Chapter 29, Problem 32A

Summary Introduction

To sketch: the four phases of mitosis in a cell with two chromosomes.

Introduction:

Mitosis is a type of cell division in which one cell divides to form two new cells. The new cells formed are known as daughter cells and cell from which they are formed are known as mother cells. In mitosis division daughter cell formed are genetically identical to mother cell. Mitosis have four phases, they are prophase, metaphase, anaphase and telophase.

Explanation of Solution

Four phase of mitosis-:

Prophase − prophase is first and longest phase of mitosis. In prophase chromatin condenses into chromosomes, nuclear envelope breaks down. Centrioles near nucleus start to separate and moves to the opposite poles of the cells. As centrioles move towards poles, spindle starts forming.

Metaphase − In metaphase spindle fibers attach to the centromere of each pair of sister chromatids and each chromosome is lined up on the equator or centre of the cell.

Anaphase − In anaphase centromeres divides and sister chromatids starts to separate. Sister chromatids are separated by shortening of spindle fibres. Each sister chromatids moves in an opposite direction to the opposite poles.

Telophase − In telophase chromosome reaches the opposite pole and starts decondensing. Spindles start to disappear and two nuclei form in a cell.

Conclusion