Which of the following correctly labels the main components of a chemical synapse?

• A. Axon hillock, myelin sheath, dendritic spine
• B. Cell wall, chloroplast, central vacuole
• C. Nucleus, Golgi apparatus, mitochondria
• D. Presynaptic terminal, synaptic cleft, postsynaptic membrane

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the context of the question. A chemical synapse is a specialized junction between two neurons or between a neuron and another cell (e.g., muscle cell) where chemical signals are transmitted.
2. Step 2: Identify the main components of a chemical synapse. These include: (1) the presynaptic terminal, which releases neurotransmitters, (2) the synaptic cleft, which is the small gap between the two cells, and (3) the postsynaptic membrane, which contains receptors to receive the neurotransmitters.
3. Step 3: Analyze the provided options. Eliminate choices that do not relate to the structure of a chemical synapse. For example, 'axon hillock, myelin sheath, dendritic spine' refers to other parts of a neuron, not the synapse. Similarly, 'cell wall, chloroplast, central vacuole' are components of plant cells, and 'nucleus, Golgi apparatus, mitochondria' are general cellular organelles.
4. Step 4: Match the correct components to the chemical synapse. The correct answer is 'Presynaptic terminal, synaptic cleft, postsynaptic membrane,' as these are the structures directly involved in the process of neurotransmission.
5. Step 5: Reinforce the concept by reviewing the function of each component: The presynaptic terminal releases neurotransmitters, the synaptic cleft allows the neurotransmitters to diffuse across, and the postsynaptic membrane contains receptors that bind to the neurotransmitters to propagate the signal.