Topic 3: communicable diseases

• Viruses

  • very small
  • move into cells to make copies of itself
  • leads to cells bursting and releasing into bloodstream
  • damage and destruction of cells making you feel ill.
• Bacteria

  • small
  • multiply very quickly through binary fission
  • produce toxins that damage cells
• Protists

  • malaria via mosquitoes
  • vectors
• fungi

  • single celled
  • using pesticides
• Measels

  • fever, red skin rash
  • droplet infection
  • vaccinations to reduce transmissions
• HIV

  • flu-like cold, the virus attacks the immune system
  • sexual contact and exchange in body fluid
  • use contraception
• Tobacco mosiac virus

  • discolouration of leaves, cannot photosynthesis
  • contact between diseased plants
  • pest control
• Salmonella

  • fever, stomach cramps, vomiting
  • contamination of foods
  • keep raw meat and cooked meat separate
• Gonnoreha

  • thick yellow discharge from the genitals
  • STD through unprotected sex
  • use contraception
• Rose black spot

  • purple black spots on leaves
  • reduces photosynthesis
  • water or wind spread
  • using fungicides
• Malaria

  • fever
  • vector reproduces sexually
  • protist enters the blood via their saliva
• Malaria cycle

  • mosquito feeds off blood
  • becomes a host
  • mosquito travels to uninfected animal and feeds on blood
• Skin defence system

  • acts as a physical barrier
  • produces antimicrobial secretations to kill pathogens
• The nose defence system

  • Hair and mucus to trap pathogens
• The trachea and bronchi defence system

  • secrete mucus to trap pathogens
• The stomach defence system

  • produces hydrochloric acid to kill bacteria
• Phagocytosis

  • white blood cell englufs pathogen
  • produces toxins and antibodies
  • phagocyte travels towards bacterium
  • Releases cytoplasm to surround it
  • Bacteria is then engulfed and killed
• A vaccination involves making someone immune to a certain disease
• Herd immunity is immunising a large population to reduce the spread of the pathogen
• The vaccine contains weak or inactive pathogen which stimulates the white blood cells to produce antibodies to the antigens of the pathogen
• Vaccinations are not always effective

  bad reactions can occur]
• Vaccinations have helped many diseases and reduced the occurance of many, epidemics have been prevented through herd immunity
• • antibiotics can be taken as a pill which goes directly to the bloodstream
  • Antibiotic ressistant, doesn't affect the bacteria
• Mutations can happen during reproduction and certain bacteria is no longer being killed
• Digitallis comes from foxglove
• asprin comes from willow tree
• penecillin comes from penicllum fungus
• Pre-clinical testing uses tissues, cells and living animals
• Clinical testing uses volunteers and patients

  • tested on healthy volunteers to ensure no side effects
  • Drug is tested in patients to find most effective dosage
  • one may receive a placebo so the effect of the new drug can be preserved
• monoclonal antibodies are identical antibodies that have been produced from the same immune cell
• Monoclonal antiboides
• monoclonal antibodies are produced by obtaining mice lymphocytes which produce a specific antibody. Combine with tumor cells
• Pregnancy tests

  • HCG is present in the urine of women
  • a section of the stick has mobile antibodies which attach to blue beads
  • stationary antibodies which are stuck to the stick
  • if pregnant the mobile antibodies form HCG complexes
• • Cancer cells have antigens on the cell membrane called tumour markers
  • They produce monoclonal antibodies which bind to tumour markers
  • also they bind to receptor sites on a cell membrane
  • use to transport drugs as they only bind to cancer cells
• Advantages of monoclonal antibodies

  • Bind to specific cells, healthy cells not effected
  • treat many conditions
  • produce mouse human hybrid cells
• Disadvantages of monoclonal antibodies

  • difficult to attach to drugs
  • expensive to develop
• common signs of plant disease

  • stunted growth
  • spots on leaves
  • area of decay
  • abnormal growth
  • malformed stems/leaves
  • discolouration
• Nitrate deficiency

  • stunts growth
  • in soil
  • proteins needed for growth
• Magnesium deficiency

  • causes chlorosis
  • needed to make chlorophyll
  • vital in photosynthesis
• Mechanical defences on plants

  • Thorns/ hairs is difficult to animals to eat
  • some leaves drop
  • mimicry to trick animals