topic 4.1.1: communicable disease, prevention and immune system Flashcards
give 3 physical plant defences against disease
waxy cuticles, cell walls, production of callose (deposited between cell walls and membranes to reinforce)
give 4 chemical plant defences against disease
insect repellent, insecticides, antibacterial substances, toxins
what are T lymphocytes/cells?
mature in thymus gland, involved in cellular response by responding to antigens presented by cells
what are B lymphocytes/cells?
mature in bone marrow, involved in humoral response, have antibodies on surface, become APCs
what are the 4 types of T cells?
helper (receptors that bind to comp antigen, produce interleukins, can form memory or killers)
killer (kill abnormal cells)
regulator (suppress immune system)
memory (long term immunity)
what can B cells divide into?
plasma cells- produce and secrete antibodies
memory cells- rapidly divide into plasma cells if infection occurs again
what are interleukins?
chemical signalling molecules that stimulate B cells
what is clonal selection?
selection of B cell with correct antibody form cloning (by being activated by T helper)
what is clonal expansion?
division of specific B cells
what are agglutinins?
chemicals that cause pathogens to stick together
what are cytokines?
chemicals released by phagocytes that have engulfed a pathogen to trigger others
what are opsonins?
chemicals that bind to and tag foreign cells, making them easily recognisable to phagocytes eg antibodies
what are the two types of phagocytosis?
neutrophils- engulf and destroy pathogens at site of infection
macrophages- engulf and digest, also act as APC
describe the process of phagocytosis
phagocyte recognises antigens as non self and binds
phagosome (vacuole) created inside and fuses with lysosome to digest
phagocyte presents antigens
what is the humoral response?
involves production of specific antibodies from B cells in body fluids
