Question 1

Which of the following best describes the role of transmitter-gated ion channels at a chemical synapse?

Accepted Answer

They convert chemical signals into electrical signals in the postsynaptic cell.

Question 2

Which ion influx is primarily responsible for depolarizing the postsynaptic membrane at an excitatory synapse?

Accepted Answer

Na$$^+$$

Question 3

What is the effect of inhibitory neurotransmitters such as GABA on the postsynaptic membrane?

Accepted Answer

They open Cl$$^-$$ channels, hyperpolarizing the membrane.

Question 4

Which of the following drugs acts by making the postsynaptic cell more sensitive to GABA?

Accepted Answer

Barbiturates

Question 5

At the neuromuscular junction, which receptor is responsible for initiating muscle contraction?

Accepted Answer

Acetylcholine-gated cation channel

Question 6

Which of the following best explains why the influx of Cl$$^- at an $$inhibitory synapse suppresses the production of an action potential?

Accepted Answer

Cl$$^-$$ influx hyperpolarizes the membrane, making it harder to reach threshold.

Question 7

Which of the following is a correct sequence of events at a chemical synapse?

Accepted Answer

Action potential arrives at presynaptic terminal → Neurotransmitter released → Neurotransmitter binds to postsynaptic receptor

Question 8

Which of the following neurotransmitters is classified as excitatory and acts through Na$$^+$$ and Ca$$^{2+}$$ channels?

Accepted Answer

Glutamate

Question 9

A patient is given a drug that blocks the reuptake of serotonin. What is the likely effect on synaptic transmission?

Accepted Answer

Increased serotonin in the synaptic cleft, enhancing excitatory signaling.

Question 10

Which of the following best describes the difference between excitatory and inhibitory synapses?

Accepted Answer

Excitatory synapses open Na$$^+ or Ca$^{2+}$$ channels, while inhibitory synapses open Cl$$^-$$ channels.

Question 11

Which of the following is a direct result of acetylcholine binding to its receptor at the neuromuscular junction?

Accepted Answer

Opening of ligand-gated cation channels in the muscle cell membrane

Question 12

Which of the following statements about the structure of a neuromuscular junction is correct?

Accepted Answer

The presynaptic terminal contains synaptic vesicles filled with acetylcholine.

Question 13

Which of the following best explains why transmitter-gated ion channels are major targets for psychoactive drugs?

Accepted Answer

They directly control the flow of ions that alter neuronal excitability.

Question 14

A mutation causes the postsynaptic cell to lack functional Cl$$^-$$ channels. What is the most likely effect on synaptic transmission?

Accepted Answer

Inhibitory neurotransmitters will fail to suppress action potentials.

Question 15

Which of the following is a multi-step process that occurs during muscle contraction at the neuromuscular junction?

Accepted Answer

Acetylcholine binds to its receptor, opening Na$$^+$$ channels, leading to depolarization and subsequent Ca$$^{2+}$$ release from the sarcoplasmic reticulum.

15:Membrane Transport and Energy Conversion in Cell Biology

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