Question

You are studying a single-celled eukaryotic organism that has 4 pairs of chromosomes. Please draw how this organism will go through mitosis. In each phase, briefly describe what is happening. Please label the number of chromosomes and chromatids in metaphase and in the resultant daughter cells. (5)

Answer 1

Ans:

Prophase: The individual chromosome is appear as double thread-like structue in this phase. As the phase progress, chromosome become increasingly thicker and shorter. The nucleuolus and nuclear membrane are present at the early stage but at the end of this stage they are disappear.

Metaphase:

1. The nucleolus and nuclear membrane are disappear.

2. In this stage, spindle formation takes place.

3. The chromosomes are shortest and thickest in this stage and more condensed.

4.  The chromosomes are arranged in equitorial plane.

Anaphase:

1. The two sister chromatids of each chromosome separate and migrate to two oppsite poles.

2. IThe movement of of the homologous centromeres to the opposite poles is facilitated by shortening of the firbres thus dragging the chromosome to the opposite poles

Telophase:

1. The nucleolus and nuclear membrane are reappear.

2. The chromosomes become uncoil to thread like structure in this stage.

Cytokinesis:

At the end of this phase the cell plate formation takes place that divide the cells into two daughter cells, each carrying same chromosome number.