Biology topic 3

• how do viruses spread?

  inserting genes into cells which causes them to produce more copies
• what is HIV?


  an STD/STI that causes AIDS - compromised immune system
• what is a pathogen?

  a micro-organism that causes disease: BACTERIA, VIRUSES, FUNGI, PROTISTS
• how does bacteria affect your body?

  it releases toxins into your body that damage cells,
• examples of bacteria:

  salmonella (undercooked food - food poisoning). gonorrhoea (STD, causes yellow discharge)
• what do FUNGIS do and what are protists?

  They damage cells, Protists are single-celled organisms e.g. malaria is caused by a protist that infects red blood cells
• what are rose black spot?

  it is a fungus that causes leaves to fall off
• what is Tobacco mosaic disease?

  discolour leaves, less chlorophyll -> stunts growth
• how does our bodies protect us from pathogen?

  skin stops, mucus in nose/trachea traps acid & enzymes kill pathogens.
• how do plants protect themselves from pathogens?

  cell wall, waxy cuticle & bark are barriers, antibacterial chemicals, poison & thorns to deter other organisms
• what are the two types of White blood cells?

  Lymphocytes & Phagocytes
• what does LYMPHOCYTES do?

  produce ANTITOXINS to neutralise toxins made by pathogens, and ANTIBODIES that bind to the ANTIGEN of a pathogen (only if they fit.) these stop viruses from infecting cells, causes them to clump together.
• what do PHAGOCYTES do?

  after the process of the LYMPHOCYTES, they will then ingest these pathogens.
• how does vaccines work?


  introduces a dead/inert version of a virus into ur body so you can gain immunity without you becoming ill.
• what do ANTIBIOTICS kill & don't kill?

  they kill BACTERIA, not viruses
• what are the two disadvantages of ANTIBIOICS.

  1. difficult to make them target specific bacteria. 2. more it is taken, the more bacteria becomes more resistant to them
• what drugs come from nature an how did they come about?


  Aspirin ( a painkiller) came from trees. Penicillin (the first antibiotic) came from a mould.
• what is a blind trial?

  test group is given drug, CONTROL group are give PLACEBO, without them being aware.
• how are synthetic drugs made?


  cost a lot to develop put through trials to access for EFFICACY (how well they work), TOXICITY and DOSE tested on CELL TISSUE, then ANIMALS, then HUMANS
• what is a double blind trial?

  when the PATIENTS and DOCTORS do not know which is which, this is to eliminate bias