An electrical synapse differs from a chemical synapse in that the electrical synapse :

Options

A. has more varied signals crossing the synapse
B. has wider clefts between the presynaptic and postsynaptic membranes
C. is found only in vertebrates
D. is much faster, having essentially instantaneous transmission

Explanation

### Step-by-Step Solution:

1. **Understanding Synapses**:
- Synapses are connections between neurons that allow them to communicate. There are two main types: electrical synapses and chemical synapses.

2. **Nature of Signals**:
- **Electrical Synapse**: This type of synapse transmits signals through direct electrical connections between neurons. The transmission occurs via gap junctions, allowing ions to flow directly from one neuron to another.
- **Chemical Synapse**: In contrast, chemical synapses transmit signals using neurotransmitters. When an electrical impulse reaches the end of a neuron, it triggers the release of these chemicals into the synaptic cleft, where they bind to receptors on the next neuron.

3. **Speed of Transmission**:
- Electrical synapses allow for much faster transmission of signals compared to chemical synapses. This is because electrical signals can travel almost instantaneously through gap junctions, while chemical synapses require the release and diffusion of neurotransmitters, which takes more time.

4. **Comparison of Properties**:
- Electrical synapses have a narrower synaptic cleft compared to chemical synapses, which have a wider cleft due to the presence of the synaptic gap filled with neurotransmitters.
- Electrical synapses are found in both vertebrates and invertebrates, while chemical synapses are more common in vertebrates.

5. **Conclusion**:
- The key difference highlighted in the question is that electrical synapses are much faster and provide essentially instantaneous transmission of signals compared to chemical synapses.

### Final Answer:
An electrical synapse differs from a chemical synapse in that the electrical synapse is much faster, having essentially instantaneous transmission.

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