly in stagnant water

Egg are hatched and becomes larva

Adult mosquito has black stripes on the abdomen and legs

Larva grows and becomes pupa