Unit 4: Cell Communication and Cell Cycle

Question 1

Direct signalling

Answer 1

signalling where cells are making physical contact with each other

Question 2

Juxtacrine signalling

Answer 2

Signal is transmitted with direct contact between cells

Question 3

Autocrine signalling

Answer 3

Cell makes and receives own signal

Question 4

Local/Paracrine signalling

Answer 4

ligand (signalling molecule) is released into the environment and is received by nearby cells

Question 5

Endocrine signalling

Answer 5

signal travels through the bloodstream

Question 6

What is a ligand?

Answer 6

-signaling molecules
-actives pathway by binding to receptor

Question 7

Extracellular

Answer 7

Ligand binds to receptor outside the cells
-polar
ex.) protein

Question 8

Intracellular

Answer 8

Ligand binds to receptors inside the cell
-nonpolar
ex.) hormones

Question 9

What is the first step of a signal transduction pathway?

Answer 9

Reception
-ligand must bind to the receptor
-specific shape change will occur
-signal goes to next step

Question 10

What is the second step of a signal transduction pathway?

Answer 10

Transduction
-signal is relayed or modified or amplified
-Phosphorylation cascade can occur here

Question 11

What is the third step of a signal transduction pathway?

Answer 11

Response
-goal of the pathway
-cells begin to take action

Question 12

What is the purpose of interphase?

Answer 12

Prepares cells for division by creating more cellular components

Question 13

List each step of interphase

Answer 13

1. G0 normal cell function
2. G1 cell growth
3. S DNA replication
4. G2 Cell growth
5. M cell division mitosis or meiosis

Question 14

Where are the checkpoints in interphase?

Answer 14

1. G1 checks for damaged cells and makes sures the cells are functioning properly
   2.) G2 makes sure DNA is properly replicated
   3.) Metaphase ensures spindle fibers are properly connected