Question

Name any two phases of mitosis and describe the cellular activities that occur during that phase.

Answer 1

Mitosis :
Process where a single cell divides into 2 identical daughter cells. Mitosis helps in growth and replacement of worn-out cells

Phases of mitosis are,
* prophase
* metaphase,
* anaphase, and
*telophase.

Prophase :
This stage is again divided into 2
1. Early prophase
2 Late prophase/ Prometaphase

Early prophase :
The chromosomes start to condense.The mitotic spindle begins to form,as the two pairs of centrioles move to opposite poles and microtubules begin to polymerize from the duplicated centrosomes.
The nucleolus disappears. This is a sign that the nucleus is getting ready to break down.

Late prophase :
The chromosomes finish condensing.The nuclear envelope breaks down, releasing the chromosomes.The mitotic spindle grows more, and some of the microtubules start to capture chromosomes.Chromosomes are pulled in opposite directions by microtubules growing out from both poles of the spindle.Kinetochores are formed.They are complex platelike structures that assemble during prometaphase on one face of each sister chromatid at its centromere.At the end of late prophase, the kinetochores on sister chromatids are connected by microtubules to opposite poles of the spindle.

Metaphase:

The centromeres of all the cell's chromosomes line up at the equator of the spindle.At this stage, the cell will check that all the chromosomes are aligned along the metaphase plate, with their kinetochores correctly attached.The two kinetochores of each chromosome should be attached to microtubules from opposite spindle poles.Chromosomes are most easily visualized at this stage.