disease lesson SLOP Flashcards
State the kingdom of organism that causes each of the following diseases: tuberculosis, Black Sigatoka, Athlete’s foot, malaria
Bacteria, fungi, fungi, protoctists
State the kingdom of organism that causes each of the following diseases: blight, ringworm, ring rot, bacterial meningitis
Protoctists, fungi, bacteria, bacteria
Give one plant disease caused by each of each following virus, bacteria and fungi
Tobacco mosaic virus, ring rot, black sigatoka
state how the influenza virus is most likely to be transmitted between different humans
Respiratory droplets (inhalation)
state four different types of vector that can be used to transmit a communicable disease
Water (e.g. diarrhoeal diseases); animals (e.g. mosquito transmits Plasmodium); wind (carries spores); humans (hands, clothing etc.)
State three physical defences that prevent plants being infected by a pathogen
passive Bark, waxy cuticle, thorns, spines, lignified cell walls, cellulose etc.
state 3 active physical defences a plant would employ against an invading pathogen
Callose synthesised and deposited between plasma membrane and cell wall; callose blocks sieve plates in phloem; callose deposited in plasmodesmata between infected cells and their neighbours; lignin added to cell walls; tyloses block xylem vessels
state 3 chemical defences a plant would employ against an invading pathogen
Antibacterial compounds like phenols, alkaloids; terpenes; hydrolytic enzymes like glucanases and chitinases; caffeine; tannins etc.
describe the role of the skin as a primary non-specific defence
Dead outer layer of keratin prevents pathogen entry; skin flora outcompete pathogens for space; oil secretions inhibit pathogenic growth
describe the role of mucous membrane as a primary non specific defence
Mucus traps pathogens and contains lysozymes; phagocytes engulf and digest pathogens in mucus
which enzyme catalysed the conversion of prothrombin to thrombin
Thromboplastin (thrombokinase)
describe the role of thrombin in the clotting process
Causes the conversion of soluble fibrinogen into insoluble fibrin fibres
describe the process of inflammation as a secondary non-specific response
Mast cells release histamines; histamines increase permeability of capillaries meaning plasma leaks into tissue fluid (pain and swelling); vasodilation of arterioles so more blood reaches infected area (heat and redness); neutrophils attracted to area for enhanced phagocytosis
describe the process of phagocytosis
Phagocyte engulfs pathogen into a phagosome; lysosomes fuse with phagosome to form a phagolysosome; enzymes, hydrogen peroxide and nitric acid break down the pathogen
describe how macrophages process antigens for presentation on their cell surface membrane
Antigen fragments combined with MHC (special glycoproteins in cytoplasm)
what is name given to small protein molecules that act as cell-signalling compounds?
cytokines
describe how neutrophils are specialised for their role
contains receptors for opsonins, well developed cytoskeleton for phagocytosis, many mitochondria for respiration, many ribosomes to make enzymes, many lysosomes, many Golgi
opsonins are non specific. explain why.
Opsonins can attach to many types of pathogen and help the process of phagocytosis, by giving the phagocyte something to bind to. They must be non-specific, so they can attach to many different pathogens.
where do B and T lymphocytes mature?
Bone marrow and thymus respectively
what is meant by the term ‘autoimmunity’ and give two examples of autoimmune diseases
Destruction of self-tissue; rheumatoid arthritis, lupus, type I diabetes
what is the role of T regulatory cells
Dampen down the immune response; prevents destruction of self tissue (autoimmunity)
describe how an antigen presenting cell leads to large numbers of T helper cells
APC binds specifically to a Th cell (clonal selection). This selected Th cell then proliferates by mitosis (clonal expansion)
describe how b lymphocytes are activated and the role of activated B lymphocytes
The cell binds specifically to B lymphocyte; B lymphocyte differentiates into a plasma cell. Plasma cells release antibodies specific to the particular antigen