Chromosome

Chromosomes are the genetic material present in all cells. They are present in the nucleus of a eukaryotic cell. They are a thread-like structure.

Each chromosome of a eukaryotic cell contains DNA and associated proteins, known as histone proteins. They are responsible for the hereditary traits and passed from parents to offspring from one generation to another. DNA codes for specific proteins and are responsible for variations in a species and among various organisms. Scientists have given this name chromosomes as they are stained using specific dyes, chroma means colour and soma means body.

Properties of Chromosomes

Humans have 23 pairs of chromosomes. This unique structure of the chromosome keeps DNA tightly packed with histone proteins to fit inside the cell and it also helps in giving more stability to it. For instance, the unwound DNA of a single cell will measure 6 feet, with this, one can understand the need for packaging inside the nucleus of each cell.

Cells must continuously repair, grow and regenerate to replace the old cells. Cell division is important for the growth and development of an organism. We can see chromosomes clearly during cell division. Chromosomes ensure that DNA is divided equally between the daughter cells during cell division. Even a small irregularity in the process may lead to various diseases and deformities. Uncontrolled cell division results in tumour cells and causes cancer. Chromosomal aberration like changes in structure or number can cause genetic disorders, e.g. Down’s syndrome, Turner’s syndrome, etc. Defective chromosomes may even lead to a certain type of leukaemia in humans.