infection + response

• what is a communicable disease?

  an infectious disease
• what is are the characteristics of viruses?

  very small

  move into cells and replicate

  damage and kill cells
• what are characteristics of bacteria?

  small

  multiply quickly through binary fission

  produce toxins that damage cells
• what are ways that diseases spread?

  direct contact

  by water

  by air
• how can we reduce the spread of pathogens?

  improving hygiene

  reducing contact with infected individuals

  vaccinations
• what are three viruses?

  measles

  HIV

  tobacco mosaic virus (plants)
• what are the characteristics of measles?

  symptoms = fever, red skin and rash

  spread = through air droplets

  prevented = vaccines
• what are the characteristics of HIV?

  symptoms = flu like symptoms

  spread = sexual contact or exchange bodily fluids

  prevented = condoms
• what are the characteristics of tobacco mosaic virus?

  symptoms = discolouration of leaves

  spread = contact between diseased plants

  prevented = good field hygiene
• what are two bacterial diseases?

  salmonella

  gonorrhoea
• what are the characteristics of salmonella?

  symptoms = fever, stomach cramps and vomiting

  spread = raw meat and eggs

  prevented = cooking food
• what are the characteristics of gonorrhoea?

  symptoms = thick yellow or green discharge

  spread = unprotected sex

  prevented = contraception
• what is an example fungal disease and what are its characteristics?

  rose black spot (plant)

  symptoms = purple or black spots on leaves of rose plant

  spread = through water

  prevented = fungicides
• what is an example of a protist disease and what is its characteristics?

  malaria

  symptoms = fever and shaking

  spread = mosquitos

  prevented = vaccines
• how does the body act as a defence systems?

  the skin = physical barrier

  the nose = hairs and mucus to prevent particles entering

  trachea and bronchi = secrete mucus and cilia

  stomach = produces acid
• how do white blood cells work in the immune system?

  1. phagocytosis (engulf pathogens) = destroys pathogens
  2. produces antibodies
  3. produces antitoxins = neutralises toxins released by pathogen
• what is herd immunity?

  vaccinating a large proportion of the population, reducing the spread of the pathogen
• what is a vaccine and what does it contain?

  a vaccine is a substance that simulates white blood cells to produce antibodies complimentary to the antigens on the pathogen

  they contain dead or inactive pathogens
• what are two advantages of vaccines?

  eradicated diseases

  epidemics prevented
• what are two disadvantages of vaccines?

  side effects

  can take a long time to make successful vaccine
• What are antibiotics?

  medicines that kill bacterial pathogens without damaging the body cells
• how is bacteria becoming resistant to antibiotics?

  mutations can occur during reproduction resulting in certain bacteria no longer being killed

  this means only the non resistant bacteria dies, allowing resistant cells to reproduce and this resistant population increases
• how can we bacteria from becoming resistant?

  stop overusing antibiotics

  finishing courses of antibiotics to ensure all bacteria is killed so none can adapt
• what are examples of drugs that have come from plants?

  Aspirin = painkiller (from willow)

  digitalis = treat heart problems (from foxgloves)
• what is a microorganism that is used as a drug?

  Penicillin = first antibiotic

  found by Alexander Fleming
• why do drugs need to be tested before use?

  ensure they are safe and effective
• what are the stages of drug testing?

  preclinical testing = using cells, tissues and live animals

  clinical testing = using volunteers and patients

  peer review = ensure no mistakes
• what is done during clinical testing?

  first tested on healthy volunteers to ensure no harmful side effects

  next drugs tested on patients to find best dosage

  lastly patients are split into two groups with one receiving the drug other is placebo
• what is the placebo effect and what are the two types during clinical trials?

  placebo = fake drug to see how effective the real drug is

  these can be single blind where only the doctor knows if the patient is receiving the drug or double blind where both doctor and patient do not know if they are receiving the drug
• why is it important to have a double blind placebo trial?

  to remove any biases
• what are two deficiencies that can cause an issue in plants?

  Nitrate deficiency = stunts pant growth

  Magnesium deficiency = causes chlorosis (less chlorophyll which prevents photosynthesis)
• what are a plants defences?

  physical defences = waxy cuticle to stop microorganisms from entering leaves

  chemical defences = some plants have poisons

  mechanical defences = thorns and hairs