longer answers PAPER 1

Question 1

how do pregnancy tests work?

Answer 1

• the part you wee on has mobile antibodies to HCG with blue beads attached
• the test strip has stationary antibodies as they are stuck onto the strip
• HCG binds to the antibodies on the blue beads
• the urine moves up the stick carrying the hormone and the beads
• the beads and HCG bind to the antibodies on the strip
• the beads get stuck on the strip making it have 2 blue lines

Question 2

how are monoclonal antibodies made?

Answer 2

• inject a mouse with the chosen antigen
• B-lymphocytes are taken from the mouse
• B-lymphocyte is fused with a tumour cell to form a hybridoma
• this divides quickly to produce lots of clones that produce monoclonal antibodies

Question 3

what is the lytic pathway?

Answer 3

• virus attaches itself to a host cell and injects its DNA
• it uses the cell’s components to build new viral components
• a new virus assembles in the host cell
• the host cell splits open releasing the new viruses

Question 4

what is the lysogenic pathway?

Answer 4

• the injected genetic material is incorporated into the DNA of the host cell
• viral genetic material gets replicated along with the host cell
• virus is dormant and no new virus is made
• a trigger causes the virus to leave the genome and enter the lytic pathway