june 2017- paper 1 Flashcards
1
Q
describe the structure of glycogen (2)
A
large polymer of a-glucose joined together by glycosidic bonds
2
Q
co-transport (3)
A
- hydrolysis of atp used
- substances bind to the protein
- protein changes shape
3
Q
why does high absorption of salt lead to more tissue fluid (2)
A
- lower water potential of tissue fluid
- less water returns to capillary by osmosis
4
Q
why do some bacteria excrete extracellular enzymes (2)
A
- to digest protein
- so the amino acids can be absorbed
5
Q
how does phagocytosis lead to expression of antigens? (3)
A
- phagosome fuses with lysosome
- virus destroyed by lysosymes
- antigens are displayed on the cell membrane
6
Q
how does presentation of an antigen lead to the secretion of an antibody? (4)
A
- TH cell binds to the antigen
- stimulates a B cell
- B cell clones
- produces plasma cells
7
Q
3 comparisons of genetic diversity
A
- mRNA base sequence
- amino acid sequence
- DNA sequence
8
Q
6 ways an insect’s tracheal system is adapted for efficient gas exchange
A
- tracheoles have thin walls so short diffusion distance
- highly branched so short diffusion distance
- highly branched so large surface area
- tracheae are tubes of air so fast diffusion
- fluid in the end of tracheoles that moves out during exercise so faster diffusion
- body can be moved to maintain concentration gradient