Mitosis in Onion Tip cells and Meiosis in Locust Testis Squash Cells

Authors Avatar by zeynep_merve10hotmailcouk (student)

Mitosis in Onion Root Tip Cells

The chromosomes in onion root tip cells go through interphase where they replicate and form 92 haploid chromosomes from 46 haploid chromosomes, this happens specifically in S phase. However the chromosomes are loose, not completely tightly coiled; therefore, they are named ‘chromatin’ and they haven’t yet formed diploid structures. At this phase the nuclear membrane still exists.

Prophase is when the 92 haploid chromosomes condense and take the shape of fat fingers, forming 46 diploid chromosomes. Each diploid structure consists of two identical sister chromatids. The centriole splits into two daughter centrioles and moves to the opposite poles of the cell in order to conduct the separation of the centromere, which is the area that binds the sister chromatids.

Metaphase is when all 46 diploid chromosomes align in the equator of the cell by the manoeuvring of spindle fibres (products of centrioles). The spindle fibres hold on to the centromere of the chromosome to accomplish the task of aligning them.

In Anaphase the centromeres separate and the spindle fibres shorten in order to pull the sister chromatids to the opposite poles of the cell. Now, there are 46 haploid chromosomes on each pole of the cell. The chromosomes are still in the shape of fat fingers.

Join now!

During Telophase, the spindle fibres break down and disappear, allowing the nuclear membrane to re-appear around the two sets of 46 haploid chromosomes on opposite poles of the cell. The nucleolus also reforms. The chromosomes become uncoiled (spaghetti-like).

The process of cytokinesis occurs as the cell is compressed from the middle and divided into two; two identical daughter cells that each contain 46 haploid chromosomes form. These daughter cells also contain the same genetic material as the original parent cell. Once this process is over, the organelles begin to reform as well.

Meiosis in Locust Testis Squash Cells

The ...

This is a preview of the whole essay