Topic 2 - Food and Digestion

• What chemical elements are present in Carbohydrates 


  Carbon

  Hydrogen

  Oxygen
• What chemical elements are present in Lipids


  Carbon

  Hydrogen

  Oxygen
• What chemical elements are present in Proteins


  Carbon

  Hydrogen

  Oxygen

  Nitrogen

  Sulfur
• What are starch and glycogen made up of


  Simple Sugars
• What are proteins made up of


  Amino Acids
• What 2 molecules are lipids made up of

  Glycerol and Fatty Acids
• Function of Carbohydrates 


  The body's main source of energy
• Function of Proteins


  Different roles and can be used as hormones, enzymes, antibodies, etc
• Function of Lipids


  Store energy, Insulate and form cell membranes
• Test for Starch


  Drop yellow-brown iodine on a sample of Starch, forming a very dark blue or 'blue-black' colour
• Test for Glucose


  Small spatula of glucose is placed in a test tube where 2 drop of water is added. Drops of Benedict's solution is added to make the mixture blue. A water bath in a beaker is then heated up using a Bunsen burner. The colour will gradually change forming a 'cloudy orange' or a 'brick-red'
• Test for Protein


  A little protein is placed into a test where 2 drops of water is added. We then add drops of biuret solution. A purple colour should appear.
• Test for Lipids (Fats)


  Rub a food sample onto a piece of paper and leave to dry. A translucent stain round the sample when held up to the light should appear.
• Why is a balanced diet important?


  The body needs different substances in different proportions to function properly. Too much or too little of different things can be harmful
• What are the 7 groups that we need for a balanced diet?

  Carbohydrates

  Proteins

  Fats

  Vitamins

  Minerals

  Fibre

  Water.
• What is Vitamin A used for?


  Keeps the skin healthy

  Improves vison in the dark

  Strengthens the immune system
• What is Vitamin C used for?


  Growth and Repair
• What is Vitamin D used for?


  In the absorption of calcium
• What is calcium used for in the body?


  Strengthens bones and teeth
• What is iron used for in the body?


  Used in haemoglobin to transport oxygen in the blood
• What is water used for in the body?


  It helps to keep you from overheating

  Lubricates the joints and tissues

  Maintains healthy skin
• What is dietary fibre used for in the body?


  Keeps everything flowing through the digestive system
• Compare energy requirements of more and less active people


  The more active a person is, the greater the energy requirements
• Describe how energy requirements change as we age


  Adults require more energy than children
• What is the alimentary canal?


  The complete tube that food passes through as it passes through the body
• Function of the mouth


  To chew and break down food

  To produce digestive enzymes
• What is the oesophagus and its function?


  A tube which carries food from the mouth to the stomach
• What does the stomach do?


  A muscular sac containing acid which breaks does food into food molecules
• What role does the pancreas play in digestion?


  Produces digestive enzymes into the small intestines
• What are the 2 parts of the small intestine called?


  Duodenum and Ileum
• Function of the duodenum


  Receives food directly from the stomach and uses enzymes and chemical digestion to break the food down
• Function of the ileum


  Most nutrients are absorbed from the food in the ileum into the blood
• What is the function of the large intestine (colon)?


  Water is reabsorbed into the blood in the large intestine
• What is the function of the rectum?


  Stores faeces before egestion
• How does the peristalsis work to push food through the gut


  Muscles contract in a wave which pushes food along
• What enzymes break starch down to glucose?


  Maltase and amylase
• What group of enzymes break proteins down into amino acids?


  Proteases
• What group of enzymes break lipids down into glycerol and fatty acids?


  Lipases
• What does bile do?

  Neutralises the stomach acid and provides alkaline conditions for the digestive enzymes in the small intestine

  Also emulsifies fats
• Where is bile produced?


  The liver