Diversity of Cell Surface Receptors

Question 1

What steps are involved in the action of extracellular messengers on target cells?

Answer 1

1. Interaction with a receptor to form a receptor-ligand complex
2. Activation of the receptor
3. Transduction of a signal to intracellular effectors

Question 2

What are the TWO changes which occur in cells as a result of an initial signalling?

Answer 2

1. Change in metabolism
2. Change in intracellular ion concentration

Question 4

What are the TWO types of cell surface receptors?

Answer 4

1. Metabotropic
2. Ionotropic

Question 5

What is Signal Amplification?

Answer 5

One extracellular messenger molecule can activate, or lead to the generation of, many intracellular response molecules

Question 6

Do a small or large amount of extracellular signalling molecules binding to a small number of high affinity receptor proteins elicit a full cellular response?

Answer 6

Small amount

Question 7

What is the mechanism of transcription factor (TF) for Receptor Tyrosine Kinases (RTKs)?

Answer 7

Phosphorylation by cytosolic kinase in nucleus or cytosol

Question 8

What is the mechanism of transcription factor (TF) activation for G Protein-Coupled Receptors (GPCRs)?

Answer 8

Phosphorylation in nucleus by Protein Kinase A

Question 9

What are the SEVEN requirements for a signalling molecule?

Answer 9

1. Synthesis
2. Secretion by signalling cell
3. Transport to target cell
4. Binds to and activates specific receptor
5. Initiates intracellular signal transduction pathway
6. Induces changes in cellular function or metabolism
7. Removed / eliminated after functioning

Question 10

TRUE OR FALSE:
Some signalling molecules can stimulate BOTH secondary messenger activation and ion channel opening

Answer 10

True

Question 11

What are the TWO types of Acetylcholine receptor?

Answer 11

1. Nicotinic
2. Muscarinic

Question 12

What class of receptor is a Nicotinic Receptor based on structure?

Answer 12

Multi-subunit receptor

Question 13

What class of receptor is a GPCR based on structure?

Answer 13

7-transmembrane spanning receptor

Question 14

What class of receptor is an Epidermal Growth Factor (EGF) Receptor based on structure?

Answer 14

Single transmembrane spanning receptor

Question 15

What are the functions of the two types of chain in an Insulin Receptor?

Answer 15

• α chains bind ligand
• β chains transmit the signal into the cell