L49 Regulation of Cells

Question 1

How is formation of pancreatic juice initiated?

Answer 1

1) Secretin produced in small intestine in response to HCl from stomach
2) Secretin carried in blood
3) Secretin reaches pancreas and stimulates cells to secrete pancreatic juice.

Question 2

What is rhodopsin signalling?

Answer 2

Rhodopsin is a light-sensitive chemical found in rods of retina. The physical stimulus (light) is converted to chemical (rhodopsin).

Question 3

What are the 2 main second messengers?

Answer 3

cAMP and Ca2+

Question 4

How does cholera cause diarrhoea?

Answer 4

Toxin produced by bacteria enters cells in gut, binds covalently to G protein, constantly causes activation of adenylyl cyclase.

This increases sodium and water in the gut lumen.

Question 5

Somatostatin is an example of __?__ signalling.

Answer 5

paracrine

Acts on neighbouring pancreatic cells to inhibit insulin secretion.

Question 6

Insulin-like growth factor (IGF) is an example of __?__ signalling.

Answer 6

autocrine

Question 7

True or false: In intracrine communication, the signalling molecules never leave the cell.

Answer 7

True.

This type of communication is between different parts of the same cell (e.g. nucleus and organelles).

Question 8

A steroid receptor inside a cell has 3 functional domains. What are they?

Answer 8

• Hormone-binding domain (HBD)
• DNA-binding domain (DBD)
• domain that interacts with coactivators to affect gene expression

Question 9

Mitogen-activated protein (MAP) kinases are activated by __?__

Answer 9

kinase cascades - initiated by type 3 receptors