immunity Flashcards
(25 cards)
what is the structure of bacteria?
- single celled prokaryotes
- cytoplasm that lacks membrane-bound organelles
- no nucleus - single circular bacterial chromosome (free in cytoplasm)
- cell wall contains glycoprotein peptidoglycan
- loops of DNA - plasmids
what is the function of capsules in a bacteria cell?
protect bacteria from drying out and from attack by cells of the immune system of the host organism
what is the function of the flagellum in a bacteria cell?
for movement
what is the function of pili in bacteria cells?
enable the bacteria to attach to other cells or surfaces
what is the structure of viruses?
- non cellular infectious particles
- nucleic acid core
- protein coat ‘capsid’
- do not have plasma membrane, cytoplasm or ribosomes
- envelope (outer layer)
- proteins inside capsid
- attachment proteins
what are infectious diseases caused by?
pathogens
what is the function of attachment proteins?
enables virus to attach itself to a host cell
what are types of pathogens?
bacteria, some fungi and all viruses
what are T cells?
type of white blood cell involved with specific immune response
when are T cells activated?
when they encounter and bind to their specific antigen on the surface of an antigen presenting cell
what do T helper cells do?
release chemical signalling molecules that help to activate B cells
what do T killer cells do?
bind to and destroy infected cells displaying the relevant specific antigen
what do T memory cells do?
they remain in the blood and enable a faster specific immune response if the same pathogen is encountered again in the future
what are B cells?
second type of white blood fell in the specific immune response
where are B cells found?
bone marrow
what do B cells have on their cell surface membrane?
antibody receptors
when do B cells bind to the antigen?
if the corresponding antigen enters the body, B cells with the correct cell surface antibodies recognise and bind to it —-> antigen - antibody complex
how does the B cell divide?
mitosis
what does the cell division of the B cells produce?
many clones of the original activated B cell
what are the two types of B cells?
- memory cells
- plasma cells
function of plasma cells?
produce specific antibodies to combat non-self antigens
function of memory cells?
remain in blood to allow a faster immune response to the same pathogen in the future
what are the entry routes of pathogens?
- broken skin
- the digestive system
- the respiratory system
- mucosal surfaces
what are barriers to infection?
- skin
- microorganisms of gut and skin
- stomach acid
- lysozyme
