L15-16 Signalling Through Cell Surface Receptors

Question 1

Cell surface receptors you need to know about (2)…

Answer 1

• Ion channel coupled
• G-Protein linked

(There are enzyme linked cell surface receptors too, but these weren’t covered in the lecture)

Question 2

G-Protein linked cell surface receptors are the largest…

Answer 2

Family of receptors, with over 800 different types found in vision, smell, neurotransmission etc.

Question 3

G-Proteins convert signals form one type to another. They are…

Answer 3

Transducers

Question 4

There are 2 types of G-Protein…

Answer 4

Monomeric and Trimeric G-Proteins

Question 5

G proteins are known as ‘G’ proteins because they interact with…

Answer 5

GDP and GTP molecules

Question 6

Trimeric G-Proteins have 3 subunits…

Answer 6

1. Alpha (binds GDP/GTP)
2. Beta
3. Gamma

Question 7

The two key trimeric G-Proteins are…

Answer 7

1. Adenylyl Cyclase

2. Phospholipase C

Question 8

cAMP activates the…

Answer 8

cAMP dependent protein kinase A (PKA)

Question 9

When cAMP binds to the inactive PKA, there is a…

Answer 9

Conformational change

Question 10

The result of cAMP binding to PKA is two active catalytic subunits and…

Answer 10

Complex of cyclic AMP and 2 regulatory subunits

Question 11

Active catalytic subunits of PKA pass on information by…

Answer 11

Phosphorylating proteins (switching them ‘on’ or ‘off’)

Question 12

The 3 roles of ATP & GTP…

Answer 12

1. RNA synthesis
2. Signal transduction
   2a) cAMP & phosphorylation (ATP)
   2b) cGMP & G-Protein activation (GTP)
3. Carrying energy

Question 13

Glucose release in the fight-or-flight response is an example of a…

Answer 13

Phosphorylation cascade