Cell Signaling Chp 9-exam 3

Question 1

Cells communicate by using…

Answer 1

Chemical signals that bind to specific receptor

Question 2

Cell signaling consists of 4 elements

Answer 2

Signaling cell, signaling molecule, receptor protein, and responding cell.

Question 3

Signaling cell

Answer 3

Is the source of a signaling molecule

Question 4

Signaling molecule

Answer 4

Vary immensely to include peptides, lipids, and gases. The signaling molecule carries information from one cell to the next.

Question 5

Receptor protein

Answer 5

Where the signaling molecule binds to, either on or in the responding cell.

Question 6

Quorum sensing

Answer 6

A process by which the bacteria are able to determine whether they are at a low or high population density and then turn on specific genes across the entire community

Question 7

Receptor activation

Answer 7

When a signaling molecule binds to a receptor on a responding cell, the first step is receptor activation. On binding the signal, the receptor is turned on, or activated. This happen because there is a conformational change in the receptor.

Question 8

Signal transduction

Answer 8

Once activated, the receptor often triggers a series of downstream events. Can think of as a chain reaction. The signal is often amplified with each step.

Question 9

Cellular response

Answer 9

Can take different forms depending on the nature of the signal and type of responding cell. Eg. turns on genes that cause cell to divide, change shape or signal other cells

Question 10

Termination

Answer 10

The cellular response is stopped. This also protects the cell from overacting to existing signals and therefore helps the cell to have an appropriate level of response.

Question 11

Endocrine signaling

Answer 11

Signaling by means of molecules that travel through the blood stream

Question 12

Paracrine signaling

Answer 12

Signaling that occurs between two cells that are close to each other. They move by diffusion between the two cells.

Question 13

Growth factor

Answer 13

In paracrine signaling, the signal is usually a small, water soluble molecule such as growth factor. Growth factor is a type of signaling molecule that causes responding cell to grow, divide or differentiate. Eg platelets

Question 14

Sonic hedgehog

Answer 14

Type of growth factor that ensure motor neurons in your spinal cord are located properly, that bones in your vertebrae column form correctly, and that your thumb and pinky fingers are on the correct sides of your hands

Question 15

Autocrine signaling

Answer 15

Single molecules released by a cell and then bind to receptors on the very same individual cell. Signaling and responding cell are one and the same

Question 16

Delta

Answer 16

Transmembrane protein that will become neurons. Delta is signaling molecule that binds to notch- the receptor

Question 17

Ligand

Answer 17

Signaling molecule often referred to as ligand

Question 18

Ligand-binding site

Answer 18

The signaling molecule binds to a specific part of the receptor protein called ligand binding site. The bond is non covalent and highly specific. Causes conformational change in the receptor

Question 19

Receptors for polar signaling molecules are on the cell surface

Answer 19

The location of a particular receptor in a cell depends on whether the signaling molecule is polar or non polar.

Question 20

G protein coupled receptor

Answer 20

One type of cell surface receptor, when Ligand binds to a G protein coupled receptor, the receptor couples to or associates with a G protein.

Question 21

Receptor kinases

Answer 21

second group of cell surface receptors are themselves enzymes which are activated when the receptor binds its ligand. A kinase is an enzyme that catalyzes the transfer of a phosphate group from ATP to a substrate. To catalyze this, it binds to both ATP and substrate. This process is called phosphorylation.

Question 22

Phosphatases

Answer 22

Remove a phosphate group in a process called de phosphorylation. Protein then becomes inactive

Question 23

Ion channels

Answer 23

Receptor that alters the flow of ions across the plasma membrane

Question 24

Voltage gated ions

Answer 24

Receptor that opens in response to changes in voltage across the membrane

Question 25

Ligand gated ion channels

Answer 25

Ion channel opens when bound by their ligand

Question 26

Two common characteristics of G coupled receptors?

Answer 26

They have similar structures consisting of single polypeptide chain that has 7 trans membrane spanning regions w/ligand binding site on outside of cell and portion that G binds to on the inside of the cell
2nd, when activated they associate with a G protein so they can transmit the signal from outside to inside the cell.

Question 27

What is the first step in cell signaling?

Answer 27

Receptor activation

Question 28

As long as the G protein is bound to this, it is in the on position?

Answer 28

GTP

Question 29

What are considered first messengers?

Answer 29

Adrenaline and growth factor

Question 30

Second messengers and how they respond

Answer 30

Cyclic AMP
They are signaling molecules found inside the cell that relays information to the next target in the signal transduction pathway.

Question 31

Binding affinity

Answer 31

Most ligand do not bind permanently. The length of time a signaling molecule remains bound to its receptor depends on how tightly the receptor holds on to it.

Question 32

A second place where the signal is terminated?

Answer 32

The G protein itself. G protein catalyze the hydrolysis of GTP to GDP and inorganic phosphate

Question 33

Signaling pathway

Answer 33

Receptor activation, signal transduction, cellular response, and termination

Question 34

Dimerization

Answer 34

The partnering of two similar or identical molecules

Question 35

Mitogen activated protein kinase pathway

Answer 35

MAP kinase pathway is a series of kinases collectively activated