Topic 5- disease

• Pathogens are organisms that cause disease.
• The presence of one disease leads to high susceptibility to other diseases.
• Non-communicable diseases are non-infectious and non-transmissible.
• Communicable diseases are infectious and transmissible.
• The 4 major categories of non-communicable diseases:

  • Cardiovascular diseases.
  • Diabetes.
  • Chronic Respiratory Diseases.
  • Cancer.
• The bacterias - cholera, tuberculosis.
• The viruses - HIV, ebola, influenza.
• Lytic cycle:

  1. The phage infects a cell.
  2. The phage DNA circularises, remaining separate from the host DNA.
  3. Phage DNA replicates and phage proteins are made. New phage particles are assembled.
  4. The cell lyses, releasing phage.
• Lysogenic cycle:

  1. The phage infects a cell.
  2. The phage DNA becomes incorporated into the host genome.
  3. The cell divides, and prophage DNA is passed onto daughter cells.
  4. Under stressful conditions, the phage DNA is excised from the bacterial chromosome and enters the lytic cycle.
• The most effective way of preventing sexually transmitted bacterial diseases is using a condom.
• The most common methods of HIV transmission:

  • Unprotected sex with someone who's infected.
  • Sharing needles with someone who's infected.
• Plants have physical barriers to defend themselves against pests and pathogens (waxy leaf cuticle, tough cell walls, leaf hairs, barbs, thorns).
• Physical barriers - skin, mucus, cilia.
• Chemical barriers - hydrochloric acid in stomach and lysozymes in tears, saliva, human milk, mucus.
• Stages of developing medicine:

  • Discovery.
  • Development.
  • Pre-clinical and clinical testing.
• Antibiotics - inhibit cell processes in the bacterium but not the host organism.
• Important that petri dishes and vials are kept shut to prevent the escape of potentially dangerous micro-organisms.
• Autoclaves - using high pressure and temperature to sterilise petri dishes.
• Inoculating loops are placed in a flame slowly from base to tip to sterilise them to transfer micro-organisms to petri dishes or vials.
• BMI = mass/height squared.
• Causes of Cardiovascular disease:

  • Smoking.
  • High cholesterol.
  • High blood pressure.
  • Diabetes.
• Monoclonal antibodies are attached to the end of a pregnancy test stick onto which a woman urinates.
• A rat is injected with the antigen, HCG in the spleen. Spleen cells are collected alongside myeloma cells in cell culture myeloma line, and selected to grow only hybrid cells. Then, separate hybrid cells and allow them to proliferate into clones (hybridomas). After that, screen for desired antibody (HCG). This creates antibodies. The chosen hybridome is grown to produce large batches of desired monoclonal antibodies.