1. Where are membrane-bound receptors located?
A.
Inside the cell nucleus
B.
On the plasma membrane
C.
In the mitochondria
D.
Inside the ribosome
Correct Answer:
On the plasma membrane
Explanation:
Membrane-bound receptors are proteins embedded in or attached to the plasma membrane of a cell.
2. What usually binds to a membrane-bound receptor to begin cell signaling?
A.
An extracellular signaling molecule
B.
A ribosomal RNA molecule
C.
A DNA nucleotide
D.
A mitochondrial enzyme
Correct Answer:
An extracellular signaling molecule
Explanation:
A signaling molecule outside the cell binds to the receptor on the plasma membrane and initiates a cellular response.
3. Which type of signaling molecule commonly uses membrane-bound receptors because it cannot easily cross the plasma membrane?
A.
A hydrophilic hormone
B.
A small lipid-soluble hormone
C.
Oxygen
D.
A fatty acid stored in a membrane
Correct Answer:
A hydrophilic hormone
Explanation:
Hydrophilic hormones cannot readily pass through the lipid bilayer, so they bind to receptors on the cell membrane.
4. What is the main function of a membrane-bound receptor?
A.
To detect an external signal and start a cellular response
B.
To produce oxygen for the cell
C.
To copy DNA directly
D.
To digest cellular waste
Correct Answer:
To detect an external signal and start a cellular response
Explanation:
Membrane-bound receptors recognize external signaling molecules and transmit their information into the cell.
5. Which receptor is associated with a G protein on the inner side of the plasma membrane?
A.
G-protein-coupled receptor
B.
Nuclear receptor
C.
Ribosomal receptor
D.
Mitochondrial receptor
Correct Answer:
G-protein-coupled receptor
Explanation:
A G-protein-coupled receptor interacts with a G protein on the cytoplasmic side of the plasma membrane after ligand binding.
6. What happens when a ligand binds to a membrane-bound receptor?
A.
The receptor changes shape and activates signaling
B.
The receptor is converted into DNA
C.
The cell membrane disappears
D.
The ligand becomes a ribosome
Correct Answer:
The receptor changes shape and activates signaling
Explanation:
Ligand binding commonly causes a conformational change in the receptor, allowing it to begin a signaling pathway inside the cell.
7. Which of the following can act as a second messenger in a pathway involving a membrane-bound receptor?
A.
Cyclic AMP
B.
DNA polymerase
C.
Hemoglobin
D.
Cellulose
Correct Answer:
Cyclic AMP
Explanation:
Cyclic AMP is a second messenger produced inside cells after activation of certain membrane-bound receptors.
8. A receptor enzyme that adds phosphate groups to proteins after ligand binding is called a:
A.
Receptor tyrosine kinase
B.
Nuclear receptor
C.
Digestive enzyme
D.
Structural carbohydrate
Correct Answer:
Receptor tyrosine kinase
Explanation:
Receptor tyrosine kinases are membrane-bound receptors that activate signaling by phosphorylating proteins after ligand binding.
9. Why are membrane-bound receptors important for cell communication?
A.
They allow cells to respond to signals outside the cell
B.
They store genetic information
C.
They make all cellular proteins directly
D.
They prevent every substance from entering the cell
Correct Answer:
They allow cells to respond to signals outside the cell
Explanation:
Membrane-bound receptors receive external signals and convert them into intracellular signals that produce a cellular response.
10. Which part of a membrane-bound receptor usually binds the signaling molecule?
A.
The extracellular region
B.
The ribosomal region
C.
The mitochondrial matrix
D.
The nuclear pore
Correct Answer:
The extracellular region
Explanation:
The extracellular part of a membrane-bound receptor recognizes and binds the signaling molecule outside the cell.
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