Chapter 11

Question 1

A series of steps linking a mechanical or chemical stimulus to a specific cellular response.

Answer 1

Signal Transduction Pathway

Question 2

A secreted molecule that influences cells near where it is secreted.

Answer 2

Local Regulators

Question 3

An enzyme that converts ATP to cyclic AMP in response to a signal.

Answer 3

Adenylyl Cyclase

Question 4

A program of controlled cell suicide, which is brought about by signals that trigger the activation of a cascade of suicide proteins in the cell destined to die.

Answer 4

Apoptosis

Question 5

Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons.

Answer 5

Cyclic AMP (cAMP)

Question 6

A small, nonprotein, water-soluble molecule or ion, such as a calcium ion (Ca2+) or cyclic AMP that relays a signal to a cell’s interior in response to a signaling molecule bound by a signal receptor protein.

Answer 6

Second Messenger

Question 7

A second messenger produced by the cleavage of a certain kind of phospholipid in the plasma membrane.

Answer 7

Diacylglycerol (DAG)

Question 8

A GTP binding protein that relays signals from a plasma membrane signal receptor, known as a G protein-coupled receptor, to other signal transduction proteins inside the cell.

Answer 8

G protein

Question 9

A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by activating a G protein. Also called a G protein-linked receptor.

Answer 9

G Protein-Coupled Receptor

Question 10

In multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body to change their functioning.

Answer 10

Hormone

Question 11

A molecule that binds specifically to another molecule, usually a larger one.

Answer 11

Ligand

Question 12

A protein pore in cellular membranes that opens or closes in response to a signaling chemical (its ligand), allowing or blocking the flow of specific ions.

Answer 12

Ligand-Gated Ion Channel

Question 13

A second messenger that functions as an intermediate between certain nonsteroid hormones and a third messenger, a rise in cytoplasmic Ca2+ concentration.

Answer 13

Inositol triphosphate (IP3)

Question 14

An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.

Answer 14

Protein Kinase

Question 15

An enzyme that removes the phosphate groups from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase.

Answer 15

Protein Phosphatase

Question 16

In cellular communication, the change in a specific cellular activity brought about by a transduced signal from outside the cell.

Answer 16

Response

Question 17

The target cell’s detection of a signaling molecule coming from outside the cell. A chemical signal is “detected” when the signaling molecule binds to a receptor protein located at the cell’s surface or inside the cell.

Answer 17

Reception

Question 18

A receptor protein in the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a phosphate group from ATP to a tyrosine on another protein. They often respond to the binding of a signaling molecule by dimerizing and then phosphorylating a tyrosine on the cytoplasmiic portion of the other receptor in the dimer. The phosphorylated tyrosines on the receptors then activate other signal transduction proteins within the cell.

Answer 18

Receptor Tyrosine Kinase

Question 19

A type of large relay protein to which several other relay proteins are simultaneously attached, increasing the efficiency of signal transduction.

Answer 19

Scaffolding Protein

Question 20

In cellular communication, the conversion of a signal from outside the cell to a form that can bring about a specific cellular response.

Answer 20

Transduction