Doc Brown's GCSE OCR Gateway Science-Biology Revision Notes

OCR GCSE Gateway Science Biology Module B1 Understanding Organisms

Unit-Item B1b Human health and diet

  1. Appreciate the fact that the populations of many countries are either underweight and starving or obese with associated health problems.

  2. Food is a source of energy and raw materials and you should consider the effects of diet on the body.

  3. Appreciate that countries having food emergencies raises ethical issues for science and technology.

  4. You may have compared the nutritional value of various breakfast cereals and considered the associated energy intake and further considered the energy content in various foods.

  5. Know how to carry out simple food tests on a variety of food types.

  6. Be able to explain why a balanced diet should include:

    • protein

    • carbohydrates and fats

    • minerals (limited to iron)

    • vitamins (limited to vitamin C)

    • fibre

    • water

  7. Demonstrate an understanding of how to calculate a personal estimated average daily requirement (EAR) for protein.

    • e.g. you may have recorded a day’s food intake and calculate the amount of protein.

  8. Demonstrate an understanding of how to calculate a Body Mass Index (BMI) and use provided information to make a decision as to what it indicates.

  9. Be able to interpret simple data on diet.

  10. Be able to explain why:

    • a high protein diet is necessary for teenagers

    • in many parts of the world diets are deficient in protein.

  11. Know that proteins are only used as an energy source when fats or carbohydrates are unavailable.

  12. Know that being very overweight (obese) is linked to increased health risks, to include arthritis, heart disease, diabetes and breast cancer.

  13. Know that:

    • carbohydrates are made up of simple sugars such as glucose

    • fats are made up of fatty acids and glycerol

    • proteins are made up of amino acids.

  14. Be able to explain how a balanced diet will vary depending on age, gender, activity, religion, personal choice (to include vegetarians and vegans) and medical issues (to include food allergies).

  15. HT only: Be able to describe the storage of biological molecules, to include:

    • carbohydrates are stored in the liver as glycogen or converted to fats

    • fats are stored under the skin and around organs as adipose tissue

    • BUT note that proteins are not stored.

  16. Be able to explain why protein deficiency (kwashiorkor) is common in developing countries e.g. due to:

    • overpopulation

    • limited investment in agricultural techniques.

  17. Be able to calculate the estimated average daily requirement (EAR) for protein using the formula:

    • EAR in g = 0.6 × body mass in kg

  18. Be able to calculate the Body Mass Index given the formula:

    • BMI = mass in kg/(height in m)2

    • and use it as a guide to understand the terms underweight, normal, overweight and obese.

  19. Be able to explain how low self-esteem, poor self-image and desire for perfection can lead to a poor diet and the increased risks involved.

  20. HT only: Be able to describe the differences between first and second class proteins:

    • proteins of animal origin are called first class proteins’ because they contain all the essential amino acids (these cannot be made by the body)

    • plant proteins are called ‘second class proteins’.

  21. HT only: You must understand that the EAR is an estimated daily figure for an average person of a certain body mass.

  22. HT only: You must be able to explain why the EAR for protein may vary depending on age, pregnancy and lactation.