3.8.2.2 - REGULATION OF TRANSCRIPTION AND TRANSLATION

Question 1

one method of transferring RNAi molecules into cells involves combining these molecules with a lipid.

suggest why this increases uptake of RNAi molecules into cells (1)

Answer 1

1. phospholipid bilayer
2. no need for channel/carrier protein for uptake

Question 2

testosterone is a steroid hormone that belongs to a group of male sex hormones called androgens.

steroid hormones are hydrophobic.

explain why steroid hormones can rapidly enter a cell by passing through its cell-surface membrane. (2)

Answer 2

1. lipid soluble
2. can diffuse through phospholipid bilayer

Question 3

testosterone is a steroid hormone that belongs to a group of male sex hormones called androgens.

in the cytoplasm, testosterone binds to a specific androgen receptor (AR). an AR is a protein.

suggest and explain why testosterone binds to a specific AR (2)

Answer 3

1. has a specific tertiary structure
2. structures are complementary

Question 4

testosterone is a steroid hormone that belongs to a group of male sex hormones called androgens.

in the cytoplasm, testosterone binds to a specific androgen receptor (AR). an AR is a protein

the binding of testosterone to an AR changes the shape of the AR.

this AR molecule now enters the nucleus and stimulates gene expression.

suggest how the AR could stimulate gene expression (2)

Answer 4

1. AR is a transcription factor
2. binds to promoter region on DNA
3. stimulates DNA polymerase

Question 5

suggest how transcription factors can reprogramme cells to form iPS cells (2)

Answer 5

1. attach to promoter region
2. inhibit/stimulate transcription/RNA polymerase