Chapter 9.2, Problem 1NV

Summary Introduction

To determine:

Definition of the terms prophase, sister chromatid, centromere, spindle apparatus, metaphase, anaphase, and telophase.

Introduction : 

A cell is the basic unit of life and a series of events that take place in a living cell during its life is known as the cell cycle. In the last M stage or the mitotic phase of the cell cycle, a cell is divided into two. The mitosis itself is divided into four sub-stages, these are prophase, metaphase, anaphase, and telophase.

Explanation of Solution

Prophase: The first phase of the mitotic division is prophase. In the cells, the genetic material is present in an uncoiled manner. So, for the cell division to occur, the DNA (deoxyribonucleic acid) needs to be condensed to form a chromosome. In a eukaryotic cell, the prophase starts with the condensation of the DNA to form chromosomes and the nuclear membrane disappears.

Sister chromatid: It is identical copies of chromatids, replication of a chromosome. These sister chromatids are joined together at a common centromere.

Centromere: It is the center of the chromosome at which spindle fibers attach to the sister chromatids.

Spindle apparatus: It is a protein structure, which divides the chromosome of the parent cells equally into two parts, which form the chromosome of the daughter cells.

Metaphase: The next phase to prophase is metaphase. At this stage, the condensed chromosomes lie at the equator of the cells.

Anaphase: At this stage, the pull of spindle fibers causes the separation of sister chromatids of chromosomes and leads to the movement of the chromatids to opposite poles. At the end of the anaphase, the movement of chromatids to the opposite pole is completed.

Telophase: It is the last phase of the cell division, in which the chromosomes decondense at the opposite ends and the nuclear envelope of the future daughter cells are formed.