Lecture 11 Study Guide

Question 1

How do cell junctions facilitate communication between cells? Do the cells need to be touching each other?

Answer 1

the connect the cytoplasms of adjacent cells to communicate

Question 2

Outline two examples of local signaling. Which involves a synaptic cleft?

Answer 2

paracrine signaling and synaptic signaling; synaptic signaling

Question 3

Stages of cell signaling

Answer 3

1. reception
2. transduction
3. response

Question 4

What is GTP?

Answer 4

a molecule used by a G-protein to activate a third protein that elicits a cellular response

Question 5

Outline the activity of a kinase enzyme.

Answer 5

kinase enzymes phosphorylate

Question 6

RTKs can initiate several transduction pathways upon activation. How does this differ from GPCRs?

Answer 6

GPCRs activate only one transduction pathway

Question 7

How are RTK receptors closely associated with the development of cancer?

Answer 7

RTK receptors coordinate cell growth and reproduction

Question 8

List 4 types of ion channels.

Answer 8

1. ligand gated ion channels
2. voltage gated ion channels
3. mechanical gated ion channels
4. light-gated ion channels

Question 9

Distinguish between peptide vs steroid long distance signals. Which requires a cell surface receptor and why?

Answer 9

peptide hormone: water soluble, receptor in plasma membrane
steroid hormone: lipid soluble, receptor inside cell nucleus

peptide

Question 10

Outline the action of the ligand on the receptor and the flow of ions.

Answer 10

the ligand binds to the receptor so the ions can flow through the channels

Question 11

Name the enzymes responsible for the addition of a phosphate group to a protein and for the hydrolysis of a phosphate group from a protein.

Answer 11

protein kinase

Question 12

Distinguish a primary messenger from a secondary messenger in the transduction process.

Answer 12

primary messengers are ligands and secondary messengers are small non-protein molecules

Question 13

State two common secondary messengers. How can they amplify the transduction of the cellular signal?

Answer 13

cyclic AMP and calcium ions; they are small and water soluble so they can readily diffuse throughout the cell

Question 14

Response: Outline three specific cell responses to a signal.

Answer 14

Three types: change in membrane potential, change in gene expression,change in metabolism;