Transcription Factors

Question 1

Which hormones cannot cross the cell membrane?

Answer 1

Peptide hormones

Question 2

Which hormones are able to cross the cell membrane?

Answer 2

Steroid hormones

Question 3

How do steroid hormones work?

Answer 3

1. Hormone enters cell and binds to receptor
2. This forms hormone-receptor complex
3. This acts as a transcription factor, activating or repressing genes

Question 4

How do peptide hormones work?

Answer 4

1. Hormones bind to receptor on the cell membrane
2. This activates messenger molecules in the cell cytoplasm
3. Messenger molecules activate protein kinases
4. This triggers a cascade inside the cell
5. During the cascade, transcription factors are activated

Question 5

What is a cascade?

Answer 5

A chain of reactions

Question 6

How do transcription factors work?

Answer 6

1. They bind to promoter regions on the DNA strand and increase or decrease the rate of transcription.

Question 7

What is a promoter region?

Answer 7

The section of DNA near the start of the gene that allows it to be transcribed.

Question 8

What are activators?

Answer 8

Transcription factors that increase the rate of transcription

Question 9

What are repressors?

Answer 9

Transcription factors that decrease the rate of transcription