Infection and response

• Vector


  an organism that carries a pathogen but does not suffer from the disease
• Toxin


  a poisonous chemical, produced by certain pathogens
• Non-specific defences


  the first line of defence against pathogens in general; includes skin, hair, mucus, etc.
• Immune system


  the body's defence system against infections and diseases (consists of white blood cells and antibodies)
• Phagocytosis


  1. track down a pathogen, and then bind to it.

  2. the phagocyte's membrane will then surround the pathogen and engulf it.

  3. enzymes inside the phagocyte break down the pathogen in order to destroy it
• Antibody


  a protein produced in the body by the immune system to kill specific pathogens
• Antigen


  a marker molecule found on the surface of microorganisms
• Antitoxin


  a chemical released from white blood cells that can neutralise harmful toxins
• Immunity


  the ability to attack a pathogen before it causes disease due to a previous encounter with the pathogen
• Vaccination


  a liquid preparation containing inactive or dead pathogens, used to make the body produce antibodies to provide protection against disease
• MRSA


  (Methicillin-Resistant Staphylococcus Aureus) - an antibiotic-resistant bacterium; a 'superbug
• Digitalis


  a drug extracted from foxgloves, used to treat heart problems
• Aspirin


  a painkilling drug first extracted from the bark of willow trees
• Penicillin


  an antibiotic extracted from the Penicillium fungus
• Double-blind trial


  neither the doctors or patient know if they are receiving a placebo or the actual drug
• Placebo


  a fake drug used in the testing of medication
• Monoclonal antibody


  an antibody produced by a single clone of cells
• Hybridoma


  a cell produced by the joining of a tumour cell and a white blood cell
• HCG


  a hormone found in urine during early pregnancy
• Tobacco-mosaic virus(TMV)


  a virus that attacks tobacco and related plants, causing discoloured patches on the leaves
• Aphid


  a small insect, often called 'greenfly', that sucks food out of the phloem of plants
• Deficiency disease


  a disease caused by the lack of an essential element in the diet
• Mimicry


  when one organism evolves to look or behave like an organism of another species as a defence mechanism
• Agar gel


  Widely used solid (gel) culture medium used for growing microorganisms
• Aphids


  Insects that penetrate the plant phloem and feed on the dissolved food. They act as plant pathogens and are also vectors that carry pathogenic viruses, bacteria, and fungi into healthy plant tissue
• Binary fission


  Reproduction by simple cell division, for example in bacteria
• Chlorosis


  The yellowing seen on the leaves of plants when they cannot make chlorophyll due to a lack of magnesium ions
• Communicable disease


  Caused by pathogens which can be passed on between organisms
• Culture Medium


  A liquid or gel used to support the growth of microorganisms or other cultures, often containing specific nutrients
• Inoculate


  Introducing microorganisms to a culture medium, or introducing modified microorganisms into an individual to protect them against disease
• Microorganism


  Any organism of microscopic or submicroscopic size.
• Mutation


  A change in the genetic material of an organism
• Non-communicable disease


  Caused by pathogens which cannot be passed on and are not infectious
• Pathogen


  Microorganisms such as bacteria and viruses that cause disease
• Sexually Transmitted Infection (STI)


  An infection that is transmitted via body fluids through sexual contact
• Vaccine


  Dead or inactive pathogenic material used in vaccination to develop immunity to a disease in a healthy person
• Virus


  Pathogens that are much smaller than bacteria and can only reproduce inside living cells of other organisms
• 4 types of pathogens

  Viruses, Bacteria, Fungi, Protists
• Health


  The state of physical and mental well-being, not just the absence of disease
• Disease


  The condition in which the body is not working correctly