B2

GCSE Science B2 - biology topic

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  • Created by: Beatrice
  • Created on: 08-06-12 17:17

Keeping Healthy

keeping healthy involve:

  • balanced diet
  • exercise
  • sensible weight
  • cleanliness (fungi,bacteria,virus)

Defence against disease - symptons form infectous diseases are caused by microorganisms damaging our cells or by the toxins they produce (e.g.skin,stomach acid, finger nails, hair, ear wax, musus, eyelashes, blod clotts)

Bacterial growth = ASEXUAL REPRODUCTION

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IMMUNE SYSTEM

  • The human body has barriers to sop harmfl MO's getting insde
  • Chemicals in tears destroy microrganisms 
  • If microorganisms get in through your outh, acid in the stomach destroys most of them
  • The skin is a physical barrier to mircoorganisms 
  • White blood cells surrond the bacteria and digest them
  • The parts of your body that fight infections are called your immune system - white blood cells are an important part of your immune system
  • 1. Your skin is covered with bacteria others live in your mouth, gut and reproductive passages
  • 2. Some even prevent infections - the 'good' bacteria, they protect you from the invasion of other microorganisms which may be harmful
  • 3. The antibodies kill off both 'good' and harmful bacteria but not the fungus
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VACCINES

A vaccination releases dead/inactive microorganisms of a particular disease this is prepare antibodis for that disease incase its caught again

People can have some side effects to vaccinations however usually vaccinations work without any problems

Some vaccinations such as the flu jab, you have to have it annually this is because the bacteria changes

Vaccines:

  • no vaccines ar riskfree
  • different people react differently to vaccines
  • this is due to genetic differences

antimicrobials:

  • these are chemicals that inhibit or kill bacteria viruses and fungi
  • antibiotics are a type of antimcrobials that are effective against bacteria but not viruses

resistance:

  • over a period of time and fungi may become reistant to antimicrobias
  • this can b due to mutations in the genes that lead to variaties that are less affected by the antimicrobias
  • to reduce this effectwe should only use atibiotics when necessary and always compete the course
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TESTING DRUGS

  • Indentificaton - find an effective chemical
  • Manufacture - mae the drug
  • Testing - wheather it works 
  • Trials - review how well it works 
  • Rlease - quality conrol

Trials:

TEST ON HUMAN CELLS

  •  check ifferent concentrations
  • test different body cells
  • in  vitro testing (IVF)

TES ON ANIMALS

  • checking that the drug does the same to an organism as it does to a colection of cells

CLINICAL TRIALS

  • if the drug passes the animal trials. clncal trials can begin
  • this produces data on safety on effectiveness of the drug
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CIRCULATION

oxygen - getting 02 from lungs to cells

deoxygenated blood from the liver, kidneys,legs,head & arms travel to the heart & lungs

oxygenated blood from lungs to the heart and then to head,arms,liver,digestive system, kidneys & legs

Artery:

  • outside - thick layer of muscle and elastic fibres
  • Inside - thick outer layer

Vein:

  • outside - thin outer wall
  • inside - thin layer of muscle and elastic fibres 
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