Which statement about visualizing nucleoli is true?

Which statement about visualizing nucleoli is true?

• A. Nucleoli are larger in actively producing cells.
• B. Nucleoli have identical morphology in all cell types.
• C. Nucleoli persist unchanged throughout mitosis.
• D. Nucleoli are located in the cytoplasm.

Answer: (A)

Visualizing nucleoli hinges on their role in ribosome production. When a cell is actively making ribosomes, rRNA transcription in the nucleolus is high and many ribosomal components accumulate there, causing the nucleolus to enlarge and become more conspicuous under light microscopy. In cells with lower ribosome production, the nucleolus is smaller or less prominent. Nucleoli reside within the nucleus, not in the cytoplasm, and they disassemble during mitosis and reassemble afterward, so they don’t persist unchanged through cell division. Variation in nucleolar size and appearance among different cell types also reflects differing levels of ribosome biogenesis. Therefore, the statement that nucleoli are larger in actively producing cells is the true one.

Visualizing nucleoli hinges on their role in ribosome production. When a cell is actively making ribosomes, rRNA transcription in the nucleolus is high and many ribosomal components accumulate there, causing the nucleolus to enlarge and become more conspicuous under light microscopy. In cells with lower ribosome production, the nucleolus is smaller or less prominent. Nucleoli reside within the nucleus, not in the cytoplasm, and they disassemble during mitosis and reassemble afterward, so they don’t persist unchanged through cell division. Variation in nucleolar size and appearance among different cell types also reflects differing levels of ribosome biogenesis. Therefore, the statement that nucleoli are larger in actively producing cells is the true one.