Transcription factor & RNAi

Question 1

Transcription factors

Answer 1

• proteins that bind to DNA
• move from cytoplasm to DNA when activated
• binds to complementary bases
• initiates transcription

Question 2

Oestrogen

Answer 2

• steroid hormone that initiates transcription
• lipid soluble so diffuses into cells- in cytoplasm
• binds to receptor on transcription factor
• causes TF to change shape slightly making it complementary to DNA and able to initiate transcription

Question 3

RNAi

Answer 3

• mRNA that has been transcribed gets destroyed before it is translated to create a polypeptide chain
• done by a small interfering RNA (siRNA)

Question 4

steps

Answer 4

• enzyme cut mRNA into siRNA
• 1 strand combines with another enzyme
• siRNA-enzyme complex binds via base pairing to another mRNA
• once bound enzyme cuts mRNA so it can’t be translated