biology topic 3 - infection and response

• what is a communicable disease and give examples ?

  diseases that can spread - measles, HIV, rose black spot, salmonella
• what are pathogens ?

  microorganisms that enter the body and cause disease
• what is bacteria ?

  very small cells which can reproduce rapidly inside your body
• what are the 4 types of pathogens ?

  viruses, bacteria, fungi, protists
• what are protists ?


  single cell eukaryotes
• how can pathogens be spreaded ?

  water, air , direct contact
• what do viruses do ?

  they live and reproduce inside cells, causing cell damage
• what do parasites do ?

  they live on or inside other organisms causing damage
• when a viruses reproduces and produces many copies what happens to the cell ?

  the cell will burst, releasing all new viruses leading to illness
• what can hyphae do ? fungi


  grow and penetrate human skin causing disease
• what are the 3 viral diseases ?

  malaria, measles and HIV
• what is measles and how is it spreaded ?

  a viral disease and it is spreaded by droplets of an infected person's sneeze or cough
• what is HIV and how is it transmitted ?

  a virus spread by sexual contact or by exchaning bodily fluids such as blood. this can happen when people share needles when taking drugs
• what are infected people who have HIV given ?

  anitiretroviral drugs which can slow the development of aids
• what does HIV do to the cells ?

  it attacks the immune cells
• what is tobacco mosaic virus ?

  a widespread plant pathogen affecting many species of plants including tomatoes and it causes discolouration in plants which affects the growth of plants due to lack of photosynthesis
• what is rose black spot ?

  a fungus that causes purple or black spots to develop in the leaves on rose plants - the leaves turn yellow and there will be less photosynthesis
• what is malaria ?

  a disease caused by a protist , mosiquitoes
• what does the MMR vaccine contain ?

  weakened versions of the viruses that cause measles , mumps and rubella all in one vaccine
• what does HIV and AIDS stand for ?

  1. human immunedeficiency virus 2. acquired immune deficiency syndrome
• what are protists ?

  a group of microorganisms that have features that belong to animals, plants and fungi
• list the ways disease can be spread :

  coughing , sneezing, STD , direct touch, contaminated water
• what drugs are taken when you have malaria ?

  anitmalarial drugs
• what do mosquitoes do ?

  they suck the blood containing the protists from an infected person. they pass the protists to other people they suck the blood from
• what is salmonella ?

  genus of bacteria that causes food poisoning
• what can salmonella cause ?

  abdominal cramps, vomiting and diarrohea
• where can salmonella be found in ?

  unhygienic kitchens , contaminated food
• how do prevent salmonella ?

  all poultry should be vaccinated
• what is a vector ?

  any organism that can spread a disease
• what is gonnorohea ?

  a sexually transmitted disease caused by a bacteruim and it can be treated using antibiotics
• what does gonnorohea cause ?

  A burning pain when urinating and yellow, green discharge from an infected person's penis or vagina and if untreated can result to inferitlity
• how can whiteblood cells help to defend against pathogens by ?

  • phagocytosis , anitbody and anittoxin production
• what are parts of the human defence system ?

  1. skin- acts as a barrier and secretes antimicrobial substances to kill pathogens
  2. nose - hair and mucus trap particles containing pathogens
  3. trachea and bronchi- mucus traps pathogens, and cillia waft mucus up to the throat so that it can be swallowed
  4. stomach - hydrochloric acid kills pathogens
• what does the immune system do ?

  attacks the pathogens and uses white blood cells
• what is a vaccine ?

  an injection containing a dead or inactive pathogen
• what do the pathogens do ?

  carry antigens which cause your white blood cells to produce antibodies to attack them
• what do our own white blood cells produce in response to these antigens ?

  antibodies
• what the pros of vaccines ?

  • have helped control lots of infectious diseases, eg measles, rubella big outbreak of diseases, epidermics can be prevented if everyone is vaccinated
• what are the cons of vaccines ?

  they don't always work and there could be side effects
• what are painkillers ?


  drugs that relieve pain , reducing symptoms