Deck 20: Mechanisms of Signal Transduction

Question 1

Hormone action is ultimately controlled by the cells that secrete the hormone.

Answer 1

False

Question 2

The protein products of viral ________ are often components of signal transduction pathways that result in tumorigenesis.

Answer 2

oncogenes

Question 3

Steroid hormones are cytosolic ligands for a class of nuclear receptors that exert their effects by binding to specific sites on ________.

Answer 3

DNA

Question 4

G proteins are membrane-bound proteins that bind GDP when inactive.

Question 5

The end result of a signal transduction pathway is often a change in gene expression.

Question 6

Most synaptic transmission events are mediated electrically through gap junctions between cells.

Question 7

Nuclear receptors:

A) reside on the nuclear membrane.
B) do not bind to hormones.
C) reside only within the nucleus of a cell.
D) are DNA rather than proteins.
E) are transcriptional regulators.

Question 8

The membrane-bound receptor in G protein-coupled signal transduction is quite separate to the effector enzyme which catalyses the formation of an intracellular ________.

Question 9

Which of the following does NOT belong to a receptor tyrosine kinase family?

A) Platelet-derived growth factor receptor
B) Insulin receptor
C) Fibroblast growth factor receptor
D) Thyroid receptor
E) Epidermal growth factor receptor

Question 10

Which of the following is an extracellular messenger involved in signal transduction?

A) Cyclic GMP
B) Ca2+
C) Epinephrine
D) Rhodopsin
E) Diacylglycerol

Question 11

Name the amino acid residue that is used to complex zinc ions in the zinc finger motif of steroid receptors.

Question 12

Receptor tyrosine kinases are membrane-spanning proteins with an intrinsic tyrosine kinase domain on the extracellular side of the membrane.

Question 13

The drug tamoxifen can be used as an anti-cancer drug in some breast tumors as it binds to the ________ but does not activate estrogen-responsive genes.

Question 14

Which of the following compounds can act as second messengers in signal transduction pathways?

A) Cyclic AMP
B) Phospholipase C
C) Adenylate cyclase
D) Phosphotidylinositol 4,5-bisphosphate
E) Both A and D