Chapter 11 - Cell Communication

Question 1

Hormone

Answer 1

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 organism, changing the target’s cells’ functioning

Question 2

Reception

Answer 2

in cellular communication, the first step of a signaling pathway in which a signaling molecule is detected by a receptor molecule on or in the cell

Question 3

Transduction

Answer 3

in cellular communication, the conversion of a signal form outside the cell to a form that can bring about a specific cellular response; also called signal transduction

Question 4

Signal Transduction Pathway

Answer 4

a series of steps linking mechanical, chemical, or electrical stimulus to a specific cellular response

Question 5

Response

Answer 5

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

Question 6

G Protein-Coupled Receptor (GPCR)

Answer 6

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

Question 7

G Protein

Answer 7

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

Question 8

Receptor Tyrosine Kinase (RTK)

Answer 8

a receptor protein spanning 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; often responds to the binding of a signaling molecule by dimerizing and then phosphorylating a tyrosine on the cytoplasmic portion of the other receptor in the dimer

Question 9

Ligand-Gated Ion Channel

Answer 9

a transmembrane protein containing a pore that opens or closes as it changes shape in response to a signaling molecule (ligand), allowing or blocking the flow of specific ions; also called an ionotropic receptor

Question 10

Protein Kinase

Answer 10

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

Question 11

Phosphorylation Cascade

Answer 11

a series of protein phosphorylation occurring sequentially in which each protein kinase phosphorylates the next, activating it; often found in signaling pathways

Question 12

Protein Phosphatase

Answer 12

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

Question 13

Second Messenger

Answer 13

a small, nonprotein, water-soluble molecule or ion, such as a calcium ion (Ca^2+) or cyclic AMP, that relays a signal to a cell’s interior in response to a signaling molecule bound by a signal receptor protein

Question 14

Cyclic AMP (cAMP)

Answer 14

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

Question 15

Adenylyl Cyclase

Answer 15

an enzyme that converts ATP to cyclic AMP in response to an extracellular signal

Question 16

Inositol Triphosphate (IP3)

Answer 16

a second messenger that functions as an intermediate between certain signaling molecules and a subsequent second messenger Ca^2+, by causing a rise in cytoplasmic Ca^2+ concentration

Question 17

Diacylglycerol (DAG)

Answer 17

a second messenger produced by the cleavage of a phospholipid PIP2 in the plasma membrane

Question 18

Scaffolding Proteins

Answer 18

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

Question 19

Apoptosis

Answer 19

a type of programmed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell