Cell Communication

Question 1

Cell Communication allows for

Answer 1

Allows for cells in a multicellular organism (and unicellular organisms) to coordinate their activities

Question 2

Cells communicate with each other via

Answer 2

chemical signals

Question 3

Unicellular organisms in tough conditions
Example?

Answer 3

Can use cell communication to come together and form multicellular organism (fruiting bodies)

Question 4

Why is cell communication important in organisms like Sacharomyces cervisae (Brewers yeast)

Answer 4

Because there are 2 sexes. a and alpha.
They use chemical messengers to identify members of the opposite sex.

Each has receptors for the opposite sex’s’ messengers

Question 5

Chemical messenger

Answer 5

Aka Ligand
Biomolecule that acts as a message/does the signaling

Question 6

Receptor

Answer 6

Protein
Binds with a specific Ligand/Chemical Messenger

Question 7

A cell can only respond to a messenger

Answer 7

If it has the matching receptor

Question 8

2 ways of direct contact cell communication

Answer 8

Cell Junctions
Cell to cell recognition

Question 9

Cell junction(2 kinds)

Answer 9

Plasmodesmata in plants
Gap junctions in animals

Question 10

Cell to cell recognition

Answer 10

When the glycoprotein of one cell binds to the receptor of another cell

Question 11

Local signaling 3 steps

Answer 11

1) Secretory cell makes and secretes CM
2) CM diffuses
3) Target cell with the right receptors responds to the CM

Question 12

Paracrine signaling

Answer 12

When the target and secretory cell are in the same area/close proximity

Question 13

Synaptic signaling

Answer 13

Done by neurons
Secretes CM (called a Neurotransmitter) in a local area to a target cell

Question 14

Distance signalling

Answer 14

Secretory cell= Endocrine cell
Ligand/CM= Horomones
Endocrine cell synthesizes and secretes horomones

Question 15

Horomones travel in ___ signaling via the

They will only bind with

Answer 15

Distance
The bloodstream
Cells with the right receptor (target cells)

Question 16

Is Distance signaling used in plants?

Answer 16

Yes

Question 17

3 phases of cell signaling

Answer 17

Reception
Transduction
Response

Question 18

Reception

Answer 18

Ligand binds to receptor (transmembrane protein)

Question 19

Transduction connects
What initates transduction

Answer 19

Connects reception and cell response
Receptor initiates transduction pathway (molecule relay)

Question 20

Response involves the

Answer 20

Activation of target cell response

Question 21

Tyrosine kinase

Answer 21

1. Ligand binds to receptor.
2. Causes dimerization (2 fusing together).
3. Self phosphorylation occurs (Gets 6 phosphates).
4. Relay protein is activated by the Phosphate.
5. Causes cell response.

Question 22

Tyrosine

Answer 22

Receptor part

Question 23

Kinase-

Answer 23

The enzyme that phosphorylates

Question 24

G protein coupled receptor 6 steps

Answer 24

1.Ligand binds to inactive G protein coupled receptor
2. Receptor is activated. Causes G protein to bind.
3. GDP falls off. Replaced by GTP.
4. Signal molecule is released
5. Cell response activates, GTP goes off to activated enzyme (or sum else)
6. G protein released as GDP+P

Question 25

Ligand gated ion channel

Answer 25

1. Ligand binds 2. Gate opens and diffusion occurs 4. Cell response occurs 3. Ligand leaves and gate closes

Question 26

3 transmembrane receptors

Answer 26

Tyrosine kinase G coupled protein receptor Ligand gated ion channel

Question 27

Transcription factors

Answer 27

Proteins that influence transcription and gene expression

Question 28

In addition to transmembrane receptors there are also How do they work? 5 steps

Answer 28

Intracellular receptors Inactive In cytoplasm (not plasma membrane) Bind with hydrophobic ligands (lipids) Forms hormone receptor complex Causes it to go through nuclear pores Acts on dna (turns genes on/off)

Question 29

Intracellular receptors are also

Answer 29

Transcription factors since they act on rna production

Question 30

Signal transduction converts

Answer 30

Converts signal outside the cell into a form that can bring about a cell response

Question 31

Signal transduction is usually a ___ process that involves one or more of the following

Answer 31

(Multistep) protein phosphorylation/Dephosporylation change in second messenger concentration (small molecules/ions)

Question 32

PP

Answer 32

Phosphitase Takes off a phosphate

Question 33

How does signal transduction use phosphorylation/dephosphorylation

Answer 33

Ligand binds activating relay molecule Which activates Protein kinase Takes second PK and adds Phosphate Activates second PK Same process for third Activates protein+cell response

Question 34

Change in second molecule concentration cAMP

Answer 34

Gprotein activates Enzyme Adenylyl Cylcase Adenylyl Cyclase takes 2 phosphates off ATP Signaling molecule cAMP is made cAMP acts on protein->cell response Enzyme phosphodiasterase turns cAMP into AMP

Question 35

Calcium ion concentration? Due to? Change is second messenger concentration

Answer 35

High Ca+ outside cell, in smooth ER, mito matrix.(Happens due to calcium pumps)

Question 36

IP3 and Calcium are both ____ in the ____

Answer 36

Secondary messengers in the transduction pathway

Question 37

Where does response occur

Answer 37

Can occur in nucleus via control of gene expression(turning on/off)/transcription Can also occur in cytoplasm

Question 38

Apoptosis

Answer 38

Cell death When receptor for death signaling molecule binds with ligand Leads to apoptosis

Question 39

Regulation of response (2 kinds)

Answer 39

1) Signal Amplification (due to enzymes) One receptor can activate many proteins->x100 cAMP 2)Coordination/regulation with other pathways

Question 40

4 ways cell can respond to same signaling molecule

Answer 40

1) pathway lead to a single response 2) pathway branches leading to 2 responses 3) crosstalk occurs between pathways (Another transduction pathway activates/inhibits the first) 4)Different receptor leading to different response

Question 41

How is IP3 produced and What does it do

Answer 41

Gprotein activates phospholipase C which Produces IP3 IP3 binds to gated calcium channels Opens the gate ATP is used to pump calcium and create gradient

Question 42

Cellular Response can occur in the ____ and the _____.

Answer 42

Nucleus and cytoplasm In nucleus cell response controls transcription/gene regulation