Biology

• What is a pathogen?


  Micro-organism that causes infectious disease; virus, bacteria, and fungi.
• How do bacteria cause disease?


  By damaging host cells, producing toxins, and taking nutrients.
• What is the mechanism by which viruses cause disease?


  By injecting genetic material into host cells, making them produce more virus particles.
• What is a vaccine?


  Injection containing weakened or inactive pathogens to build immunity.
• What is the function of antibiotics?


  Drugs that block specific types of bacteria.
• What is a parasite?


  Lives in or on the host and takes nutrients from it.
• Why are prokaryotes significant in the context of bacteria?


  A bacterium is a prokaryote and is not affected by certain treatments.
• What is a vector in the context of disease transmission?


  An organism that carries something to a different host.
• What is antiserum?


  Injected prepared antibodies (serum).
• What is an antigen?


  Foreign body; substance in a pathogen recognized by the body.
• What is a lymphocyte?


  White blood cell that makes antibodies.
• What is the role of antibodies?


  Proteins produced by plasma cells, specific to one antigen.
• What are phagocytic white blood cells?


  White blood cells that engulf a pathogen during phagocytosis.
• What is the origin of digitalis?


  Heart drug originally from foxglove flowers.
• What is aspirin used for?


  Pain-killing drug originally from willow.
• Who discovered penicillin?

  Alexander Fleming.
• What are the symptoms of measles?


  Spots, breathlessness, and high fever.
• How is measles transmitted?


  Spread through airborne droplets from infected people.
• What are the symptoms of whooping cough?


  Uncontrollable bouts of coughing, especially in children.
• How is whooping cough transmitted?


  Spreads via airborne droplets; highly contagious.
• What is HIV and how does it affect the body?


  Attacks the human immune system and is difficult to treat.
• How is HIV transmitted?


  Spread by sexual contact, through body fluids.
• What are the symptoms of malaria?


  Usually unnoticed but can be serious and often fatal.
• How is malaria transmitted?


  Spread through bites from mosquitoes.
• How can polio be prevented?


  A vaccine now prevents polio.
• What are the symptoms of tuberculosis?


  Often begins in the lungs and spreads from there.
• How is tuberculosis transmitted?


  Spread through droplets of sputum.
• What are the symptoms of influenza?


  Flu-like symptoms and high fever.
• How is influenza transmitted?


  Spread through airborne droplets, often carried on surfaces.
• What are the symptoms of cholera?


  Diarrhoea and vomiting.
• How is cholera transmitted?


  Spread through contaminated water and food.
• What is pneumonia?


  Inflammation of the alveoli that can be fatal.
• How is pneumonia treated?


  Treated by using antibiotics.
• What are the stages of drug testing?


  1. Testing in a laboratory using cells, tissues, and live animals.
  2. Testing healthy and sick animals and patients.
  3. Evaluating drug effectiveness.
  4. Assessing drug tolerance.
  5. Checking for harmful effects.
  6. Confirming the drug can cure illness.
  7. Double-blind trials for unbiased results.
• What are the components of the human defense system?

  • Skin
  • Eyes
  • Trachea and bronchi
  • Stomach
• What are the stages of vaccination?

  1. Dead or weakened pathogens are injected.
  2. Stimulates white blood cells to make specific antibodies.
  3. White blood cells remember how to produce the correct antibody.
  4. Quick response upon re-exposure to the pathogen.
• What are the steps in clinical trials?


  1. Start with very low doses of the drug.
  2. If safe, find the optimum dose.
  3. Conduct double-blind trials with placebos.
• What are the symptoms of plant diseases?


  • Stunted growth
  • Spots on leaves
  • Areas of decay (rot)
  • Growths
  • Malformed stems or leaves
  • Discolouration
  • Presence of pests (e.g., aphids)
• What are the sources of information for diagnosing plant diseases?

  • Gardening manuals or websites
  • Laboratory testing of infected plants
  • Testing kits with monoclonal antibodies
• What are the effects of ion deficiencies in plants?

  • Nitrate deficiency: stunted growth due to lack of protein synthesis.
  • Magnesium deficiency: chlorosis due to lack of chlorophyll.