Concise Selina Solutions for Class 10 Biology Chapter 2 Structure of Chromosomes, Cell Cycle and Cell Division


A chromosome is an organized structure of DNA and protein found in cells. During animal cell division, the centrosome divides, and the centrioles replicate (make new copies). In contrast, each chromosome in its condensed form consists of two chromatids joined at some point along the length. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure. Chromosomes are not visible in the cell's nucleus - not even under a microscope - when the cell is not dividing. DNA and histone proteins are packaged into structures called chromosomes.

Cell division:

It is a process by which one single cell gives rise to two or more cells.

Cell Cycle:

The cell cycle, or cell-division cycle, is the series of events that take place in a cell that causes it to divide into two daughter cells. During interphase, the cell grows, accumulating nutrients needed for mitosis, and replicates its DNA and some of its organelles. The cell cycle is the replication and reproduction of cells, whether in eukaryotes or prokaryotes. It is important to organisms in different ways, but overall it allows them to survive. Plants require the cell cycle to grow and provide a life for every other organism on earth.