Chapter 11: Cell Communication

Question 1

What are cell signaling mechanisms an example of?

Answer 1

Evolutionary Relatedness!

Question 2

What is the connection used in animal cells?

Answer 2

Gap Junctions

Question 3

What is the connection used in plant cells?

Answer 3

Plasmodesmata

Question 4

Paracrine Signaling

Answer 4

Signaling cell secretes signaling molecule that only travels a short distance

Question 5

Synaptic Signaling

Answer 5

secretion of neurotransmitters from a neuron that triggers a response in target cells

Question 6

Endocrine Signaling

Answer 6

hormones are secreted and travel throughout the body via the bloodstream.

Question 7

Three Stages of Cellular Signaling

Answer 7

Reception, Transduction, Response

Question 8

What do “Signal Transduction Pathways” do?

Answer 8

They convert a signal originating outside the cell into a cellular response

Question 9

What is “reception”?

Answer 9

A signaling molecule bins to a receptor protein, causing it to change shape

Question 10

What are Ligands?

Answer 10

signaling molecules that bind to another, often larger molecules

Question 11

what does binding of a ligand do?

Answer 11

causes a change in shape, meaning a change in function too….because structure determines function!

Question 12

Why is reception specific?

Answer 12

Because cells only respond to signals for which they have a specific receptor for.

Question 13

Ligands have a high…

Answer 13

degree of specificity

Question 14

3 main receptors in plasma membranes

Answer 14

1.) G-protein coupled receptor (GPCR)
2.) Receptor Tyrosine Kinase (RTK)
3.) Ligand Gated Ion Channels (LGIC)

Question 15

When is the GPCR active?

Answer 15

When bound to GTP

Question 16

What does GTPase do?

Answer 16

hydrolyze GTP to GDP + Pi = inactive

Question 16

When is the GPCR inactive?

Answer 16

When bound to GDP

Question 17

What is RTK involved in?

Answer 17

controlling cell division!

Question 18

What is dimerization?

Answer 18

when ligands bind to 2-receptor monomers, the RTK forms a dimer

Question 19

What is transduction?

Answer 19

cascades of molecular interactions relay signals from receptor to target molecules in the cell

Question 20

NOTE***

Answer 20

The original signaling molecule is not passed along, only the information it carries is!

Question 21

Signal Amplification

Answer 21

benefit of transduction

Question 22

What molecule carries out protein phosphorylation?

Answer 22

Protein Kinases

Question 23

What molecule carries out protein de-phosphorylation?

Answer 23

Protein Phosphhotases

Question 24

What are common second messangers?

Answer 24

Cyclic AMP, Calcium ions

Question 25

What does the addition of the phosphate do?

Answer 25

Activation!

Question 26

What are second messangers?

Answer 26

small, non protein molecules that spread rapidly throughout a cell by diffusion or laterally in a membrane

Question 27

what does cAMP stand for?

Answer 27

cyclic adenosine monophosphate

Question 28

what does IP3 stand for?

Answer 28

inositol triphosphate

Question 29

what converts ATP into cAMP?

Answer 29

Adenylyl Cyclase

Question 30

What converts cAMP back into ATP?

Answer 30

Phosphodiesterase

Question 31

Where are the calcium ions stored?

Answer 31

Endoplasmic Reticulum

Question 32

what does DAG stand for?

Answer 32

diacylglycerol

Question 33

how are IP3 and DAG produced?

Answer 33

they are produced by clevage of specific type of phospholipid called PIP3 in the plasma membrane

Question 34

What the two main cellular responses?

Answer 34

Cytoplasmic and Nuclear

Question 35

What do nuclear pathways do?

Answer 35

aid in gene regulation by changing the shape of the proteins made, therefore changing the function

Question 36

What is the degree of response regulated by? 4 things.

Answer 36

1.) Signal Amplification 2.) Coordination of Response 3.) Signal Efficiency 4.) Termination of Signal

Question 37

What is signal amplification?

Answer 37

the process by which the activated products can be much greater in number than the preceeding step.

Question 38

How is signal amplification performed?

Answer 38

Protein Catalysts (Enzymes)

Question 39

What are the four different signal pathways a signal can take?

Answer 39

1.) Single Response 2.) Two Responses 3.) Cross Talk 4.) Different Response

Question 40

How do Kinases' find substrate so quickly?

Answer 40

Scaffolding Proteins

Question 41

What do scaffolding proteins do?

Answer 41

hold proteins in a pathway together and relay large proteins in order to increase transduction efficiency

Question 42

What are the 4 inactivation mechanisms?

Answer 42

1.) Reverse Ligand Binding 2.) GTPase hydrolysis of GTP 3.) Dephosphorylation via Phosphotases 4.) cAMP hydrolysis by phosphodiesterase