Biology: Keeping Healthy

Topics: Bacteria, Gene, DNA Pages: 29 (5907 words) Published: July 2, 2013
GCSE Biology for teaching from September 2011 onwards (version 1.1)

3.3 Unit 1: Biology 1
B1.1 Keeping healthy

Subject Content

A combination of a balanced diet and regular exercise is needed to help keep the body healthy. Our bodies provide an excellent environment for many microbes which can make us ill once they are inside us. Our bodies need to stop most microbes getting in and deal with any microbes which do get in. Vaccination can be used to prevent infection. Candidates should use their skills, knowledge and understanding to: ■ evaluate information about the effect of food on health Additional guidance: Candidates will be given data to work from.

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evaluate information about the effect of lifestyle on development of disease analyse and evaluate claims made by slimming programmes, and slimming products.



B1.1.1 Diet and exercise
Additional guidance:

a) A healthy diet contains the right balance of the different foods you need and the right amount of energy. Carbohydrates, fats and proteins are used by the body to release energy and to build cells. Mineral ions and vitamins are needed in small amounts for healthy functioning of the body. A person is malnourished if their diet is not balanced. This may lead to a person being overweight or underweight. An unbalanced diet may also lead to deficiency diseases or conditions such as Type 2 diabetes. b) A person loses mass when the energy content of the food taken in is less than the amount of energy expended by the body. Exercise increases the amount of energy expended by the body. c) The rate at which all the chemical reactions in the cells of the body are carried out (the metabolic rate) varies with the amount of activity you do and the proportion of muscle to fat in your body. Metabolic rate may be affected by inherited factors. d) Inherited factors also affect our health; for example cholesterol level.

Knowledge and understanding of the specific functions of nutrients and the effects of any deficiency in the diet is not required.

Additional guidance:

e) People who exercise regularly are usually healthier than people who take little exercise.

The effect of exercise on breathing and heart rate is not required.

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GCSE Biology for teaching from September 2011 onwards (version 1.1)

B1.1.2 How our bodies defend themselves against infectious diseases Candidates should use their skills, knowledge and understanding to: ■ relate the contribution of Semmelweis in controlling infection to solving modern problems with the spread of infection in hospitals ■

Additional guidance: Candidates will be given data to work from.

Subject Content

explain how the treatment of disease has changed as a result of increased understanding of the action of antibiotics and immunity evaluate the consequences of mutations of bacteria and viruses in relation to epidemics and pandemics evaluate the advantages and disadvantages of being vaccinated against a particular disease.





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a) Microorganisms that cause infectious disease are called pathogens. Additional guidance:

b) Bacteria and viruses may reproduce rapidly inside the body and may produce poisons (toxins) that make us feel ill. Viruses damage the cells in which they reproduce. c) The body has different ways of protecting itself against pathogens. d) White blood cells help to defend against pathogens by: ■ ■

Knowledge of the structure of bacteria and viruses is not required.

ingesting pathogens producing antibodies, which destroy particular bacteria or viruses producing antitoxins, which counteract the toxins released by the pathogens.



e) The immune system of the body produces specific antibodies to kill a particular pathogen. This leads to immunity from that pathogen. In some cases, dead or inactivated pathogens stimulate antibody production. If a large proportion of the population is immune to a pathogen, the spread of the pathogen is very much reduced. f)...
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