Starter questions Flashcards
Describe how macrophages process antigens for presentation on their cell surface membrane
Antigen fragments combined with MHC (special glycoproteins in cytoplasm)
What name is given to small protein molecules that act as cell-signalling compounds?
Cytokines
State three passive physical defences that prevent plants being infected by a pathogen
Bark, waxy cuticle, thorns, spines, lignified cell walls, cellulose.
State three factors that would affect the speed of disease transmission in plants
Overcrowding, poor mineral nutrition, damp warm humid conditions, climate change.
Describe the difference between herd vaccination and ring vaccination
Herd vaccination is where everyone (or almost everyone) is vaccinated. Ring vaccination is vaccinating people around the site of the outbreak, so that the pathogen will not be transmitted across that ring to the whole population.
Explain why passive immunity only provides short-term immunity
Passive immunity is provided by an external supply of antibodies - these are proteins and will not last long in the body. They may even act as antigens and be attacked by antibodies from our immune system
Antibodies are made by plasma cells. Explain how plasma cells are speciaised for their role.
Plasma cells have a lot of ribosomes, rough endoplasmic reticulum, golgi apparatus and mitochondria. Ribosomes for proteinsynthesis, golgi for vesicles.
Give an example of artificial active immunity
Immunity provided by antibodies made in response to vaccination (dead/inactive pathogens injected).
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.
Describe how antitoxins function.
Neutralise toxin molecules released by a pathogen through direct binding.
Where is bile stored?
Gall bladder
What is negative feedback?
A response that is opposite to the stimulus, returning conditions back to the optimum
What are 3 advantages of being ectothermic that are disadvantages to being endothermic
Ectotherms: use less energy from food for respiration, use more energy from food for growth, survive long periods without food
Name 4 physiological responses in an endotherm that lead to a decrease in temperature
Piloerection, vasoconstriction, increased liver metabolism, shivering
What is vasoconstriction?
Contraction of smooth muscle to narrow arterioles which restricts blood to the skin surface
