Infection and response

  • Created by: benitaxx
  • Created on: 08-05-17 16:20
View mindmap
  • Infection and response
    • Pathogens and disease
      • Pathogens
        • Infections that cause communicable diseases
        • Can be spread by direct contact or through water and air
        • Vectors that carry and pass on pathogens without getting the disease
      • Viral pathogens
        • Viruses produce rapidly in body cells
          • Causes damage to cells
        • Measles
          • Symptoms are fever and red skin rash
          • Spread by breathing in droplets from sneezes and coughs
          • Can be fatal so most children are vaccinated
        • HIV
          • At first HIV causes a flu like illness but if left untreated,attacks the immune system
            • Taking anti-viral drugs can delay this
            • Once the Virus reaches late stage the body is unable to fight off infections or cancers
          • Spread by exchange of bodily fluids or sexual contact
      • Bacterial diseases
        • Bacteria can damage cells or produce toxins that damage tissues
        • Salmonella
          • Food poisoning caused by bacteris
          • Can come from food thats been cooked, stored or prepared incorrectly
            • Chickens are carriers so in UK are vaccinateed
          • Symptoms include fever, vomiting and diahorrea
            • Because bacteria secrete toxins
        • Ghonorrea
          • Spread through sexual contact
          • Thick yellow or green discharge and pain when urinating
          • Can be prevented using barrier methods of cotraception
          • Used to be treated with penicillin but resistant trains have now formed
      • Protists and disease
        • protists are single celled organisms
          • Eukaryotic
        • Malaria is caused by a protist
          • use a particular type of mosquito as a vector
            • When someone gets bitten It's passed on
          • Malaria causes a fever which can be fatal
          • To stop people being bitten they can use mosquito nets
      • Fungal diseases
        • Rose black spot
          • Spread when spores are carried plant to plant by water or wind
          • Purple and black spots develop on leaves
            • Turn yellow and drop
              • loss or leaves prevents photosynthesis and stunts growth
          • Can be treated by using fungicides and destroying leaves
    • Human defences
      • Body's defences
        • Enzymes in tears destroy microorganisms
        • Nose traps particles the may  contain pathogens
        • Glands in stomach produce hydrocholoric acid, killing bacteria in food
        • Sebaceous gland in skin produces sebum which kills bacteria and fungi
      • Immune system
        • immune system tries to destroy pathogens
        • Phagocytosis
          • Microorganism enters body
            • White blood cell finds microorganism and engulfs it
              • White blood cell ingests microorganism
                • microorganisms have been digested and destroyed
        • White blood cells can defend by producing antibodies
          • Antigens are markers on surface of microorganisam
            • White blood cells become sensitised to antigens and produce antibodies
              • Antibodies lock onto antigens
                • Causes microorganisms to clump together so they can be easily ingested
        • White blood cells can also produce antitoxins which neutralise poisonous affect of toxins
      • Boosting immunity
        • If the same pathogen reenters the body, the white blood cells respond quicker
        • By giving a vaccination, a small, inactive amount of the disease is injected
          • Once injected, it stimulates white blood cells to produce antibodies
            • The white blood cells that are capable of quickly producing specific antibodies stay in the blood stream
              • If a large proportion of the population can be made immune to a pathogen, it can't spread easily
    • Treating diseases
      • Antibiotics can treat bacterial infections but not viral infection
      • Bacterial strains resistant to antibiotics are increasing
        • Called MRSA
        • Patients should complete full course of antibiotics so no bacteria survives to form a resistant strain
        • Doctors should not prescribe antibiotics for viral infections or non-serious infections
      • Required Practical: place discs soaked in antibiotics on Agar. Incubate at 25 degrees for a few days
        • Greater the area around each disk clear of bacteria, the better the antibiotic
      • Drug development
        • Drugs have to be tested to check they are safe before use
          • They are then tested to see if they work and to find the optimum dose
        • Double blind trials are carried out
          • Some patients are given placebo, some are given real drug. Neither doctors or patients know what each person has
      • Monoclonal Antibodies
        • Produced from a single cell that has cloned it's self
          • Produced by combing mouse cells and tumor cells to make a cell called a hybridoma
        • Only bind to one type of antigen so can only be used to target specific chemicals or cells
        • Can be used for
          • Pregnancy tests
          • Labs to measure hormones or pathogens in blood
          • To treat some diseases such as cancer
        • Due to having more side affects than expected, they are not widely used
    • Plant disease
      • Detecting and identifying plant disease
        • Stunted growth
        • Spots on eaves
        • Areas of decay
        • Discolouration
        • Growths
        • Abnormal leaves or stem
        • Presence of pests
        • To identify disease  look on gardening websites, take plants to a lb to identify pathogen or use a testing kit
      • Tobacco mosaic virus
        • Infects many plants including tobacco and tomatoes
        • Discolouration leaves causing reduction in phtosynthesis
          • This affects plant growth
      • Aphids are small insects
        • Feed from phloem, taking sugars away from plant
      • Deficiency diseases
        • caused by a lack of mineral ions in the soil
        • Stunted growth is caused by nitrate defficiency beacuse nitrates are needed for photosynthesis
        • Chlorosis is caused my magnesium deficiency because magnesium ions are needed to make chlorophyll
      • Plant Defences
        • Physical
          • Cellulose cell walls
          • Tough waxy cuticle on leaves
          • Layers of dead cells which fall off and take pathogens with them
        • Chemical
          • Antibacterial chemicals
          • Poisons to deter herbivores
        • Mechanical daptations
          • Thorns and hairs to deter animals
          • leaves that droop or curl when touched

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cells, tissues and organs resources »