Biology Revision B1.1


B1.1- Keeping Healthy

Healthy Diets:

  • to maintain a healthy diet, you need to eat the correct balance of carbohydrates, fats, proteins, fibre, vitamins, minerals, water and energy
  • carbohydrates, proteins and fats allow the body to release energy and build cells
  • minerals and vitamins are needed in small amounts for a healthy functioning body
  • if their diet is not balanced, a person may become malnourished, and this can lead to
  • them becoming underweight or overweight
  • deficiency diseases, eg. scurvy or type 2 diabetes


  • exercise increases the amount of energy expended by the body
  • mass is lost if the energy expended through exercise is more than the energy consumed

Metabolic Rate:

  • the metabolic rate is the rate at which all the chemical reactions in the cells of the body are carried out
  • this varies with the amount of exercise you do, and the proportion of fat to muscle
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B1.1- Keeping Healthy

Bacteria and Viruses:

  • microorganisms that cause infectious diseases are called pathogens
  • there are two types of pathogens
  • bacteria, which are very small, reproduce very quickly, can produce toxins that make us ill, and cause tetanus, cholera an tuberculosis
  • viruses, which are even smaller, reproduce very quickly once inside living cells ( which are then damaged ), can produce toxins that make us I'll, and cause colds, flu and measles

Defence against Pathogens:

  • white blood cells form part of the body's immune system, and fight infection by
  • ingesting pathogens
  • producing antitoxins
  • producing antibodies

Treatment of Disease:

  • although painkillers are useful, they don't kill pathogens
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B1.1- Keeping Healthy


  • antibiotics ( such as penicillin ) are often used to kill bacteria inside the body
  • specific antibiotics = specific bacteria
  • cannot kill viruses
  • difficult to develop drugs that destroy viruses without damaging the body's tissues

Overuse of Antibiotics:

  • overuse can lead to resistance
  • resistance happens when bacteria mutate to produce a new resistant strain


  • a person can squire immunity through vaccination, this is the process
  • inactive/ dead pathogen infected into body
  • white blood cells produce antibodies to destroy pathogen
  • immune
  • used for measles, mumps, rubella etc.
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B1.1- Keeping Healthy

Preparing a Culture Medium

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ocr 21st century?

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