Which of the following types of RNA molecule can be described as soluble, relatively small and having a folded compact shape

Options

A. rRNA
B. tRNA
C. mRNA
D. Nucleolar RNA

Answer

To solve the question regarding which type of RNA molecule can be described as soluble, relatively small, and having a folded compact shape, we can follow these steps:

### Step 1: Identify the Types of RNA
The main types of RNA in cells are:
- Ribosomal RNA (rRNA)
- Transfer RNA (tRNA)
- Messenger RNA (mRNA)

### Step 2: Analyze Each Type of RNA
1. **Ribosomal RNA (rRNA)**:
- It is a major component of ribosomes.
- Constitutes about 70-80% of total RNA content.
- Generally larger and not described as "small" or "compact" in shape.

2. **Transfer RNA (tRNA)**:
- Functions as an adapter molecule in protein synthesis.
- Constitutes about 5-10% of total RNA content.
- It is relatively small and has a folded, compact structure, which allows it to carry amino acids to the ribosome during translation.

3. **Messenger RNA (mRNA)**:
- It is a linear molecule that carries genetic information from DNA to the ribosome.
- It is typically the longest of the RNA types and not described as "small" or "compact".

### Step 3: Conclusion
Based on the analysis, the RNA type that is soluble, relatively small, and has a folded compact shape is **tRNA**.

### Final Answer
The correct answer is **tRNA (option 2)**.

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