Question

Which of the following statements are correct for chemical synapse?
(i) Pre and postsynaptic neurons are separated by fluid-filled synaptic cleft.
(ii) Bidirectional conduction of impulses.
(iii) Presence of synaptic vesicles in the axon terminals.
(iv) The membranes of pre-synaptic and post-synaptic neurons are in close proximity.

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (i) and (iii)
• D. (iii) and (iv)

Answer 1

Answer: (C)

Chemical synapses relay information with the help of chemicals. They are slow and steady in nature. A chemical synapse is a gap between two neurons in which the information passes chemically. The chemicals are called as "Neurotransmitter molecules" that are filled in synaptic vesicles present at the axon terminals. The chemicals can increase a signal and can take a long time. In an electrical synapse, the synaptic cleft measures 0.2 nm while in the chemical synapse, it is around 20 nm. This means that the membranes of presynaptic and postsynaptic neurons are not in close proximity. Chemical synapse has unidirectional conduction of impulse. In a chemical synapse, the pre and postsynaptic neurons are separated by a fluid-filled synaptic cleft.