Cell Communication

Question 1

Cell Signaling Process

Answer 1

Signal binds to receptor
Signal is transmitted to the interior of the cell by a transduction pathway
Cell responds ex. turning on a gene
Response is terminated so new signals can be received

Question 2

Endocrine

Answer 2

Signaling over long-distances, such as through the bloodstream

Question 3

Paracrine

Answer 3

Signaling through cells that are close together, within 20 cell diameters. This signal is specifically growth factors.

Question 4

Autocrine

Answer 4

Cell signals itself

Question 5

Close-contact (Juxtacrine)

Answer 5

Cells are touching one another, a bridge extended between the two

Question 6

Ligand

Answer 6

Signaling molecule

Question 7

Ligand-binding site

Answer 7

Location on the receptor to which the ligand binds

Question 8

Intracellular receptors

Answer 8

Internal receptors somewhere in the cell, small, nonpolar molecules can pass through the plasma membrane to receptors in the cytoplasm. Usually hormones, which are steroids.

Question 9

Cell-surface receptor

Answer 9

Polar signaling molecules cannot pass the plasma membrane and rely on receptors on the surface

Question 10

Cytoplasmic domain

Answer 10

The part of the receptor in the cytoplasm

Question 11

Extracellular domain

Answer 11

The part of the receptor that is extracellular

Question 12

Transmembrane domain

Answer 12

The part of the receptor located within the plasma membrane

Question 13

G-coupled Protein

Answer 13

Changes conformational shape upon contact with signaling molecule which activates the G-protein. Associated with Adrenaline.

Question 14

Receptor Tyrosine Kinase

Answer 14

Dimerizes upon contact with signaling molecule. Associated with Insulin.

Question 15

Kinase

Answer 15

An enzyme that adds phosphate groups to things (proteins)

Question 16

Phosphorylation

Answer 16

The process of adding a phosphate group to something (a protein/enzyme)

Question 17

Ligand-gated Ion channels

Answer 17

Ligand binds to receptor, which causes the protein to open and allow ions, such as sodium and calcium, through

Question 18

Voltage-gated ion Channels

Answer 18

Ion channels that are triggered by a difference in charge

Question 19

G-Coupled Protein Structure

Answer 19

Contains the alpha, beta, and gamma subunits. The alpha subunit will be bound to either GDP or GTP depending on whether it is active or inactive.

Question 20

G-Coupled Protein Activation

Answer 20

Ligand binds and activates receptor. When receptor is activated, GDP is replaced with GTP, which causes the alpha subunit to separate from the beta and gamma subunit. Activated a subunit binds to and activates target protein.

Question 21

Second Messenger

Answer 21

Intracellular signaling molecules released by the cell in response to extracellular signaling molecules, the first messenger

Question 22

Deactivation of G-coupled Protein

Answer 22

Ligand detaches from receptor, G-protein converts GTP back to GDP, enzymes in the cytosol degrade cAMP (second messengers), phosphotases inactivates proteins, terminates response

Question 23

Nancy Kohler and Lipton

Answer 23

Identified the first growth factor and determined that it was platelets that secreted it, plasma causes growth and serum causes massive growth.

Question 24

Receptor-Mediated Endocytosis

Answer 24

Ligand attaches to receptor
Membrane folds inward
Formation of a coated vesicle
Vesicle fuses with an endosome
Receptors go to cell membrane, and molecules go to lysosome

Question 25

Phosphotases

Answer 25

An enzyme that removes phosphate groups from proteins

Question 25

Amplification

Answer 25

The idea that one activated protein can activate many other proteins, which causes amplification of the signal.

Question 26

Signal Cascade/Transduction pathway

Answer 26

A phosphate group is passed from one kinase to another causing a pathway that eventually leads to a response.

Question 27

Downregulation

Answer 27

Protein degradation: proteins are tagged with Ubiquitin for degradation
Destruction/Alteration of signalling compound
Decreases in concentration of signaling ligand

Question 28

Receptor Tyrosine Kinase Activation

Answer 28

Ligand attaches and dimerizes receptor. Each member of the receptor pair phosphorylates the other, whcih comes from turning ATP into ADP. These phosphate groups provide binding sites for intracellular proteins.

Question 29

MAP Proteins

Answer 29

Hybrid of RTK and G-coupled. Mitogen Activated Proteins. Associated with growth factors. Has an RTK receptor with a G-protein that does GDP to GTP. This is called a Ras protein. Associated with wound healing.

Question 30

Ras Protein Mutations

Answer 30

G-protein equivalents. Mutations in this protein cause cancer. Ras mutations lead to 30% of all human cancers. Some cancers prevent Ras from converting GTP to GDP causing the process to always be on.

Question 31

What cell Signaling issues cause cancer?

Answer 31

Overproduction of receptors leading to an altered response, overproduction of an altered signaling molecule, Ras protein mutations.

Question 32

Phosphodiesterase

Answer 32

Regulate intercellular levels of cAMP and similar second messengers