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BIOLOGY: Nutrition and Digestion - Coggle Diagram
BIOLOGY: Nutrition and Digestion
Nutrients
Nutrients are important substances which your body needs to survive and stay healthy
Fibre
Used for aiding digestion. Not exactly a nutrient but important for body. Found in sweetcorn, bread and pasta
Protein
Used for tissue and cell repair and growth. Found in meat, fish, eggs, seeds and nuts
Carbohydrates
Used on a daily basis as energy source. Simple carbs provide quick burst of energy whereas complex ones provide controlled energy. Found in sweets, chocolate, bread, pasta and potatoes
Vitamins and minerals
Vitamins are needed for chemical reactions to occur in the cells. Minerals are used to make bones strong and they also help the blood carry oxygen.
Water
Hydrates and cleanses body. All chemical reactions in the body take place in the body. 75% of body is water. Found in soups, watery drinks and water
Fats
Used as a backup energy reserve. Found in oils, butter and fatty foods. Saturated fats are bad for you and unsaturated fats are better for you. Saturated fats are found in butter and cream. Unsaturated fats are found in olive oil and nuts.
Food Tests
Test for starch
Reagent: Iodine, Colour before: orange brown, Positive result: Blue/black
Test for Protein
Reagent: Biuret's Reagent, Colour before: Light blue, Positive result: Purple
Test for Fats
Reagent: Ethanol and water, Colour before: colourless, Positive result: Milky white
Test for sugar
Reagent: Benedict's reagent, Colour before: Bright blue, Positive result: Orange. *Solution must be heated to work. Preferably in a water bath
Deficiency diseases
Deficiency: Lack of a certain nutrient in a diet
Malnutrition: Not enough nutrients in a diet
Diseases
Scurvy: Lack of vitamin C
Symptoms: Black gums and rotting teeth, bad breath, fatigue and nausea
Kwashiorkor: Lack of protein
Symptoms: swollen belly, lack of muscle growth, lethargy
Anemia: Lack of iron
Symptoms: lethargy, shortness of breath, headaches
Soft bones: calcium deficiency
Enzymes
Carbohydrase: Breaks down carbohydrates into glucose. Needs saliva or neutral conditions to work. Amylase is a type carbohydrase
Protease: Breaks down proteins into amino acids. Protease needs stomach acid to work as it only works in acidic conditions
Lipase: Breaks down fats into glycerol and fatty acids. Helped by bile (made in the liver) and it needs neutral conditions
Enzyme: A special protein which speeds up reactions and breaks down large nutrients into soluble and absorbable molecules. They are biological catalysts
Enzymes are made in the pancreas and small intestine
Bacteria
Good bacteria prevent pathogenic(bad) bacteria from growing
Some gut bacteria also help break down food
Some even make enzymes
Digestive system
Stomach: Breaks down food mechanically and chemically using stomach acid. Kills any bacteria in the food
Small Intestine: Absorbs most nutrients in the food.
Large Intestine: Absorbs water and fluids.
Mouth: Food enters the body here and it is mechanically and chemically broken down using teeth, tongue and saliva
Gullet: Food travels down the gullet to the stomach through peristalsis
Anus: Faeces leave the body here
Rectum: Faeces are stored here
During digestion, large nutrients are broken down and absorbed by the body
Liver: Bile is made here and stored in the gall bladder. Bile works with lipases to break down fats.
Pancreas: Enzymes are made here
Energy in food
Energy in food is measured in joules and kilojoules
Your daily energy requirement depends on what you do every day. If you take in more or less energy than you need, you will either be overweight or underweight
For example, the more exercise you do, the more energy you need