AP Biology Chapter 11 Quiz

Question 1

Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because

Answer 1

they amplify the original signal manyfold.

Question 2

Binding of a signal molecule to which type of receptor leads directly to a change in the distribution of anions and/or cations on opposite sides of the membrane?

Answer 2

ligand-gated ion channel

Question 3

The activation of receptor tyrosine kinases is always characterized by

Answer 3

dimerization and phosphorylation.

Question 4

Which of the following provides the best evidence that cell-signaling pathways evolved early in the history of life?

Answer 4

Signal transduction molecules found in distantly related organisms are similar.

Question 5

Which observation suggested to Sutherland the involvement of a second messenger in epinephrine’s effect on liver cells?

Answer 5

Glycogen breakdown was observed only when epinephrine was administered to intact cells.

Question 6

Protein phosphorylation is commonly involved with all of the following except

Answer 6

activation of G-protein-linked receptors.

Question 7

Amplification of a chemical signal occurs when

Answer 7

a receptor in the plasma membrane activates several G-protein molecules while a signal molecule is bound to it.

Question 8

Lipid-soluble signal molecules, such as testosterone, cross the membranes of all cells but affect only target cells because

Answer 8

intracellular receptors are present only in target cells.

Question 9

Signal transduction pathways benefit cells for all of the following reasons except

Answer 9

they help cells use up phosphate generated by ATP breakdown.

Question 10

Consider this pathway: epinephrine > G-protein-linked receptor > G protein > adenylyl cyclase > cAMP. Identify the second messenger.

Answer 10

cAMP