Ribosome

Options

A. Consists of one large and two small subunits
B. Contains identical components in prokaryote and eukaryote
C. is the only site of RNA replication
D. has two or three major sites to which tRNA can be bound.

Answer

### Step-by-Step Solution:

1. **Understanding Ribosome Structure**:
- Ribosomes are cellular structures responsible for protein synthesis. They are composed of two subunits: a large subunit and a small subunit. In eukaryotes, these are referred to as 80S ribosomes, while in prokaryotes, they are known as 70S ribosomes.

2. **Identifying Components**:
- The ribosome consists of ribosomal RNA (rRNA) and proteins. The large subunit typically contains more rRNA and proteins than the small subunit. This structural difference is crucial for their function in translation.

3. **Binding Sites**:
- Ribosomes have multiple binding sites for RNA. Specifically, there are four binding sites: one for messenger RNA (mRNA) and three for transfer RNA (tRNA). These sites are essential for the ribosome to read the mRNA sequence and assemble the corresponding amino acids into a polypeptide chain.

4. **Function of Ribosomes**:
- Ribosomes are not the site of RNA replication; instead, they are the sites where protein synthesis occurs. The process involves decoding the mRNA and using tRNA to bring the appropriate amino acids to form proteins.

5. **Conclusion**:
- Based on the information, the correct statement regarding ribosomes is that they have two or three major sites to which tRNA can bind. The other options provided in the question are inaccurate.

### Final Answer:
- The correct option is that ribosomes have two or three major sites to which tRNA can be bound.

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