biological processes paper 1

Question 1

what are the stages of phagocytosis?

Answer 1

1) phagocytosis is carried out by a type of white blood cell called a phagocyte
2) first the phagocyte track down a pathogen and then binds to it
3) the phagocyte’s membrane will then surround the pathogen and engulf it
4) finally, the enzymes inside the phagocyte break down the pathogen in order to destroy

Question 2

what are the stages of drug development?

Answer 2

stage 1 - test the drug on human cells and tissues
stage 2 - test the drug on live animals
stage 3a - test the drug on healthy volunteers to find the maximum dosage before side effects occur
stage 3b - test the drug on patients that suffer from the relevant disease (using double blind trials), to find the optimum dosage

Question 3

how do you produce monoclonal antibodies?

Answer 3

1) inject an animal, like a mouse, with an antigen that we want our antibodies to bind to
2) let the animal develop an immune response, and then isolate some of their b-lymphocyte cells (which produce the antibody that we want)
3) combine those b-lymphocyte cells with fast-dividing tumour cells to form hybridoma cells
4) let the hybridoma cells divide rapidly in a petri dish
5) collect and purify the monoclonal antibodies they produce

Question 4

how does a pregnancy test work?