Unit 4a - Cell Communication

Question 1

Autocrine Signaling

Answer 1

Cell signals itself

Question 2

Juxtacrine Signaling

Answer 2

Two cells are in contact w/ one another

Question 3

Paracrine Signaling

Answer 3

Two cells that are close but not touching

Question 4

Endocrine Signaling

Answer 4

When ligands travel long distances to signal

Question 5

What are the 3 steps of cellular signaling

Answer 5

Reception
Transduction
Response

Question 6

Reception

Answer 6

Detection of a ligand coming from outside the cell

Question 7

Transduction

Answer 7

Converting a signal to a form that can bring about a response

Question 8

Response

Answer 8

Cellular response to the signal molecule

Question 9

Ligand

Answer 9

Signaling molecule that binds w/ a receptor.

Question 10

What are the two types of receptors

Answer 10

Plasma Membrane
Intracellular

Question 11

What happens in the FIRST step of a G-protein Receptor reaction?

Answer 11

The G protein has an inactive GDP.

Question 12

What happens in the SECOND step of a G-protein Receptor reaction?

Answer 12

The ligand bonds to the receptor and the protein bonds to the receptors. The protein exchanges a GDP for a GTP.

Question 13

What happens in the THIRD and FOURTH steps of a G-protein Receptor reaction?

Answer 13

The ligand unbinds w/ the receptor ; the protein (w/ GTP) binds with an enzyme and a cellular response occurs ; the GTP is turned to a GDP.

Question 14

What happens in the FIRST step of a Tyrosine Kinase Receptor reaction?

Answer 14

A ligand is introduced near the inactive receptor.

Question 15

What happens in the SECOND step of a Tyrosine Kinase Receptor reaction?

Answer 15

Ligands bind w/ the tyrosine kinase –> A dimer is created when the two kinase bind together.

Question 16

What happens in the THIRD step of a Tyrosine Kinase Receptor reaction?

Answer 16

Six ATP give up one phosphate to the 6 tyrosine molecules on the kinase , becoming ADP.

Question 17

What happens in the FOURTH step of a Tyrosine Kinase Receptor reaction?

Answer 17

Multiple cellular responses occur.

Question 18

What happens in the FIRST step of Ligand Gated Ion Channel?

Answer 18

The receptor is closed w/o an ligand to bind and open it.

Question 19

What happens in the SECOND and THIRD steps of a Ligand Gated Ion Channel?

Answer 19

The ligand binds to the receptor and the gate opens –> a cellular response occurs –> ligand detaches and the gate closes.

Question 20

What is the structure of the G-Protein Coupled Receptor?

Answer 20

7 transmembrane segments.

Question 21

Cascades

Answer 21

Relay signals from receptor to target molecule.

Question 22

What is the structure of the Ligand Gated Ion Channel Receptor?

Answer 22

Signal on receptor changes shape ( to regulate the flow of specific ions)

Question 23

Protein Kinase

Answer 23

Enzyme that phosphorylates and activates proteins at the next level.

Question 24

Phosphorylation Cascade

Answer 24

Enhance and amplify signals

Question 25

Second Messenger

Answer 25

Small , non-protein molecules/ions that can relay signal inside the cell.

Question 26

What are the types of Transduction?

Answer 26

Cascades
Protein Kinase
Phosphorylation Cascade
Second Messengers

Question 27

Apoptosis is in what step of Cellular Signaling?

Answer 27

Response

Question 28

What is Apoptosis?

Answer 28

Cell Suicide
- cell is dismantled and digested
- triggered b signals that activated a cascade of “suicide” proteins

Question 29

Why to cells do Apoptosis?

Answer 29

• Protect neighboring cells from damage
• Animal development and maintenance.