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HUMAN NUTRITION
1
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Identify sources and describe functions of carbohydrate, protein, lipids, vitamins A,C and D,
and the mineral ions calcium and iron, water and dietary fibre as components of the diet
• Carbohydrate = pasta, bread etc
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used for body building
• Lipids = butter, eggs etc
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protects surface of eye and connective tissue
• Vitamin C = fresh fruit and vegetables
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Helps bones absorb calcium and phosphorus
• Calcium = dairy, fish = makes bones and teeth
• Iron = red meat, liver etc
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Breaks large molecules by hydrolysis
• Fibre = bulks out food so helps gut muscles
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Understand that energy requirements vary with activity levels, age and pregnancy
• Active people require more energy
• Pregnant people require more energy
• Energy requirements decrease with age after full adulthood has been reached
4
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Mouth = food enters canal, digestion begins
ii
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Stomach = muscular organ where digestion continues, (stomach acid)
iv
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Large intestine = (COLON) water reabsorbed, (RECTUM) faeces stored,
(ANUS) faeces leave alimentary canal
vi
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Understand the process of ingestion, digestion, absorption, assimilation and egestion
• Ingestion = the process of taking food or drink into the body by swallowing or
absorbing it
• Digestion = the physical breakdown of large pieces of food into smaller pieces which
can then be accessed by digestive enzymes
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Then used for
energy and to build up into chemicals needed by the cells
Egestion = undigested food with water, dead cells, any leftovers etc moves through
large intestine
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Becomes faeces
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Explain how and why food is moved through the gut by peristalsis
• Waves of muscle contraction that moves food through the gut
7
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Stomach and small intestine
• Lipases = fats into fatty acids and glycerol
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Mouth and small intestine
• Maltase = maltose into glucose
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Understand that bile is produced by the liver and stored in the gall bladder, and understand
the role of bile in neutralising stomach acid and emulsifying lipids
• Produced in liver
• Stored in gall bladder
• Released into small intestine when needed
• Bile is alkaline
• It neutralises the stomach acid which would be too acidic for digestive enzymes to
work
• It emulsifies fats by breaking the fat into tiny droplets
• This increases the surface area and provides a larger surface for lipase
• This means quicker digestion
9
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Describe an experiment to investigate the energy content in a food sample
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Energy transferred = mass of water (g) x 4
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Temperature increase
ii

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