1. What is receptor desensitization?
A.
A decrease in cellular response after prolonged exposure to a signal
B.
An increase in hormone production by a gland
C.
The formation of a new cell membrane
D.
The permanent destruction of all receptors
Correct Answer:
A decrease in cellular response after prolonged exposure to a signal
Explanation:
Receptor desensitization occurs when a cell responds less strongly to continuous or repeated stimulation by a hormone or other signal.
2. Which situation most commonly causes receptor desensitization?
A.
Brief exposure to a very low signal concentration
B.
Continuous exposure to a high signal concentration
C.
Complete absence of a signal
D.
Formation of additional target cells
Correct Answer:
Continuous exposure to a high signal concentration
Explanation:
Continuous exposure to a high concentration of a signaling molecule can make receptors less responsive, producing desensitization.
3. What is the main effect of receptor desensitization on a target cell?
A.
The cell becomes less responsive to the same signal
B.
The cell always divides more rapidly
C.
The cell produces a different hormone immediately
D.
The cell loses all of its DNA
Correct Answer:
The cell becomes less responsive to the same signal
Explanation:
Desensitization reduces the response of a target cell even when the signaling molecule is still present.
4. Which change can contribute to receptor desensitization?
A.
Modification of the receptor so it signals less effectively
B.
Increase in the size of the nucleus only
C.
Complete removal of all hormones from the blood
D.
Production of extra chromosomes
Correct Answer:
Modification of the receptor so it signals less effectively
Explanation:
A receptor may be chemically modified, such as by phosphorylation, causing it to transmit a weaker signal.
5. Receptor desensitization helps a cell to:
A.
Prevent excessive responses to a continuing signal
B.
Respond more strongly to every signal
C.
Stop using its cell membrane
D.
Create a new endocrine gland
Correct Answer:
Prevent excessive responses to a continuing signal
Explanation:
Desensitization protects cells from overstimulation by reducing their response to persistent signals.
6. What may happen to receptors during desensitization?
A.
They may be removed from the cell surface
B.
They may become chromosomes
C.
They may change into hormones
D.
They may produce oxygen directly
Correct Answer:
They may be removed from the cell surface
Explanation:
Cells can internalize or reduce the number of receptors on their surface, making them less sensitive to the signaling molecule.
7. If a cell is desensitized to a hormone, which observation is most likely?
A.
The same hormone concentration produces a smaller response
B.
The hormone always produces a larger response
C.
The cell becomes unable to contain cytoplasm
D.
The hormone changes into a receptor
Correct Answer:
The same hormone concentration produces a smaller response
Explanation:
A defining feature of receptor desensitization is a reduced cellular response to the same amount of hormone.
8. Which process can restore sensitivity after receptor desensitization?
A.
Removal of the signal followed by receptor recovery
B.
Permanent increase in signal concentration
C.
Continuous stimulation without interruption
D.
Destruction of the target cell's membrane
Correct Answer:
Removal of the signal followed by receptor recovery
Explanation:
When the stimulus is removed, receptors may return to an active state or be replaced, allowing the cell to regain sensitivity.
9. How does receptor desensitization differ from increased receptor sensitivity?
A.
Desensitization decreases the response to a signal
B.
Desensitization increases the response to a signal
C.
Desensitization produces more signaling molecules outside the cell
D.
Desensitization changes a receptor into a ribosome
Correct Answer:
Desensitization decreases the response to a signal
Explanation:
Receptor desensitization means that receptor signaling becomes weaker, whereas increased sensitivity would produce a stronger response.
10. Why is receptor desensitization important in hormone action?
A.
It helps maintain balanced cellular responses to hormones
B.
It ensures that every hormone signal remains permanently active
C.
It prevents hormones from being made in all organisms
D.
It changes all target cells into nerve cells
Correct Answer:
It helps maintain balanced cellular responses to hormones
Explanation:
By reducing responses to persistent hormone stimulation, receptor desensitization helps prevent excessive or unbalanced cellular activity.
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