The step of mitosis in which chromosomes line up along the equatorial plane of the cell is called:
a. Prophase. b. Metaphase. c. Anaphase. d. Telophase.
The correct answer and explanation is:
The correct answer is b. Metaphase.
Explanation:
Mitosis is the process of cell division that results in two genetically identical daughter cells. It consists of several phases: prophase, metaphase, anaphase, and telophase. Each of these stages has a specific role in the division of the cell.
In metaphase, the chromosomes align along the cell’s equatorial plane, also known as the metaphase plate. This is a crucial step in mitosis because it ensures that each daughter cell will receive an identical set of chromosomes. The alignment is achieved through the action of the mitotic spindle, a structure made of microtubules that extends from the centrosomes at opposite ends of the cell. These microtubules attach to the centromeres of the chromosomes, which are the points where the two sister chromatids are connected.
The positioning of the chromosomes in metaphase is critical because it ensures that when the sister chromatids are pulled apart in the next phase, anaphase, they will be evenly distributed between the two daughter cells. If chromosomes do not line up properly, it can lead to errors in the distribution of genetic material, potentially causing mutations or cell death.
Metaphase is preceded by prophase, during which the chromatin condenses into visible chromosomes, and followed by anaphase, where the sister chromatids are separated and moved toward opposite poles of the cell. The final stage, telophase, involves the reformation of the nuclear envelope around the separated chromatids, which then start to de-condense into chromatin. This marks the near end of mitosis and sets the stage for cytokinesis, where the cell’s cytoplasm divides, completing the process of cell division.