Which of the following correctly matches the structure with its primary function in a eukaryotic cell?

• A. Nuclear envelope – protein synthesis
• B. Ribosome – DNA replication
• C. Nuclear pore – lipid synthesis
• D. Nucleolus – ribosome assembly

Answer: (D)

Verified step by step guidance

1. Understand the question: The problem asks to match cellular structures with their primary functions in a eukaryotic cell. The correct answer provided is 'Nucleolus – ribosome assembly.'
2. Step 1: Recall the function of the nucleolus. The nucleolus is a dense region within the nucleus of eukaryotic cells where ribosomal RNA (rRNA) is synthesized and ribosome subunits are assembled.
3. Step 2: Analyze the incorrect options: The nuclear envelope surrounds the nucleus and regulates the movement of molecules between the nucleus and cytoplasm, but it is not involved in protein synthesis. Ribosomes are responsible for protein synthesis, not DNA replication. Nuclear pores allow the transport of molecules across the nuclear envelope, but they are not involved in lipid synthesis.
4. Step 3: Confirm the correct match: The nucleolus is indeed responsible for ribosome assembly, making 'Nucleolus – ribosome assembly' the correct answer.
5. Step 4: Summarize the reasoning: The nucleolus is the site of ribosome assembly, and the other options incorrectly pair structures with functions that do not align with their roles in the cell.