Signal recognition particle or SRP consists of

Options

A. Two scRNA + two proteins
B. 1 sc RNA + 6 proteins
C. 1 sc RNA + 3 proteins
D. 1 sc RNA + 2 proteins.

Answer

To determine what the Signal Recognition Particle (SRP) consists of, we can break down the information as follows:

### Step-by-Step Solution:

1. **Understanding SRP**: The Signal Recognition Particle (SRP) is a ribonucleoprotein complex that plays a crucial role in the targeting of proteins to the endoplasmic reticulum (ER) in eukaryotic cells.

2. **Components of SRP**: The SRP is made up of a specific type of RNA and several proteins. The RNA component is referred to as signal recognition particle RNA (spRNA).

3. **Identifying the RNA**: The spRNA in SRP is also known by various names, including 7SL RNA, 6S RNA, FFF RNA, and 4.5S RNA. This indicates that there is only one RNA molecule present in the SRP.

4. **Counting the Proteins**: In addition to the spRNA, the SRP consists of a total of six proteins that are essential for its function in recognizing the signal peptide of nascent proteins and facilitating their transport to the ribosome.

5. **Final Composition**: Therefore, the complete composition of the Signal Recognition Particle (SRP) is 1 spRNA plus 6 proteins.

6. **Conclusion**: Based on the analysis, the correct answer to the question is that the Signal Recognition Particle (SRP) consists of 1 spRNA plus 6 proteins.

### Final Answer:
The Signal Recognition Particle (SRP) consists of 1 spRNA plus 6 proteins.

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