In a typical eukaryotic cell, where does translation of mRNA into protein primarily occur?

• A. In the nucleus on chromatin
• B. In the Golgi apparatus where mRNA is decoded into polypeptides
• C. Inside lysosomes where proteins are assembled
• D. On ribosomes in the cytosol, including ribosomes bound to the rough endoplasmic reticulum

Answer: (D)

Verified step by step guidance

1. Understand the process of translation, which is the synthesis of proteins from messenger RNA (mRNA). This process involves decoding the mRNA sequence to build a polypeptide chain.
2. Recall that translation occurs in the cytoplasm of eukaryotic cells, specifically on ribosomes. Ribosomes can be free-floating in the cytosol or attached to the rough endoplasmic reticulum (RER).
3. Recognize that the nucleus is the site of transcription (DNA to mRNA), not translation, so translation does not occur on chromatin inside the nucleus.
4. Note that the Golgi apparatus is involved in modifying, sorting, and packaging proteins after they are made, but it does not perform translation.
5. Understand that lysosomes are involved in degradation and recycling of cellular components, not in protein synthesis or assembly.