Concept: This question tests your understanding of the fundamental differences between electrical and chemical synapses, focusing on their structure and the speed of impulse transmission.

Why (A) is incorrect: Impulse transmission across an electrical synapse is significantly faster than across a chemical synapse. This is because electrical synapses involve direct flow of ions through gap junctions, whereas chemical synapses require the release, diffusion, and binding of neurotransmitters, which introduces a synaptic delay.

Why other options are correct:

• (B) In an electrical synapse, the membranes of the presynaptic and postsynaptic neurons are indeed in very close proximity, connected by gap junctions.
• (C) Electrical current (ions) can flow directly from one neuron to another through the gap junctions in an electrical synapse, allowing for rapid and synchronized communication.
• (D) Chemical synapses are characterized by the release of specific chemical messengers called neurotransmitters from the presynaptic neuron into the synaptic cleft, which then bind to receptors on the postsynaptic neuron.

Common Mistake: Students often assume that anything involving chemicals must be slower, but the direct electrical coupling in electrical synapses makes them inherently faster than the multi-step process of chemical synapses.

NEET Tip: Remember that electrical synapses are less common in mammals but are crucial for rapid, synchronized responses, like in cardiac muscle or escape reflexes. Chemical synapses offer more flexibility and modulation.

Correct Answer: (A)