1.4 Hydrophobic Signalling

Question 1

What do hydrophobic signaling molecules have the ability to do

Answer 1

Diffuse directly through the phospholipid bilayers of membranes and bind to intracellular receptors

Question 2

What are the receptors in hydrophobic signaling

Answer 2

Transcription factors

Question 3

An example of a hydrophobic signaling molecule

Answer 3

Steroid hormones eg testosterone and oestrogen

Question 4

Define transcription factors

Answer 4

Proteins that when bound to DNA can either stimulate or inhibit initiation of transcription

Question 5

Step 1 hydrophobic: Steroid hormones bind to specific receptors in the

Answer 5

Cytosol or nucleus

Question 6

Step 2 hydrophobic: a hormone receptor complex is formed it moves to the ….

Answer 6

Nucleus

Question 7

Step 2 hydrophobic: once the hormone-receptor complex is in the nucleus it binds to…

Answer 7

Specific sites on DNA and effects gene expression

Question 8

Step 2: hydrophobic the hormone receptor complex binds to specific DNA sequences called

Answer 8

Hormone response elements (HRE)

Question 9

Step 2 hydrophobic: binding at HREs influences….

Answer 9

The rate of transcription
Each steroid hormone affects the gene expression of many different genes

Question 10

Explain fully the events of hydrophobic signaling

Answer 10

Hydrophobic signaling molecules can diffuse directly through the phospholipid bilayers of membranes and bind to intracellular receptors.
These receptors are transcription factors.
Transcription factors are proteins , that when bound to DNA can either stimulate or inhibit the initiation of transcription
The steroid hormones , oestrogen and testosterone are examples of hydrophobic signaling molecules
Steroid hormones bind to specific receptors in the cytosol or nucleus
The hormone receptor complex is formed, and moves to the nucleus where it binds to specific DNA sequences (hormone response elements) and influences the rate of transcriptionwith each steroid hormone affecting the gene expression of many genes