Ch. 11 Quiz

Question 1

What is most likely to happen to an animal’s target cells that lack receptors for local regulators?

Answer 1

They might not be able to multiply in response to growth factors from nearby cells

Question 2

Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding?

a) hormonal signaling
b) autocrine signaling
c) paracrine signaling
d) endocrine signaling
e) synaptic signaling

Answer 2

Paracrine signaling

Question 3

When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway?

Answer 3

signal molecule

Question 4

Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to…

Answer 4

the active site of an allosteric enzyme that binds to a specific substrate

Question 5

Which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP?

a. it would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane
b. it could activate only the epinephrine system
c. it would be able to carry out reception and transduction but would not be able to respond to a signal
d. It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane
e. it would employ a transduction pathway directly from an external messenger

Answer 5

a. It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane

Question 6

One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?

Answer 6

receptor tyrosine kinases

Question 7

Since steroid receptors are located intracellularly, which of the following is true?

Answer 7

The steroid/receptor complex can cross the nuclear membrane

Question 8

Which of the following is the best explanation for the inability of a specific animal cell to reduce the Ca2+ concentration in its cytosol compared with the extracellular fluid?

a) blockage of the synaptic signal
b. loss of transcription factors
c. insufficient ATP levels in the cytoplasm
d. low oxygen concentration around the cell
e. low levels of protein kinase in the cell

Answer 8

c. insufficient ATP levels in the cytoplasm

Question 9

Adenylyl cyclase has the opposite effect of which of the following?

Answer 9

phosphodiesterase

Question 10

What explains the increased concentration of Ca++ in the ER?

Answer 10

Calcium ions are actively imported from the cytoplasm into the ER