INFECTION + RESPONSE

• what are pathogens?

  microorganisms that cause infectious disease
• how can pathogens be spread?


  - direct contact

  - water

  - air
• how big is bacteria?

  1/100th the size of body cells
• how do bacteria make us feel ill?


  they produce toxins that damage tissues
• how big is a virus?

  1/100th the size of bacteria
• how do viruses cause cell damage?


  they live and reproduce inside cells until the host cell explodes
• what are protists?


  single celled eukaryotes
• what is measles?

  a viral disease which can be fatal if complications arise
• what are the symptoms of measles?

  - fever

  - red skin rash
• how is measles spread?


  the inhalation of droplets from sneezes and coughs
• what is HIV?


  human immunodeficiency virus
• what are the initial symptoms of HIV?

  flu-like illness
• what is late stage HIV what happens during it?


  AIDS; when the body's immune system becomes so badly damaged it can no longer deal with other infections or cancers
• how is HIV spread?

  - sexual contact

  - exchange of body fluids
• what is tobacco mosaic virus (TMV)?


  a widespread plant pathogen
• what are the symptoms of TMV?

  a distinctive mosaic pattern of discoloration which affects the growth of the plant due to lack of photosynthesis
• what is salmonella?


  a bacterial disease that causes food poisoning
• how is salmonella spread?


  - bacteria ingested in food (poultry)

  - food prepared in unhygienic conditions
• what are the symptoms of salmonella?

  - fever

  - stomach cramps

  - vomiting

  - diarrhoea
• what is gonorrhea?


  a sexually transmitted bacterial disease
• what are the symptoms of gonorrhea?


  - thick yellow or green discharge

  - pain when urinating
• how is gonorrhea treated?

  antibiotics until many resistant strains appeared
• how is gonorrhea spread?


  by sexual contact
• how is the spread of gonorrhea controlled?

  - treatment with antibiotics

  - barrier method of contraception
• what is rose black spot?


  a fungal plant disease
• what are the symptoms of rose black spot?

  - purple or black spots on leaves which turn yellow and drop early

  - stunted growth
• how is rose black spot spread?


  water or wind
• how can rose black spot be treated?

  - fungicides

  - removing and destroying the affected leaves
• what are antibiotics?

  medicines that help to cure bacterial disease by killing infective bacteria inside the body
• where does the heart drug digitalis originate from?


  foxgloves
• where does the painkiller aspirin originate from?


  willow
• who discovered penicillin?

  alexander fleming from penicillium mold
• what are new drugs extensively tested for?

  - toxicity

  - efficacy

  - dose
• what are the stages of a drug trial?

  - preclinical: using cells, tissues and live animals

  - clinical: very low doses given at the start

  - if the drug is safe, optimum dosage is found
• what is a double blind trial?


  when neither the doctor nor the patients know who has the drug or the placebo
• what are monoclonal antibodies produced from?


  a single clone of cells
• how are monoclonal antibodies produced?


  - by stimulating mouse lymphocytes to make a particular antibody

  - the lymphocytes are combined with tumor cells to make a hybridoma cell

  - single hybridoma cells are cloned to produce many identicall cells that all produce the same antibody

  - collected and purified
• how are monoclonal antibodies used in pregnancy tests?


  - the end of the stick has antibodies with blue beads that bind to HCG, found in pregnant women's urine

  - the test strip has more antibodies attached to the paper

  - if a woman is pregnant and pees on the strip, HCG binds to the antibodies with the blue beads, travels up the stick and bind to the antibodies on the test strip

  - so the blue beads get stuck to the strip, turning it blue
• how are monoclonal antibodies used to treat cancer?


  - cancer cells have antigens that normal cells don't (called tumor markers)

  - monoclonal antibodies can be paired with an anti-cancer drug and bind to those antigens, killing the cancer cell
• how are monoclonal antibodies used in labs and research?

  - used to bind to hormones and other chemicals in blood to measure their levels

  - test blood samples for pathogens

  - locate specific molecules on a cell or tissue