communicable diseases

• bacteria

• destroys lung tissue, suppresses immune system, cough, high temp

• spread through air

• cured by antibiotic

• prevented by improving living conditions and vaccinations

• bacteria

• high temp, headaches, rash, stiff neck, drowsiness

• spread through human contact

• cured by antibiotics and fluid and oxygen

• prevented through vaccinations

• bacteria

• vascular wilt, discolouration, loss of texture

• infected by daughter tubers from infected seeds

• no cure

• prevented through clean equipment and destroying infected plants

• fungus

• black brown streaks, can’t photosynthesise

• transmitted through spores and rain splashes

• treated with fungicides

• prevented with fungicides, good husbandry and removing affected leaves

• fungus

• ring shaped rash, itchy, scaly, slightly raised

• transmitted through direct contact

• treated with anti-fungal creams

• prevented through clean and dry skin, not walking barefoot, clip nails, air circulation

• fungus

• cracking and scaling, soreness, itching

• transmitted with direct contact

• treated with antifungal cream

• prevented with dry and cool feet, avoid using public water

• protoctist

• nausea, vomiting, fever, chills, headache, joint pain

• transmitted by anopheles mosquitos

• cured by anti malarial medicine

• prevented by abounding stagnant water, insecticides, mosquito nets

• protoctist

• small water soaked spots, discolouration

• transmitted through spores and direct contact

• cured by removing and destroying infected part and spraying fungicide

• prevented by spraying fungicide

• virus

• fever, headache, rash, diarrhoea, sore throat

• transmitted through bodily fluids, unprotected sex, shared needles, breast feeding

• no cure but anti retroviral drugs can slow the process

• prevented through avoiding reasons for transmission and pre and post exposure prophylaxis

• virus

• high temp, cough, headaches

• tranmistted through surfaces or airborne droplets

• cured with antiviral drugs and rest

• prevented through the flu vaccine and washing regularly

• virus

• stunted growth, mosaic pattern of dark and light green on leaves, damage

• transmitted through contact of infected area

• no cure

• prevented through disinfectant and removing infected areas

pathogens are passed on through direct contact between the infected and uninfected

pathogens are transmitted by means of another method of transport like vectors

transmits pathogens from one host to another without getting infected

transmission of pathogens through inanimate objects

inhalation of droplets containing moisture

eating contaminated food or drink

a break in the skin where pathogens can enter

infected plants leave pathogens and reprodcutive spores in the soil

bacterial, fungal, viral and oomycete spores can be carried in the wind

• susceptibility of disease

• overcrowding

• resistance e.g. poor mineral content reduce resistance

• climatic condition e.g. damp, warm increase spread

• climate change

• leave room between plants

• remove all traces of plant when harvesting

• rotate crops / host plants

• strict hygiene practices

  • control insect vectors

• molecules in pathogen are recognised

• pathogenic enzyme breakdown products are recognised by receptors in cell membrane

• signalling molecules alert nucleus

• polysaccharides (calls and lignin) strengthen cell wall

• defensive chemicals alert other cells

• defense molecules directly attack pathogen

• when pathogen is detected plants production of callose increases

• polysaccharide made of beta glucose monomers

• deposited between cell membrane and wall next to infected cells as a physical barrier

• adds lignin to strengthen barrier

• deposited in sieve cells and in plasmodesmata to prevent spread

• insects act as vectors

• pine resin citronella acts as repellant in lemon grass

• pyrethrins and caffeine act as insecticides

• antibacterial compounds contain antibiotics

• cotton plants produce phenols which is an antiseptic

• the plant proteins defensins disrupt membranes of bacteria and fungi

• produce anti fungal compounds

• gossypol produced by cotton

• caffeine is toxic to fungi and insects

• chemical in cell membrane called saponins which interfere with fungal membranes

• chitinases break down fungal membrane

• glucanase breaks down glucans found in oomycetes

• cyanide is toxic to most organisms

• produces sebum which inhibits pathogen

• physical barrier

groups of cells, tissues, organs and mechanisms that defend an organism against pathogens and other foreign substances

complex series of specific and non specific processes involving a range of cells and chemicals

natural healthy bacteria on skin and in stomach acid which outcompete pathogens

• trap pathogens which contain lysozymes that destroy bacteria

• cilia waft mucus up the trachea

enzymes in tears, urine and stomach fluid which destroy bacteria

eject pathogens laden with material from gas exchange or gut

e.g sneezing, coughing, vomiting

pathogens may enter the blood when skin is ruptured

• platelets rush to site of rupture

• release thrombroplastin and serotonin

• the clot dries forming a scab

• epidermal skin cells grow beneath skin

• collagen fibres reinforce skin cells

enzyme which triggers reaction

e.g. soluble fibrinogen and thrombin create insoluble fibrin

causes muscles top contract around the wound to close the gap

• swelling of skin immediately around the rupture

• causing pain, heat and swelling

• mast cells are activated when a rupture occurs which release histamines and cytokines

make blood vessels dilate causing heat and redness which stop pathogens reproducing

• increase permeability of cell membrane allowing more tissue fluid to escape causing swelling

• attract white blood cells

• normal body temperature is 37 controlled by the hypothalamus

• white blood cells cause hypothalamus to reset increasing temperature which stops pathogens reproducing

enzyme that disrupts cell wall of gram positive bacteria by digesting the peptidoglycan

protein produced by virus infected body cells which trigger production of another protein which inhibits viral replication by binding to mRNA coded by the virus

protein molecules produced by phagocytes which tag pathogens as foreign to encourage phagocytes to engulf

specialised white blood cells

• breaks down the foreign antigens of the pathogen

• foreign and macrophage antigens bind forming a MHC in the cytoplasm

• antigens are then displayed on the plasma membrane forming an APC

histocompatibility-complex

antigen presenting cell

• pathogens produce chemicals that attract phagocytes

• phagocyte engulfs pathogen and puts it in a phagosome

• phagosome and lysosome combine forming a phagolysosome

• enzymes in phagolysosome break down pathogens

• pathogen exits phagocyte by exocytosis

a specialised vacuole

• chemical released by phagocytes after engulfing a pathogen

• cell signalling molecule

• stimulate other phagocytes to move towards site of infection

• can increase body temp

• can stimulate specific immune response

specialised glycolipids and glycoproteins acting as foreign protein markers

• can be recognised as foreign stimulating an immune response

• specialised glycoproteins called immunoglobulins

• specific and bind to one type of antigen in lock and key model

• produced by immune system

• agglutination - sticks pathogens together identifying them for pahogocytosis

• prevent pathogens from entering cells

• act as opsonins to tag pathogens

• neutralisation of toxins

disulphide bridge maintaining the tertiary structure of the antigen

antigen binding site

light polypeptide chain

variable region complementary to specific antigen

constant region

when one antibody binds to two pathogens causing them to clump together which make the iatrogenic more easily engulfed

antibodies can act as antitoxins binding with pathogen toxins making them harmless

they recognise antigen molecules on the surface of pathogens and coordinate the immune response

• b lymphocytes

• t lymphocytes

• cell mediated immune response

• destroy cells of your body that have been infected and early stage cancer cells

• produced in bone marrow but matured in thymus

• t helper cells

• t killer cells

• t memory cells

• t regulator cells

• produce interleukins, a type of cytokine

• stimulate b lymphocyte cells

• increase antibody production

• attract and stimulate phagocytes to ingest pathogens

• kill cells infected by pathogens

• produce perforin which skews holes in the plasma membrane of infected cells

• act as immunological memory

• remain in the blood for a long time

• when second infection occurs they divide rapidly forming killer t cells

• prevent autoimmune response

• Auspressen immune system after all pathogens are destroyed

• humoural immune response

• identifies and destroys pathogens in your blood and tissue fluid

• produced and matured in the bone marrow

• plasma cells

• b effector cells

• b memory cells

• produce specific antibodies to invading antigen

• divide to form plasma cell clones to form any b lymphocyte cells

• remain in blood for long time

• provide immunological memory

• reproduce quicker on second infection with the same antigen

• macrophages engulf pathogens by phagocytosis becoming antigen presenting cells

• specific t helper cells with receptors bind with the macrophages antigens

• clinal selection

• t helper cell produces interleukins and stimulate more production of t cells

• clonal expansion

• cloned t cells become any t cell

• macrophages present antigen to t helper cell

• t helper cells release interleukins

• activate specific b effector cells

• clonal selection

• selected b cells divide

• clonal expansion

• the cloned plasma cells produce specific complementary antibodies that bind to pathogen

• agglutination or neutralisation occurs

• b memory cells rapidly divide to produce plasma cells

• much faster response as antigen doesn’t need to be identified

when the immune system stops recognising self antigens and attack healthy body tissue

• normal immune response

• produces b and t lymphocytes producing antibodies

• vaccination where dead attenuated pathogen is injected

• encourages body to produce antibodies

• given to child during pregnancy and breastfeeding

• gain antibodies however will not last log as they are non self

• antibodies produced by another organism is injected into the blood stream

• short lasting immunity

• e.g. tetanus

• contain inactivated form of pathogen where the immune stimulating antigens are intact

• contain attenuated form of pathogen

• contain only isolated antigens like cell surface proteins

• antigen is injected into blood stream with no infection

• immune response triggered

• specific b cells bind to antigen

• b cells are cloned to form plasma cells

• antibodies produced

• some b cells become memory cells

• short secondary immune response on infection

when a communicable disease spreads throughout a national level

when a communicable disease spreads throughout a international level

vaccinating a large proportion of the population to reduce spread

vaccinating only people who are most at risk

• malaria - plasmodium protocist causes the disease to hide in erythrocytes so are protected from immune system

• HIV / AIDS - virus infects and disables the immune system

• mainly from tropical plants, bacteria or fungi

• use existing defences of those organisms

• strong argument to maintain biodiversity

• personalised medicine that works with your specific genetics and disease

• looks at genome of patient and pathogen before treating

• already know genotypes and drugs interact from breast cancer mutation of HER2 gene

• bactericidal - kill bacteria cells

• bacteriostatic - slow the reproduction of bacteria

• only give antibiotics when needed

• patients should complete full course

• infection control in hospitals

• mutation or variation in bacteria population

• antibiotics apply selection pressure

• mutated bacteria are naturally selected

• only mutated bacteria survive