Keeping Healthy - Biology topic 1

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  • Created by: Emma
  • Created on: 25-10-12 18:29


What is a drug?

A drug is a chemical that changes the CHEMICAL processes in people's bodies and changes the way the body works.

People can become dependent on or addicted to the drug and can suffer withdrawal symptoms without them.

Types of drugs:

  • Illegal - eg, cocaine, heroine, etc
  • Legal - eg, paracetamol, nurofen, etc
  • Prescription - Antibiotics - You HAVE to take them because your GP advised you to
  • Non-prescription - Paracetemol
  • Recreational - Taken for pleasure
  • Hard - Have a negative impact
  • Stimulant - Drugs that stimulate the mind eg. Caffeine
  • Legal but prohibited - Athletes arent allowed medicines which give them energy by other are allow. eg. Steroids
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  • Medical - For medical use only
  • Non-medical - Not for medical use
  • Depressant - Slows you down/reactions eg. Alcohol


  • Developed and tested as a sleeping pill
  • Also used for morning sickness - was not tested
  • Many babies born to these women had severe limb abnormalities
  • Thalidomide was banned and drug testing was made more rigorous
  • Thalidomide is now used to treat leprosy in NON PREGNANT women

Toxicity - How poisonous/dangerous the drug is

Efficacy - How well it works

Dose - How much you can take

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How new drugs are tested:

  • Rigorously, because of what happened with the Thalidomide
  • For toxicity, efficacy and dose
  • Using cells, tissues and animals as models to predict how the drugs may behave on humans
  • In Clinical Trials

Drug testing:

  • First tested on animals or cells to see if they are poisonous
  • Then on humans in clinical trials
  • Trialed in low doses to see any side effects
  • Further trials to identify dose
  • Some patients are given a placebo

Statins - Lower blood cholestrol to reduce the risk of Coronary Heart Disease

Coronary Heart Disease - Build up of cholestrol in arteries, can cause heart disease. Oxygen and glucose can not get to heart muscle

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Drugs and Athletics:

  • Some people might take a steroid to make them stronger
  • Some people might take a stimulant to make their heart pump faster/to respire quicker

They are BOTH legal but prohibited


Balanced diet:

  • Carbohydrate - release energy in respiration
  • Protein - growth and repair
  • Fibre - prevents constipation
  • Vitamins and Minerals - to keep us healthy
  • Water - to keep hydrated
  • Fat - energy store
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Keeping Healthy


  • Not having a balanced diet
  • Over/Under nutrition
  • Deficiency diseases
    • vitamins
    • minerals

Metabolism - Rate at which chemical reactions in the body are carried out

Metabolism (caused by):

  • Excersise
  • Iherited/genetic
  • proportion of muscle:fat


  • Doctor in the mid 1800's
  • He realised why women die of 'childbed fever'
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Keeping Healthy

  • He noticed doctors carrying out work on dead bodies then not washing their hands and delivering babies
  • He got doctors to wash their hands before delivering babies - less women died
  • He concluded that something was being carried from the dead bodies to the women
  • In the end he had a mental breakdown as no-one believed him
    • How can they believe they were passing on something they couldnt see?
    • They didnt want to be blamed for all the deaths

MRSA - resistant to some antibiotics

Ways pathogens enter the body + Barrier mechanism which prevents the disease:

Droplet infection - Mucus & cilia

Contaminated food - Stomach acid

Contact - Skin

Via Cuts - Blood clots

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How white blood cells destroy bacteria:

  • White blood cells are attracted to infected area
  • The white blood cell engulfs the bacterium which ends up in its cytoplasm
  • Enzymes from the cell digest the bacterium and the soluble products are absorbed

For each different antigen you need a specific antibody that matches it so it can destroy it

Vaccine - Dead/weakened pathogen (antigens are essential)

How antibiotic resistance evolves (eg MRSA):

  • Apply antibiotics and all bacteria dies except from one mutated bacteria
  • The mutated bacteria multiplies and is resistant to the antibiotic which kills the other bacteria
  • Mutation happens again. The new bacteria is resistant to the new antibiotics and the ones before
  • And so on...
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Keeping Healthy

Mutation - change in DNA

Viruses hide inside your cells. So to kill the virus, the antibiotic would have to kill your cells first.

Advantages to being vaccinated:

  • Immune to the disease
  • Hard immunity

Disadvantages to being vaccinated:

  • Possible side effects
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