This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses on “Gated Ion Channels”.
1. Which of the following statements is true about transmembrane electrical potential?
a) The chemical gradient drives Cl– and K+ inwards
b) The electrical gradient drives Na+ and Ca+2 inwards
c) The chemical gradient drives Na+ and Ca+2 inwards and K+ outward
d) The chemical gradient drives Cl– and K+ outwards
Explanation: The chemical gradient drives Na+ and Ca+2 inwards and K+ outward, electrical gradient drives Cl–.
2. Nicotinic acetylcholine receptor is an example of
a) Ligated gated receptor channel
b) Serpentine receptors
c) Adhesion receptors
d) Receptor enzymes
Explanation: Nicotinic acetylcholine receptor is an example of ligated gated receptor channel.
3. Which of the following are intracellular second messengers?
Explanation: Inositol triphosphate together with diacylgycerol is a secondary messenger used in signal transduction and lipid signaling in cells.
4. The receptor channels for which of the following are gated by extracellular ligands?
Explanation: The receptor channels for glycine are gated by extracellular ligands.
5. Which of the following statements is false about a ligand-gated ion channel receptor?
a) They are present in the cell membrane
b) They consist of five glycoproteins
c) Differences in membrane potential affect whether the channel receptors are open or close
d) Neurotransmitters can act as the chemical messengers for these channels
Explanation: Ligands affect whether the channel receptors are open or close in a ligand-gated ion channel whereas voltage gated ion channels are controlled by the differences in membrane potential affect.
6. Voltage regulation means
a) Na+/K+ pumps controls potential
b) Unless the voltage is regular gates will not respond
c) Oscilloscope only can control potential
d) With changes in the membrane potential voltage gated ion channels open and close
Explanation: With changes in the membrane potential voltage gated ion channels open and close, this is regulation of voltage.
7. Depolarization and repolarization changes that occur during the action potential are produced by
a) Negative feedback loops
b) Carrier mediated transport
c) Simple diffusion of ions down their concentration gradient
d) Active transport pumps along the neuron membrane
Explanation: Na+ channels open at the beginning of action potential and moves into the axon causing depolarization, when K+ channels open repolarization takes place and moves out of the axon.
8. Diffusion of K+ out of the cell makes the inside of it less positive, or more negative and acts to restore the original resting membrane potential. This process is called
Explanation: Diffusion of K+ out of the cell makes the inside of it less positive, or more negative and acts to restore the original resting membrane potential. This process is called repolarization.
9. Which of the following statements about action potential is false?
a) Na+/K+ pumps are directly involved in creating the action potential
b) Na+ and K+ concentrations are not significantly changed during an action potential
c) This includes both positive and negative feedback loops
d) Only a relatively small number of Na+ and K+ actually diffuse across the membrane
Explanation: The concentration of K+ is higher inside and concentration of Na+ is more outside.
10. Which out of the following is not a neurotransmitter?
b) Cyclic AMP
d) Acetyl choline
Explanation: Cyclic AMP is a secondary messenger molecule controlled by hormones and neurotransmitters.
Sanfoundry Global Education & Learning Series – Biochemistry.
To practice all areas of Biochemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.