# DBT JRF 2022 — Question 67

Exam: DBT JRF 2022 · Section: B · Topic: Physiology › Chemical Synapses & Neurotransmission · Difficulty: Medium

## Question

Which one of the following is NOT applicable for a chemical synapse?

## Options

- **A.** Usually synaptic cleft is approx. 20 - 40 nm.
- **B.** May release excitatory or inhibitory neurotransmitter.
- **C.** Cannot modulate signal intensity.
- **D.** There is a delay of signal propagation.

## Answer

Option C

## Explanation

Chemical synapses and signal modulation: Chemical synapses CAN modulate signal intensity through multiple mechanisms: • Amount of neurotransmitter released (vesicle fusion frequency, quantal content) • Number of postsynaptic receptors (receptor upregulation/downregulation) • Receptor sensitivity (phosphorylation state, desensitisation) • Temporal summation (multiple signals within a short period) • Spatial summation (signals from multiple synapses) • Neuromodulators (dopamine, serotonin) can modulate the efficacy of synaptic transmission The INCORRECT statement would be: 'Chemical synapses cannot modulate signal intensity' — this is FALSE. Chemical synapses are actually superior to electrical synapses in their ability to modulate, amplify, or dampen signals. Answer: The statement 'chemical synapses cannot modulate signal intensity' is INCORRECT.

Source: https://mypyqbuddy.com/questions/which-one-of-the-following-is-not-applicable-6a104cd5920734408bc0c752