What used to be described as Nissl granules in a nerve cell are now identified as

Options

A. ribosomes
B. mitochondria
C. cell metabolites
D. fat granules

Explanation

### Step-by-Step Solution

1. **Understanding Nissl Granules**: Nissl granules are structures found in the cell body of neurons. They were originally identified as a specific type of granule in nerve cells.

2. **Location of Nissl Granules**: These granules are primarily located in the cell body (soma) of the neuron, which contains the nucleus and is responsible for the metabolic activities of the cell.

3. **Function of Nissl Granules**: The main function of Nissl granules is related to protein synthesis. This is crucial for the growth and maintenance of neurons.

4. **Identifying the Components**: Nissl granules are now identified as ribosomes and rough endoplasmic reticulum (ER). Ribosomes are the actual sites of protein synthesis, while the rough ER is involved in the transport of proteins synthesized by ribosomes.

5. **Analyzing the Options**: Given the options in the question, we need to identify which one corresponds to the current understanding of Nissl granules. The options include:
- A) Ribosomes
- B) Mitochondria
- C) Cell metabolites
- D) Fat granules

6. **Selecting the Correct Answer**: Among the options, ribosomes (Option A) are the correct identification of what was previously referred to as Nissl granules. Mitochondria are involved in energy production, cell metabolites are not specific structures, and fat granules are unrelated to protein synthesis.

### Final Answer
Nissl granules in a nerve cell are now identified as **ribosomes**.

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