Topic 8 - 7 - Regulation of Transcription and Translation (Incomplete - RNAi)

Question 1

What is a transcription factor?

Answer 1

A protein molecule that controls the transcription of a gene

Question 2

What is a promoter region?

Answer 2

A DNA sequence that tells the enzyme RNA polymerase where to start producing mRNA

Question 3

What is an activator?

Answer 3

A transcription factor that increases the rate of transcription

Question 4

What is a repressor?

Answer 4

A transcription factor that inhibits or decreases the rate of transcription

Question 5

How does oestrogen affect transcription?

Answer 5

Oestrogen binds to an oestrogen receptor (a type of transcription factor), which forms an oestrogen-oestrogen receptor complex. This then moves from the cytoplasm to the nucleus where it binds to specific DNA sites near the start of the target gene. It then acts as an activator of transcription

Question 6

What is RNAi?

Answer 6

RNA interference - The mechanism by which siRNA or mRNA affects translation

Question 7

Summarise how RNAi works

Answer 7

• mRNA leaves the nucleus after transcription
• ## siRNA associates with proteins in the cytoplasm