Cell Signaling Flashcards

1
Q

What do multicellular organisms require in order to function?

A

precise internal communication

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2
Q

exes of precise internal communication

A

o Example- animals have nervous systems in which neuronstransmit information electrically and chemically o Plants and animals have hormones as signals between cells andorgans

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3
Q

Signal transduction

A

the process by which cells convert and amplify an extra-cellular signal into an intra-cellular signal

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4
Q

Ligands

A

signaling molecules/first messenger

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5
Q

Examples of signaling molecules:

A

Neurotransmitters (produced by nerve cells) Hormones

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6
Q

First step of signaling

A

1- Synthesis and release of the signaling molecules

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7
Q

Second step of signaling

A

2- Transport to target cells

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8
Q

Third step of signaling

A

3- Reception of the information by target cells

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9
Q

Fourth step of signaling

A

4- Signal transduction

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10
Q

Fifth step of signaling

A

5- Response by the cell

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11
Q

Sixth step of signaling

A

6- Termination of signaling

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12
Q

Examples of cell signaling in unicellular bacteria, protists, fungi–amoeba

A

Amoeba-like cellular slime mold secretes cAMP (cyclic adenosine monophosphate) when food is scarce, causing other slime molds to come together and form amulticellular slug-shaped colony

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13
Q

Examples of cell signaling in unicellular bacteria, protists, fungi–yeast

A

Yeast cells send out signals to mate with one another

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14
Q

Examples of cell signaling in unicellular bacteria, protists, fungi–sperm

A

Sperm have receptors that respond to chemical signalsthat guide the sperm to the egg

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15
Q
  • Response by the cell– The activated enzyme can either
A
  1. Catalyze the production of large numbers of intracellular signaling molecules, called second messengers2. Or it may activate intracellular enzymes called protein kinases
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16
Q

protein kinases

A

enzymes that activate specific proteins by transferring phosphate groups to them from ATP

17
Q

second messengers, like___

A

cAMP (catalyzed by enzyme called adenylyl cyclase)

18
Q

Cell signaling

A

mechanism by which cells communicate with each other. One cell secretes ligand, which combines with receptors on a diff cell

19
Q

What synthesizes ligands?

A

Either synthesized by neighboring tissue or by

specialized tissue that may be far away

20
Q

Transport of ligands

A

by diffusion or via the circulatory system

21
Q

Reception of the information by target cells

A

Ligands bind to

receptors on target cells

22
Q

How can regulatory molecules transmit information to the cell without physically crossing the plasma membrane?

A

by using systems of interacting integral membrane proteins–Each component in signal transduction acts as a “switch”-activated or inactivated

23
Q

Receptor

A

transmembrane protein with 3

domains

24
Q

3 domains of receptor

A

One on extracellular surface, acts as docking site for ligand
Second extending through plasma membrane
Third is “tail” that extends into cytoplasm

25
When ligand, or first messenger, binds to receptor, how does it activate it?
by changing the | shape of the receptor tail that extends into the cytoplasm
26
What does the activated receptor do?
changes the conformation of a second protein, sometimes called G protein, which then becomes activated. GTP then turns into GDP, which releases energy.
27
Why is 2nd protein called a G protein?
Called G protein because when it’s in activated form, it is bound to guanosine triphosphate (GTP- similar to adenine).
28
What happens after the activated receptor changes the conformation?
Eventually, this causes | activation of a specific enzyme bound to the membrane