Question

How is the process of mitosis different between eukaryotic phytoplankton (e.g., diatoms and dinoflagellates) and most other eukaryotes?

a. he nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates.
b. Diatoms and dinoflagellates undergo the same cell nuclear division as other eukaryotes.
c. Diatoms and dinoflagellates do not undergo mitosis, while other eukaryotes undergo a similar mitotic process.
d. Diatoms and dinoflagellates undergo mitosis with a different cell nucleus structure compared to most other eukaryotes.

Answer 1

Eukaryotic phytoplankton such as diatoms and dinoflagellates undergo a type of mitosis called closed mitosis, where the nuclear envelope remains intact and the spindle apparatus operates from outside the nucleus, unlike in most other eukaryotes.

Step-by-step explanation:

The process of mitosis is different between eukaryotic phytoplankton, such as diatoms and dinoflagellates, and most other eukaryotes in the way that the nuclear envelope behaves during cell division. In most eukaryotes, the nuclear envelope breaks down during the early stages of mitosis, allowing the chromosomes to separate freely within the cell. However, in diatoms and dinoflagellates, mitosis is closed, meaning that the nuclear envelope does not disintegrate. Instead, the spindle apparatus forms outside the intact nuclear envelope and separates the chromosomes. Dinoflagellates possess a unique type of nucleus called a dinokaryon. In the dinokaryon, chromosomes remain highly condensed throughout the cell cycle and lack typical histones, which is a significant deviation from most eukaryotic cells.