Health, Disease & Development of Medicines GCSE EDEXCEL

• Health


  A state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity
• Being healthy is about more than just not being sick
• Even if someone is very physically fit, they still might be unhealthy if they have mental health issues or are socially isolated
• Communicable diseases


  Diseases that can be spread between individuals
• Non-communicable diseases


  Diseases that can't be transmitted between individuals, e.g. cancer and heart disease
• If you are affected by one disease, it could make you more susceptible to others as your body may become weakened
• Pathogens


  Organisms such as viruses, bacteria, fungi and protists that cause communicable diseases
• Cholera


  • Caused by the bacterium Vibrio cholerae
  • Symptoms: Diarrhoea
  • Spreads via contaminated water
• Tuberculosis


  • Caused by the bacterium Mycobacterium tuberculosis
  • Symptoms: Coughing and lung damage
  • Spreads through the air when infected individuals cough
• Malaria


  • Caused by a protist
  • Symptoms: Damage to red blood cells and liver
  • Spreads via mosquitoes acting as vectors
• Stomach ulcers


  • Caused by the bacterium Helicobacter pylori
  • Symptoms: Stomach pain
  • Spreads via oral transmission, e.g. swallowing contaminated water or food
• Ebola


  • Caused by the Ebola virus
  • Symptoms: Haemorrhagic fever (a fever with bleeding)
  • Spreads via bodily fluids
• Ash dieback


  • Caused by a fungus
  • Symptoms: Leaf loss and bark lesions
  • Spreads through the air by the wind and by moving infected ash trees between areas
• How to reduce/prevent transmission of Cholera

  ensuring access to clean water supplies
• How to reduce/prevent transmission of Tuberculosis

  infected should avoid crowded public places, practice good hygiene, sleep alone, keep house well ventilated
• How to reduce/prevent transmission of Malaria

  Use of mosquito nets and insect repellent
• How to reduce/prevent transmission of stomach ulcers

  Having clean water supplies and hygienic living conditions
• How to reduce/prevent transmission of Ebola

  By isolating infected individuals and sterilising possible areas of contamination
• How to reduce/prevent transmission of Chalara ash dieback

  Removing young, infected ash trees and replanting with a different species. Restricting the import/movement of ash trees
• Viruses


  Not cells, usually no more than a protein coat around a strand of genetic material
• Viruses


  • Have to infect living cells (called host cells) in order to reproduce
  • Specific types of viruses will only infect specific cells
• Life cycle of a virus


  1. Infect new host cell

  2. Reproduce by lytic pathway

  3. Can enter lysogenic pathway
• Lytic pathway


  1. Virus attaches to host cell and injects genetic material

  2. Virus uses host cell to replicate genetic material and produce new virus components

  3. Viral components assemble

  4. Host cell splits open, releasing new viruses
• Lysogenic pathway


  1. Injected genetic material incorporated into host cell genome

  2. Viral genetic material replicated with host DNA when host cell divides

  3. Viral genetic material eventually leaves genome and enters lytic pathway
• STIs


  Sexually Transmitted Infections, infections spread through sexual contact
• Chlamydia


  • Bacterium that behaves like a virus as it can only reproduce inside host cells
  • Can result in infertility in men and women
  • Spread can be reduced by wearing condoms, screening and treatment, or avoiding sexual contact
• HIV


  • Human Immunodeficiency Virus, kills white blood cells important for immune response
  • Infection leads to AIDS, when immune system deteriorates and fails
  • Spread via infected bodily fluids, can be prevented by using condoms, avoiding shared needles, and medication/treatment