To initiate translation, the mRNA first binds to

Options

A. the smaller ribosomal sub-unit
B. the larger ribosomal sub-unit
C. the whole ribosome
D. no such specificity exists.

Explanation

To solve the question "To initiate translation, the mRNA first binds to," we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Ribosomes**:
- Ribosomes are the cellular machinery responsible for protein synthesis. They are composed of two subunits: a larger subunit and a smaller subunit.

2. **Identify the Components of Ribosomes**:
- The ribosome consists of ribosomal RNA (rRNA) and proteins. In its inactive form, it exists as two separate subunits.

3. **Recognize the Process of Translation**:
- Translation is the process where the mRNA sequence is decoded to synthesize proteins. This process begins with the binding of mRNA to the ribosome.

4. **Determine Which Subunit Binds First**:
- During the initiation of translation, the smaller ribosomal subunit binds to the mRNA first. This is a crucial step that allows the ribosome to recognize the start codon on the mRNA.

5. **Conclude the Correct Answer**:
- Therefore, the correct answer to the question is that to initiate translation, the mRNA first binds to the **smaller ribosomal subunit**.

### Final Answer:
To initiate translation, the mRNA first binds to the **smaller ribosomal subunit**.

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