Biological Molecules
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- Created by: ellie_tayton
- Created on: 18-02-16 11:01
Carbohydrates
- Found in Pasta, Rice and Sugar
- Provide Energy
- Made up of simple sugars
- Contains the elements Carbon, Hydrogen and Oxygen
- Starch and Glycogen are large complex carbohydrates
- Smaller units are glucose and maltose
- Test for glucose-Use benedicts reagent
- Benedicts reagent starts blue and will go green, yellow, orange and brick red.
- The more glucose present the more towards the brick red the colour.
- Test for starch-Iodine solution
- Positive test= Orange to Blue/Black
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Proteins
- Made up of long chains of amino acids
- Contain the elements Carbon, Nitrogen, Hydrogen and Oxygen
- Found in meat and fish products
- Needed for Growth and repair to provide energy in emergencies
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Lipids
- Found in dairy products and oily fish
- Provides energy
- Acts as an energy store
- Provides insulation
- Made of Fatty acids and Glycerol
- Contain Carbon, Hydrogen and Oxygen
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Nutrients
- Vitamins A, C and D
- Vitamin A found in liver-improves vision and keep your skin and hair healthy
- Vitamin C found in citrus fruits-prevents scurvy
- Vitamin D found in eggs-needed for calcium absorption
- Calcium and Iron
- Calcium found in dairy products-needed to make bones and teeth
- Iron found in red meat-needed to make haemoglobin for healthy blood
- Water-all bodily functions need water to be able to function
- Water is easily lost via sweating, breathing and urinating
- Dietary fibre found in wholemeal bread- aids the movement of food through the digestive tract
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Energy from Food
- To see how much energy food contains we can do a calorimetry experiment
- Burn food under boiling tube full of water
- Take tempereature of water at the start and the end
- Calculation= Energy in Food (J) =Mass of Water (g) x Temperature change (C) x 4.2
- Energy per gram of food = Energy in food/Mass of food
- To Improve the acuracy of this experiment you can wrap the boiling tube in foil to minimise heat loss
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Enzymes and Digestion
- Starch, Proteins and fats are large insoluble molecules.
- They need to be broken down into smaller soluble molecules to pass through the wall of the intestines in the digestive system
- Amylase converts Starch into Maltose
- Maltase converts Moltose into Glucose
- Proteases converts proteins into Amino acids
- Lipases converts Lipids into Glycerol and Fatty Acids
- Bile is produced in the liver and stored in the gall bladder
- Bile neautralises stomach acid and emulsifies fats
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The Digestive system-The Alimentary Canal
- Includes the mouth, the oesophagus, the stomach, the small intestine, the large intestine, and the anus
- Other organs involved are: The liver, the gall bladder and the panreas
- Mouth-Teeth grind food
- Saliva produced, saliva contains amylase
- Oesophagus-connects mouth to stomach
- Uses peristalsis to push food along (muscular contractions to squeeze the food)
- Stomach-contains hydrochloric acid which kills bacteria and gives the right pH for enzymes to work
- Contains the enzyme pepsin (which is a protease)
- Small intestine- Produces Protease, Amylase and Lipase to help digestion
- This is where absorption of nutrients takes place
- Large intestine-This is where water is absorbed from food
- Anus- Any food not digested is expelled here as faeces
- Pancreas- Produces Protease, Amylase and Lipase to be released into the small intestine
- Liver- Where Bile is produced
- Gall Bladder- Where Bile is stored before being released into the small intestine
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The 5 main stages of Digestion
- Ingestion- Taking food into the body
- Digestion- Break down of food in the body, this can be mechanical and chemical
- Absoption- Digested food absorbed into the body
- Assimilation- The digested food is used by the cells in the body
- Egestion- Anything not used is got rid of by the body
Villi in the small intestine help with absorption of nutrients
- They have a large surface area
- They are covered in microvilli to help increase surface area
- They have blood vessels to help absorption of nutrients into the blood stream
- The walls of the villi are thin to help diffusion of small molecules
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