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In this unit, students will know that humans need carbohydrates and fats for energy and proteins for energy, building new cells, making enzymes and defense against diseases. Students will also know good dietary sources of carbohydrates, fats, proteins, Vitamin C and D, iron and calcium and the health problems that will occur from an imbalanced diet. Experiments to investigate the nutrient contents in food will be done using tests like Benedict’s test, Biuret test and iodine test. Students will move on to understand that the alimentary canal is a tube passing through the body and that nutrients cannot be used by cells until they have passed through the walls of the alimentary canal by absorption in the small intestine. Labeling the appropriate parts of the digestive system are also essential – mouth, esophagus, stomach, small intestine, colon, rectum, anus and liver. Names and functions of enzymes like amylase, protease and lipase is essential. The process of digestion in the mouth, stomach and small intestine to the absorption of digested food by the small intestine and absorption of water in the large intestine needs to be accurately described.

Learning Targets

  • Define nutrition as taking in of nutrients which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating them


List the chemical elements that make up:

  • carbohydrates
  • fats
  • proteins

Describe the synthesis of large molecules from smaller basic units, i.e.

  • simple sugars to starch and glycogen
  • amino acids to proteins
  • fatty acids and glycerol to fats and oils

Describe tests for:

  • starch (iodine solution)
  • reducing sugars (Benedict’s solution)
  • protein (biuret test)
  • fats (ethanol)

List the principal sources of, and describe the importance of:

  • carbohydrates
  • fats
  • proteins
  • vitamins (C and D only)
  • mineral salts (calcium and iron only)
  • fibre (roughage)
  • water

Describe the deficiency symptoms for:

  • vitamins (C and D only)
  • mineral salts (calcium and iron only)

Plant nutrition

  • Define photosynthesis as the fundamental process by which plants manufacture carbohydrates from raw materials using
    energy from light.
    Explain that chlorophyll traps light energy and converts it into chemical energy for the formation of carbohydrates and their subsequent storage.
    State the word equation for the production of simple sugars and oxygen.
    State the balanced equation for photosynthesis in symbols 6CO2 + 6H2O light C6H12O6 + 6O2
    Investigate the necessity for chlorophyll, light and carbon dioxide for photosynthesis, using appropriate controls.
    Investigate and state the effect of varying light intensity on the rate of photosynthesis (e.g. in submerged aquatic
    Describe the intake of carbon dioxide and water by plants.
    Identify and label the cuticle, cellular and tissue structure of a dicotyledonous leaf, as seen in cross-section under the light

Animal nutrition


Discuss the concept of a balanced learner in terms of making sure to have a good diet and regular lifestyle in spite of a busy school schedule.


  • State what is meant by the term balanced diet and describe a balanced diet related to age, sex and activity of an individual
  • Describe the effects of malnutrition in relation to starvation, coronary heart disease, constipation and obesity

Food supply


This section is an opportunity to approach the topic of food security in terms of availability, safety, and quality.

Discuss ways in which the use of modern technology has resulted in increased food production (to include modern agricultural machinery, chemical fertilizers, pesticides and herbicides, artificial selection)

Human alimentary canal 

  • Define ingestion as taking substances (e.g. food, drink) into the body through the mouth
  • Define egestion as passing out of food that has not been digested, as faeces, through the anus
  • Identify the main regions of the alimentary canal and associated organs including mouth, salivary glands, oesophagus, stomach, small intestine: duodenum and ileum, pancreas, liver, gall bladder, large intestine: colon and rectum, anus
  • Describe the functions of the regions of the alimentary canal listed above, in relation to ingestion, digestion, absorption, assimilation and egestion of food

Mechanical and physical digestion

  • Define digestion as the break-down of large, insoluble food molecules into small, watersoluble molecules using mechanical and chemical processes
  • Identify the types of human teeth and describe their structure and functions
  • State the causes of dental decay and describe the proper care of teeth
  • Describe the process of chewing
  • Describe the role of longitudinal and circular muscles in peristalsis
  • Outline the role of bile in emulsifying fats, to increase the surface area for the action of enzymes
  • Describe how fluoride reduces tooth decay and explain arguments for and against the addition of fluoride to public water supplies

Chemical digestion

  • State the significance of chemical digestion in the alimentary canal in producing small, soluble molecules that can be absorbed
  • State where, in the alimentary canal, amylase, protease and lipase enzymes are secreted
  • State the functions of a typical amylase, a protease and a lipase, listing the substrate and end-products


  • Define absorption as movement of digested food molecules through the wall of the intestine into the blood or lymph
  • Identify the small intestine as the region for the absorption of digested food
  • Describe the significance of villi in increasing the internal surface area of the small intestine
  • Describe the structure of a villus, including the role of capillaries and lacteals
  • State the role of the hepatic portal vein in the transport of absorbed food to the liver
  • Identify the role of the small intestine and colon in absorption of water (the small intestine absorbs 5–10 dm3 per day, the colon 0.3–0.5 dm3 per day)


  • Define assimilation as movement of digested food molecules into the cells of the body where they are used, becoming part of the cells
  • Describe the role of the liver in the metabolism of glucose (glucose ? glycogen) and amino acids (amino acids ? proteins and destruction of excess amino acids)
  • Describe the role of fat as an energy storage substance
  • State that the liver is the site of breakdown of alcohol and other toxins

Presentation media

Labs and activities

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