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Food tests
Food type
• Protein
• Sugar
• Fat
• Carbohydrate
Test
• Biuret turns purple if protein is present
• Benedicts turns from blue to red/brown if sugar is present
• Greaseproof paper gets an oily residue
• Iodine turns blue/black if starch is present
Carnivore
• Only eats meat– E.g. Spider, lion
• Its survival is dependent on finding and catching prey
Top predator – Nothing eats him!
Carnivore Teeth Adaptation
Herbivore
• Only eats plants– E.g. Cow, aphid
• Depends on a large supply of plant matter.
• Longer gut as less energy available in their food.
Herbivore Teeth Adaptation
Omnivore
• Eats a mixture of plants and animals– E.g. Pigs, humans
• Increased chance of survival as they are not restricted to one diet.
Decomposers
• Breaks down and recycles dead material.– E.g. Bacteria, fungi
Primary Producers (Plants)
• Plants can make their own food using– Sunlight– Chlorophyll– Water– Carbon dioxide
• How are all the consumers and producers linked?
3 main functions
of digestive system
Digestionbreaks down
food into molecules
body can use
Absorptionmolecules absorbedinto blood & carried thru. body
Eliminationwastes
eliminatedfrom body
2 kinds of digestion
mechanical chemical
food ground intosmall pieces
large food moleculesbroken small
molecules by enzymes
Path of digestion
The Digestive System
• Mouth• esophagus• Stomach• Small Intestine• Liver• Large Intestine• Gall Bladder• Pancreas• Rectum• Anus
Let’s find out what happened to your breakfast today!
(Breaking food down into smaller pieces)
1. mouth- releases saliva- moistens food
• chemical digestion:enzyme- protein
speeds chemical reactions
• mechanical digestion- teeth
Mouth• Teeth
(mechanical breakdown)– Incisors used for cutting
– Canines used for stabbing and holding
– Molars large surface area used for grinding
• Saliva
(chemical breakdown)– Enzyme (speeds up
reactions in the body)
– Breaks down carbohydrate
2. esophagus
• muscular tube - connects mouth stomach
• lined w/ mucus
flap of tissue that seals off windpipe-prevents food from entering lungs
2. esophagus
• peristalsis= involuntary waves of muscle contractions that move food stomach
esophagus
• Approximately 25cm long
• Moves food from the throat to the stomach– Muscle movement
called peristalsis
• If acid from the stomach gets in here that’s heartburn.
3. stomach-• most mechanical digestion occurs here
• some chemical digestion
–enzymes- pepsin
–hydrochloric acid
Mechanical digestion in the stomach
is like the clothes and soapy water
mix in a washing machine.
YouTube video-digestion
Stomach
• Stores the food you eat
• Chemically breaks it down into tiny pieces
• Mixes food with digestive juices
• Acid in the stomach kills bacteria
small intestine• most chemical digestion & absorption takes place here
• receives bile
small intestine
• lined with villi= –absorb nutrient molecules
Millions of tiny finger shaped structures called villi (villus) cover the surface of the small intestine.
Small Intestine
• Small intestines are roughly 6 metres long.
• Enzymes and bile are added.
• Villi increase the surface area to help absorbtion.
• Nutrients from the food pass into the bloodstream through the small intestine walls.
liver• in upper portion of abdomen• makes bile= breaks up fat
Liver
• Directly affects digestion by producing bile– Bile is an enzyme that
helps dissolve fat
• Processes nutrients in the blood, filters out toxins and waste.
• Is often called the body’s energy factory
gallbladder
• stores bile
Gall Bladder
• Stores bile from the liver
• Delivers bile when food is digested
• Fatty diets can cause gallstones
pancreas• between
stomach & small intestine
• produces enzymes - break down starches, proteins & fats
Pancreas
• Produces compounds to digest fats and proteins
• Neutralizes acids that enter small intestine
• Regulates blood sugar by producing insulin
large intestine• last part of digestive
system• contains bacteria that
make Vitamin K• absorbs water • eliminates remaining
material
large intestine
•ends in short tube-rectum
Large Intestine
• About 1.5 metres long• Accepts what small
intestines don’t absorb.
• Absorbs water and minerals from the waste matter.
• Absorption means taking into the body via the blood stream.
anus• muscular opening @ end of rectum
Rectum and Anus
• Rectum– About 15cm long– Stores waste
before egestion.
• Anus– Muscular ring that
controls egestion.
gallbladder
liver
large intestine
small intestine
stomach
anus
esophagus
mouth
epiglottis
appendix
Write the name of each colored organ:
• Green:• Red:• Pink:• Brown:• Purple:• Green:• Yellow:
Answers
• Green: Oesophagus• Red: Stomach• Pink: Small Intestine• Brown: Large Intestine• Purple: Liver• Green: Gall Bladder• Yellow: Pancreas
What are nutrients?• Essential substances that your
body needs in order to grow and stay healthy
• Six categories of nutrients:• Carbohydrates• Fats• Proteins• Vitamins• Minerals• Water
6 Key Nutrients
• Carbohydrate
• Fat
• Protein
• Vitamins
• Minerals
• Water
• C ould • F anny
• P lay
• V iolin
• M uch
• W orse
Energy content of food
1 gram of carbohydrateequals 4.15kcal of energy
EnergyBUTTER
1 gram of fatequals 9.4kcal of energy
1 gram of proteinequals 5.65kcal of energy
Energy efficiency
gases
Energy used
Heat
urine
faeces
No animal is able to utilise all the energy in its food !
Energy Needs
• Body Size
• Body composition
• Degree of exercise
• Physiological state and
• Ambient temperature
Carbohydrates
• All carbohydrates are composed of carbon, hydrogen, and oxygen in a 1:2:1 empirical ratio.
• The general empirical formula for a carbohydrate is CH2O.
If a carbohydrate has 5 carbons atoms, what would be its empirical formula?
If a carbohydrate has 12 hydrogen atoms present, what would be its empirical formula?
CC55HH1010OO55
CC66HH1212OO66
Carbohydrates• Structure and function: Carbohydrates are
sugars and starches that the body uses for ENERGY!
• PLANTS are the major source of carbohydrates in the food we eat.
Simple Carbohydrates
• Sugars that are quickly digested and provide a BOOST of energy for the body
• Foods with LOTS of sugar: oranges, milk, cookies, candy
• 1
Carbohydrates
Complex Carbohydrates• Starches that are composed of
many sugars linked together
• They provide the body with long-term energy since they are digested more slowly than sugars.
• Foods with LOTS of starch: rice, beans, potatoes
• 1
Carbohydrates
1. JOBS OF CARBOHYDRATES
ENERGY = major jobprovides 4 calories per gram
Not enough carb’s eaten = lose weight
Too many carb’s eaten = gain weight
“Fiber” in foods is another part of the carbohydrate family.
**Fiber, or cellulose, does not completely digest
We need it to: 1. help the body digest other foods and
2. to help eliminate waste-- (NATURE’S BROOM) Examples of fiber are: “strings” in celery, pulp of oranges,
peel of apples, etc.
Have You Had Your Fiber Today?
Nutritional concernsof lack of carbohydrates in diet
symptoms = TIRED
Functions:• ENERGY source for the body
(more than carbs and proteins)• Help protect and cushion vital
organs as well as joints • Insulate the body
.• 1
Fat
JOBS OF FAT
• 1. ENERGY – 9 CALORIES PER GRAM
• 2. PROVIDE BODY HEAT, INSULATE• 3. CARRIES FAT SOLUBLE
VITAMINS TO THE CELLS• 4. ADD FLAVOR TO FOOD• 5. SATIETY VALUE = makes you feel
full longer
Unsaturated fats:
• At room temperature, they are typically in liquid form.
• They are less harmful to the circulatory system than saturated fats.
• Foods with a lot of unsaturated fat: canola, safflower, and peanut oils
• 1
Fat
Saturated fats:
• At room temperature, they are typically in solid form.
• Diets with TOO MUCH saturated fat have been known to cause heart disease.
• Foods with a lot of saturated fat: beef fat, egg yolks, dairy products
• 1
Fat
FAT is both a nutrient and a food—butter on bread is an
example of eating fat.
Fat is sometimes “hidden” in food—examples: salad
dressing, gravy, sour cream, cookies, pies, cakes
Saturated fat is SOLID at room temperature. (notice S’s in
saturated and solid—a clue to help you remember!)
Unsaturated fat is LIQUID at room temperature.
Fat food sources
butter, lardfat present in meat
baconoils of all kinds
egg yolksdairy foods
• 1
ProteinProteins
• Function: Provide the building materials your body needs to grow and repair itself
JOBS OF PROTEIN
• BUILD AND REPAIR BODY TISSUE is the main job.
• Energy— 4 calories per gram
(What other nutrient also provides 4 calories of energy per gram?)
CARBOHYDRATES
What is a calorie?• The energy obtained from
carbohydrates, proteins, and fats is measured in units called calories.
Calories
Food
Type
• Carbohydrate
• Fat
• Protein
• Sugars
Use
• Long term energy
• Protecting organs and long term energy store
• Making muscle, enzymes, skin, hair
• Fast energy
Vitamins and Minerals
Vitamins and minerals are essential for the maintenance of good health and the prevention of a number of diseases.
Vitamins
Vitamins are naturally occurring organic compounds that are essential to metabolic or other functions in the body.
Most vitamins cannot be synthesized by the body. They must be supplied in the diet.
Vitamins are usually classified as water soluble or fat soluble
Minerals
Minerals are inorganic and are found in the soil and water absorbed by plants or eaten by animals.
The human body requires substantial amounts of minerals on a daily basis to ensure proper functioning of the organs, bones, tissue and immune system.
Minerals
• Macro-minerals
• Trace Minerals
MineralsMineral What the mineral does Food sources
Sodium Fluid and electrolyte balance, supports muscle contraction and nerve impulse transmissions
salt, soy sauce, bread, milk, meats
Chloride Maintains fluid and electrolyte balance, aids in digestion
salt, soy sauce, milk, eggs, meats
Potassium Maintains fluid and electrolyte balance, cell integrity, muscle contractions and nerve impulse transmission
potatoes, vegetables, banana, strawberries, cod, milk
Calcium Formation of bones and teeth, supports blood clotting
milk, yogurt, cheddar cheese, Swiss cheese, tofu, sardines, green beans, spinach, broccoli
Phosphorus Formation of cells, bones and teeth, maintains acid-base balance
all animal foods (meats, fish, poultry, eggs, milk)
Magnesium Supports bone mineralization, protein building, muscular contraction, nerve impulse transmission, immunity
Green vegetables, tomato juice, beans, cashews, halibut
Iron Part of the protein hemoglobin (carries oxygen throughout body's cells)
spinach, broccoli, green beans, tomato juice, beef liver
MineralsMineral Function Food sources
Zinc Enzymes production of genetic material/proteins, vitamin A transport, wound healing, sperm production and the normal development of the fetus
Green vegetables, tomato juice ,lentils, oysters, shrimp, crab, meats yoghurt, cheese
Selenium Antioxidant, works with vitamin E to protect body from oxidation
seafood, meats and grains
Iodine Thyroid hormones regulate growth, development and metabolic rate
salt, seafood, bread, milk, cheese
Copper Absorption/utilization of iron, formation of hemoglobin , enzymes
meats, water
Manganese Facilitates many cell processes widespread in foods
Fluoride formation of bones and teeth, helps to make teeth resistant to decay
fluoridated drinking water, tea, seafood
Chromium Associated with insulin and is required for the release of energy from glucose
vegetable oils, liver, whole grains, cheese, nuts
Molybdenum Facilitates many cell processes legumes, organ meats76
Vitamin Characteristics
• Each vitamin has one or more specific purposes.
• Vitamins are essential to life processes. • Vitamins are generally used by the body with
very minimal changes• Vitamins are usually required in only small
amounts • Most vitamins cannot be synthesized by the
body directly
77
Important VitaminsVitaminVitamin FunctionFunction SourceSource
A A RetinolRetinol
Supports vision, skin, bone and Supports vision, skin, bone and tooth growth, immunity and tooth growth, immunity and reproductionreproduction
mango, broccoli, butternut mango, broccoli, butternut squash, carrots, tomato squash, carrots, tomato juice, sweet potatoes, juice, sweet potatoes, pumpkin, beef liverpumpkin, beef liver
C C Ascorbic AcidAscorbic Acid
Collagen synthesis, amino acid Collagen synthesis, amino acid metabolism, helps iron metabolism, helps iron absorption, antioxidantabsorption, antioxidant
Fruits and vegetablesFruits and vegetables
DD Promotes bone mineralizationPromotes bone mineralization Self-synthesis milk, egg Self-synthesis milk, egg yolk, liver, fatty fishyolk, liver, fatty fish
B12B12 New cell synthesis, Breaking New cell synthesis, Breaking down fatty acids / amino acids, down fatty acids / amino acids, nerve cell maintenancenerve cell maintenance
Meats, poultry, fish, Meats, poultry, fish, shellfish, milk, eggsshellfish, milk, eggs
EE Antioxidant, regulation of Antioxidant, regulation of oxidation reactions, supports cell oxidation reactions, supports cell membrane stabilizationmembrane stabilization
Shrimp, codShrimp, cod, , wheat wheat germ, tofu, germ, tofu, polyunsaturated polyunsaturated vegetable oils, sweet vegetable oils, sweet potatoes, potatoes,
KK Synthesis of blood-clotting Synthesis of blood-clotting proteins, regulates blood calciumproteins, regulates blood calcium
Liver, leafy green vegetables, Liver, leafy green vegetables, spinach, broccoli, cabbage, spinach, broccoli, cabbage, 78
Vitamin C Sources• Vitamin C is found in many
fresh fruits and vegetables. • . Cooking vegetables in water
tends to leach the vitamin from the food.
• Cooked foods also contain less vitamin C, since it is also easily oxidized and hence destroyed in the cooking process.
• Aid in healing wounds and helping to prevent bacterial infections
79
Vitamin C Deficiencies
• Scurvy or Scorbutus.
• Symptoms include 1. swollen legs,
2. rotting gums,
3. and bloody lesions. • Common among sailors in
the 18th and 19th centuries who spent a long time at sea without fresh fruits and vegetables
80
Vitamin A Sources• Commonly found in cod liver oil, green vegetables,
and fruit. • Carrots indirectly serve as a source of vitamin A
since they contain carotene which the body readily converts to vitamin A
81
Vitamin A Functions• Vitamin A is fat soluble.• It is not readily broken down by cooking.• Role in aiding in night vision.
82
Vitamin A Deficiencies• A deficiency in vitamin
A results in night blindness.
• The most serious deficiency results in a condition known as Xeropthalmia, a severe form of conjunctivitius or blindness.
83
Vitamin D - Sources • Vitamin D is commonly found in fish liver oil as
well as egg yokes. • Unlike other vitamins, the body synthesizes
vitamin D in the skin through the action of ultraviolet light
Vitamin D Functions • Vitamin D is an important regulator of
calcium metabolism. • It is involved in the uptake of calcium and
phosphate ions from food into the body. • It is necessary for the proper formation of
bone structures and teeth.
Nutrional DeficienciesNutrional deficiencies diseases in children often result from a lack of protein
MarasmusMarasmus
KwashiorkorKwashiorkor
KwashiorkorKwashiorkor is a specific wasting away often occurring in infants at weaning. It results from a lack of protein in the diet
MarasmusMarasmus is a wasting away of the body tissues from the lack of calories as well as protein in the diet. The child is fretful rather than apathetic and is skinny rather than swollen with edema.
The Ugly Face The Ugly Face of “Hidden of “Hidden Hunger”Hunger”
Zinc Deficiency
Vitamin A Deficiency Iodine Deficiency
Iron Deficiency
Ca DeficiencyRickets
(Map from USAID)
Global Micronutrient Global Micronutrient DeficienciesDeficiencies
> 3 billion people afflicted
> 200 million children affected
Map from WHO
Prevalence of Vitamin A DeficiencyPrevalence of Vitamin A Deficiency