Question

The given diagram shows a stage during mitotic division in an animal cell:

1. Identify the stage. Give a reason to support your answer.
2. Draw a neat labeled diagram of the cell as it would appear in the next stage. Name the stage.
3. In what two ways is cytokinesis in an animal cell different from the cytokinesis in a plant cell?
4. Name the type of cell division that occurs during-

1. Growth of a shoot.
2. Formation of pollen grains.

Answer 1

1. Identification of the stage:

1. Mitotic division refers to the nuclear division in which the parent cell divides and produces two identical daughter cells.
2. In the given diagram, the chromosomes are aligned at the equatorial plate through spindle fibers to both poles.
3. The centrioles are present at the opposite poles and mitotic spindles are formed.
4. Thus the given diagram represents the metaphase stage of mitotic division.

2. Stage after the stage shown in (1)

1. The next stage that follows metaphase is known as anaphase.
2. In this stage, each chromosome aligned at the equatorial plate splits and the two daughter chromatids, now denoted as daughter chromosomes of the daughter nuclei, begin to migrate towards the two opposite poles.
3. The diagram for anaphase is given in the image below.

3. Cytokinesis:

1. Plant cell cytokinesis occurs in centrifugal order.
2. Animal cell cytokinesis occurs in centripetal order.

Difference between cytokinesis in plant and animal cells:

Cytokinesis in plant cell cytokinesis	Cytokinesis in animal cells
The cytoplasm divide by forming a cell plate in the middle of the cell.	The cytoplasm divide by forming a cleavage furrow on both sides of the cell.
In this process, the cell plate moves from the center to outward.	In this process, the cleavage furrow moves from outward to the center.
The cell centre wall does not constrict.	Cell wall constricts.

4. Type of cell division seen in different stages of plant growth

1. Cell division during growth of a shoot: During the growth of a shoot, mitotic cell division occurs.
2. Cell division during the formation of pollen grains: Pollen grains formation occurs in the anther sac by meiotic cell division.