Biology · Neural Control and Coordination · NEET
| Gap between neurons | Membranes in very close proximity (almost no gap) | Separated by a fluid-filled synaptic cleft |
| How signal passes | Electric current flows directly across | Carried by chemical neurotransmitters |
| Speed | Faster (always faster than chemical) | Slower (has synaptic delay) |
| Neurotransmitter used | No | Yes, released from synaptic vesicles |
| How common in humans | Rare in our system | Common (most human synapses) |
The electrical synapse is faster. NCERT clearly states that impulse transmission across an electrical synapse is always faster than across a chemical synapse. This is because electric current flows directly from one neuron into the next, with no chemical step to slow it down. In a chemical synapse the signal must wait for neurotransmitters to be released, cross the cleft, and bind to receptors, which adds a small delay called synaptic delay.
In an electrical synapse the pre- and post-synaptic membranes lie in very close proximity, so the electric current simply passes straight across, almost like conduction along a single continuous axon. There is no gap to cross and no chemical to make or break. In a chemical synapse there is a fluid-filled synaptic cleft, and the impulse must be converted into a chemical signal (neurotransmitter release) and then back into an electrical signal on the other side. These extra conversion steps take time, so chemical transmission is slower.
No. Neurotransmitters are used only in chemical synapses. In an electrical synapse the current flows directly between the two neurons, so no chemical messenger is needed. This is a very common trap. Only the chemical synapse has vesicles filled with neurotransmitters at the axon terminals that release into the synaptic cleft and bind to receptors on the post-synaptic membrane.
The chemical synapse has a clear fluid-filled synaptic cleft that separates the pre- and post-synaptic membranes. In an electrical synapse the two membranes are in very close proximity, so there is essentially no functional gap for chemicals to cross. NCERT notes the two membranes may or may not be separated by a gap, and it is the chemical synapse where this cleft is important.
No. NCERT states that electrical synapses are rare in our system. Most synapses in the human nervous system are chemical synapses, which use neurotransmitters. So even though electrical synapses are faster, chemical synapses are the usual type you study for NEET, and most exam questions on synaptic transmission describe the chemical synapse.
Select the incorrect statement regarding synapses:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
An electrical synapse passes current directly between neurons that lie very close together, making it fast and needing no chemicals. A chemical synapse has a synaptic cleft and uses neurotransmitters to carry the signal, making it slower.
The chemical synapse is far more common. NCERT states electrical synapses are rare in our system, so most human synapses are chemical and use neurotransmitters.
There is essentially no chemical synaptic delay in electrical synapses because current flows directly. The synaptic delay you learn for NEET belongs to the chemical synapse, caused by neurotransmitter release and binding.
Neurotransmitters bind to their specific receptors present on the post-synaptic membrane. This binding opens ion channels and generates a new potential in the post-synaptic neuron. This point is a repeated NEET favourite (2017, 2026).
