DP Biology (last assessment 2024)
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D.1 Human nutrition

Description

Nature of science:
Falsification of theories with one theory being superseded by another—scurvy was thought to be specific to humans, because attempts to induce the symptoms in laboratory rats and mice were entirely unsuccessful. (1.9)
Understandings:
  • Essential nutrients cannot be synthesized by the body, therefore they have to be included in the diet.
  • Dietary minerals are essential chemical elements.
  • Vitamins are chemically diverse carbon compounds that cannot be synthesized by the body.
  • Some fatty acids and some amino acids are essential.
  • Lack of essential amino acids affects the production of proteins.
  • Malnutrition may be caused by a deficiency, imbalance or excess of nutrients in the diet.
  • Appetite is controlled by a centre in the hypothalamus.
  • Overweight individuals are more likely to suffer hypertension and type II diabetes.
  • Starvation can lead to breakdown of body tissue.
Applications and skills:
  • Application: Production of ascorbic acid by some mammals, but not others that need a dietary supply.
  • Application: Cause and treatment of phenylketonuria (PKU).
  • Application: Lack of Vitamin D or calcium can affect bone mineralization and cause rickets or osteomalacia.
  • Application: Breakdown of heart muscle due to anorexia.
  • Application: Cholesterol in blood as an indicator of the risk of coronary heart disease.
  • Skill: Determination of the energy content of food by combustion.
  • Skill: Use of databases of nutritional content of foods and software to calculate intakes of essential nutrients from a daily diet.
 International-mindedness:
  • The Vitamin and Mineral Nutrition Information System (VMNIS), formerly known as the Micronutrient Deficiency Information System (MDIS), was established in 1991 following a request by the World Health Assembly to strengthen surveillance of micronutrient deficiencies at the global level.
Theory of knowledge:
  • There are positive effects of exposure to sun such as the production of Vitamin D as well as health risks associated with exposure to UV rays. How can conflicting knowledge claims be balanced?
Utilization:
Syllabus and cross-curricular links:
Biology
Topic 6.1 Digestion and absorption
Geography
Part 2F The geography of food and health
Chemistry
Topic B5 Vitamins

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