Section 2, ,cells mark scheme

Question 1

What are monoclonal antibodies

Answer 1

Antibodies with the same tertiary structure
Or
Antibodies produced from b cells

Question 2

An example of monoclonal antibody use in medical treatment

Answer 2

Carries drug to specific cells
Or
Blocks antigens/receptors on cells

Question 3

Describe the role of antibodies in producing a positive result in an ELISA test

Answer 3

• first antibody is complementary to the antigen and binds to it
• second antibody with enzyme attached is added
• second antibody attaches to the antigen
• the substrate is added and the colour changes

Question 4

For onion root mitosis observation, why are only the first 5mm used, and why is it pressed down firmly

Answer 4

• mitosis occurs at the tip
• thin layer of cells allows light to pass through

Question 5

Describe one difference between the structure of DNA in a prokaryotic cell and in a eukaryotic cell (1)

Answer 5

Prokaryotes are
- circular not linear
- not associated with proteins/histones
- no introns

Question 6

?

Answer 6

Thicker capsule so phagocytes are less likely to be stimulated by/bind to murein in cell wall
Reduced phagocytosis so more bacterial growth/division/reproduction/binary fission