Eukaryotic ribosomes are

Options

A. 30S
B. 50S
C. 80S
D. 70S

Answer

### Step-by-Step Solution:

1. **Understanding Ribosomes**: Ribosomes are known as the protein factories of the cell because they are the primary site for protein synthesis. They translate messenger RNA (mRNA) into polypeptide chains, which then fold into functional proteins.

2. **Composition of Ribosomes**: Ribosomes are composed of ribonucleic acids (RNA) and proteins. The RNA component is crucial for the ribosome's function in protein synthesis.

3. **Ribosome Size in Eukaryotes**: In eukaryotic cells, ribosomes are classified based on their sedimentation rates, which are measured in Svedberg units (S).

4. **Subunits of Eukaryotic Ribosomes**: Eukaryotic ribosomes consist of two subunits:
- The larger subunit is 60S.
- The smaller subunit is 40S.

5. **Total Size of Eukaryotic Ribosomes**: When combined, the total size of eukaryotic ribosomes is 80S (60S + 40S).

6. **Conclusion**: Therefore, the correct answer to the question "Eukaryotic ribosomes are" is 80S.

### Final Answer:
Eukaryotic ribosomes are 80S.

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