Multiple choice

When the nucleus of a red blood cell present in a frog, which does not replicates DNA, is transplanted into an enucleated frog egg, the egg goes through several cell divisions. Which of the following is the best interpretation for this phenomenon?

  1. Isolated red blood cell nuclei synthesises DNA.

  2. Nucleus plays no role in cell division.

  3. Enucleated frog egg can divide.

  4. Cytoplasm controls nuclear DNA replication.

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When a differentiated nucleus (from red blood cell that doesn't normally replicate DNA) is transplanted into an enucleated egg, the egg's cytoplasm reprograms the nucleus. The cytoplasm contains factors that can reactivate dormant genes and initiate DNA replication and cell division, demonstrating that cytoplasmic factors control nuclear activity.