Question 1

The junction between two neurons across which an impulse passes is the:

Accepted Answer

Synapse. A synapse is the junction between the axon terminal of one neuron and the dendrite of the next.

Question 2

At a chemical synapse, the impulse is transmitted by molecules called:

Accepted Answer

Neurotransmitters. Neurotransmitters (e.g. acetylcholine) diffuse across the synaptic cleft to relay the impulse.

Question 3

The arrival of an impulse at the axon terminal causes the entry of ______, triggering neurotransmitter release:

Accepted Answer

Ca²⁺ ions. Ca²⁺ influx at the terminal makes synaptic vesicles fuse and release neurotransmitter into the cleft.

Question 4

At an electrical synapse, impulse transmission is ______ than at a chemical synapse:

Accepted Answer

Faster (almost instant, via direct current flow). Electrical synapses allow direct, very fast current flow between cells; chemical synapses are slower (with a synaptic delay).

Question 5

Neurotransmitters are released from the pre-synaptic terminal by:

Accepted Answer

Exocytosis of synaptic vesicles into the synaptic cleft. Synaptic vesicles fuse with the pre-synaptic membrane and release neurotransmitter by exocytosis.

Question 6

The key difference between chemical and electrical synapses is that chemical synapses:

Accepted Answer

Use neurotransmitters and have a synaptic delay; electrical use direct ion flow with no delay. Chemical synapses transmit via neurotransmitters (with a brief delay); electrical synapses conduct current directly and rapidly.

Synapse & Transmission — NEET Biology MCQs with Solutions

Questions with solutions