4.1.1 communicable diseases, disease prevention and the immune system Flashcards
what is a communicable disease
a disease that can be spread between organisms
what is a disease
a condition that impairs the normal functioning of an organism
what type of pathogen causes tuberculosis
bacteria
how is tuberculosis spread
droplets from an infected individuals coughs/sneezes
how can we reduce tuberculosis transmission
vaccination and less crowded living conditions
how do we treat tuberculosis
antibiotics
what type of pathogen causes meningitis
bacteria
how can we reduce meningitis transmission
vaccination and less crowded living conditions
how is meningitis spread
droplets from an infected individuals coughs/sneezes
how do we treat meningitis
antibiotics
how is ring rot spread
direct contact, wind and water, soil and via pests/animals
what type of pathogen causes ring rot
bacteria
how can we reduce ring rot transmission
insecticides/fungicides
fertilizers
washing hands/tools/machinery
remove infected species
crop rotation
antibacterial/antivirals
keep animals and pests away
how do we treat/prevent ring rot
no cure but can reduce spread to other plants
what pathogen causes influenza
virus
how is influenza spread
droplets from an infected individuals coughs/sneezes
how do we prevent/treat influenza
vaccination, good hygiene
antiviral drugs
what pathogen causes HIV
virus
how is HIV transmitted
contact of bodily fluids
how can HIV be prevented/treated
no cure
immunosuppressants
prevented by barrier protection and education
how do we prevent/treat TMV
no cure
prevented by
insecticides/fungicides
fertilizers
washing hands/tools/machinery
remove infected species
crop rotation
antibacterial/antivirals
keep animals and pests away
what pathogen causes tobacco mosaic
virus
how is TMV spread
direct contact, wind and water, soil and via pests/animals
what pathogen causes malaria
protist
how do we prevent/treat malaria
limiting contact with vectors with nets/insecticides
medicine
how is malaria spread
spread by mosquitos as a vector
what pathogen causes late blight
virus
how is late blight transmitted
direct contact, wind and water, soil and via pests/animals
how is late blight prevented/treated
insecticides/fungicides
fertilizers
washing hands/tools/machinery
remove infected species
crop rotation
antibacterial/antivirals
keep animals and pests away
what pathogen causes athletes foot
fungi
how is athletes foot spread
direct contact with infected skin or spores
how is athletes foot prevented/treated
fungal creams
prevent going barefoot in damp areas
what pathogen causes black sigatoka
fungi
how is black sigatoka spread
direct contact, wind and water, soil and via pests/animals
how is black sigatoka prevented/treated
insecticides/fungicides
fertilizers
washing hands/tools/machinery
remove infected species
crop rotation
antibacterial/antivirals
keep animals and pests away
what is the structure of a virus
they have no cell structure and connot preform cellular functions
how to viruses cause disease
they in vade host cells and use them to replicate. the cells then burst releasing more viruses. the damage to cells causes us too feel symptoms
what are protists
unicellular eukaryotes which are often spread by vectors
what are fungi
they have filaments called hyphae which form a network in the host/soil
how does overcrowded living conditions spread disease
if one person gets a disease it will spread easily due to close proximity to other people
how can climates effect disease transmission
some diseases are more common during wet summers so spores can be spread in water
certain vectors like specific climate conditions
what is the primary non specific immune response
defences that have been adaptions to prevent disease from happening
what is the role of skin in the non specific immune response
it acts as a physical barrier blocking pathogens from entering. it also acts as a chemical barrier because it secretes antimicrobial chemicals which lower skin pH
what is the role of mucous membranes in the non specific immune response
they protect body openings that are exposed. mucous traps pathogens and contains antimicrobial membranes
what is the role of blood clotting in the non specific immune response
they plug wounds to stop pathogens entering. formed from a series of chemical reactions that take place when platelets are exposed to damaged blood vessels
what is the role of inflammation in the non specific immune response
damaged tissue releases molecules which increase the permeability of blood vessels so that more tissue fluid is formed.
this isolates pathogens and cause vasodilation making the area warm and increases blood flow
what is the role of wound repair in the non specific immune response
the skin surface is repaired by outer layer of skin cells dividing and migrating to edges of he wound. the tissue below contracts to bring the edges closer. it is repaired using collagen fibres
what is the role of expulsive reflexes in the non specific immune response
a sneeze happens when the mucous membrane in the nose re irritated by things, a cough happens when there is irritation in the respiratory tract. these happen automatically
what are some physical plant defences against disease
waxy cuticle - physical barrier stops water collecting on leaves
cell walls - physical barrier
produce callose - deposited between cell wall and membrane or at plasmodesmata during stress
what are some chemical plant defences
producing antimicrobial chemicals
saponins and phytoalexins destroy cell membranes and inhibit growth of pathogens
secrete toxins to kill pests
what is the specific immune response
it is antigen specific so it is aimed at different pathogens
what are neutrophils
they are a type of white blood cell which are the first to respond to an infection due to signals from cytokines from damaged cells
what are macrophages
after ingesting a pathogen it presents antigens on its surface triggering the specific immune response
what is phagocytosis
the engulfment and digestion of pathogens
how des phagocytosis work
a phagocyte recognises an antigen as non self. the cytoplasm moves around the pathogen engulfing it. this is helped by opsonins
this is called a phagosome
a lysosome fuses with the phagosome and the digestive enzymes break it down
the phagocyte then presents the antigens on its cell membrane acting as an antigen presenting cell
what is the cell mediated specific response and what happens during it
the antigen presenting cell binds to specific receptors o a T lymphocyte. this activates the t lymphocyte in clonal selection
the t cell then goes through clonal expansion where it divides to produce clones of itself
it then differentiates to form different types of t lymphocytes
what do T helper cells do
they release substances to activate B lymphocytes and T killer cells
what do T killer cells do
they kill infected cells and kill pathogens by releasing perforins
what do T regulatory cells do
they suppress the immune response so they do not attack the host cells
what do memory cells do
remember the response to a specific antigen so that the person is immune
what is the cell humoral specific response and what happens during it
the antibodies on the surface of a B lymphocyte bind to the antigens to form antigen-antibody complexes. this with substances secreted from T helper cells activates the B cell. this is clonal selection
it then divides into plasma cells and memory cells in clonal expansion
what are plasma cells
they make and secrete antibodies
what is an antibody
glycoproteins
what is the structure of an antibody
4 polypeptide chains - 2 heavy and 2 light
each chain has a variable region specific to each antibody and a constant region.
the hinge region allows flexibility when the antibody binds to the antigen
disulfide bridges hold the chains together
how do antibodies agglutinate pathogens
each of the two binding sites binds to a different pathogen grouping them all together so a phagocyte can engulf them all at once
how do antibodies neutralise toxins
antibodies complementary to the toxins bind to them preventing them damaging cells
how do antibodies prevent pathogens from binding to human cells
when antibodies bind to antigens it may block cell surface receptors that pathogens need to bind to host cells
what is the primary response
the immune response when you come into contact with the pathogen for the first time
what is the secondary response
the immune response when we have already come into contact with a specific pathogen
what is different about the primary and secondary responses
primary has a delay where we feel the symptoms when antibodies are being made. this delay is not in the secondary response as we have memory cells
what is an example of passive, natural immunity
antibodies passed down from the mother through blood or breast milk
what are passive and active immunity
active is when your body makes its own antibodies after stimulation from a pathogen
passive is when we are given antibodies from a different organism
what is an example of active, natural immunity
when you become immune after catching the disease
what is an example of passive, artificial immunity
when you become immune after antibodies from someone else are injected
what is an example of active, artificial immunity
when you are given a vaccination
how do vaccines work
we are injected with dead or inactive pathogens that simulate the immune response forming memory cells
why do some vaccines change regularly
some diseases mutate quickly so new vaccines are needed to target them as they become inefficient
what is herd immunity
when most of the population get the vaccine it means people who aren’t vaccinated are less likely to get it
what is an autoimmune disease and how are they treated
they recognise self antigens as foreign and coordinate an immune response against its own tissues
what are antibiotics
chemicals that kill or inhibit the growth of bacteria
what are the advantages and disadvantages of antibiotics
they can kill bacterial cells without damaging normal cells
antibiotic resistance
allergic reactions
how can we overcome antibiotic resistance
developing and modifying antibiotics
doctors encouraged to reduce their use of antibiotics and patients advised to finish the full course of antibiotics
what is antibiotic resistance
when variation in bacteria means some may have resistant genes. natural selection means that these breed so there becomes populations which are resistant and some antibiotics do not work for them
why must we protect biodiversity for healthcare
many medicines come from natural compounds found in plants, animals and microorganisms
what does the future of medicine look like
can use genetics to predict what drugs will work best
synthetic biology applied to medicine
