How many chromosomes are present in the human body?

a. 23 nos.

b. 23 pairs

c. 46 pairs

d. 44 pairs

The human body contains a total of 46 chromosomes, which are organized into 23 pairs. So, the correct answer to your question is b. 23 pairs. Let’s break this down further to understand why this is the case.

Understanding Chromosomes

Chromosomes are structures within our cells that carry genetic information. They are made up of DNA and proteins, and they play a crucial role in heredity, development, and functioning of living organisms. In humans, chromosomes come in pairs, with one chromosome of each pair inherited from each parent.

Chromosome Count in Humans

Humans typically have 46 chromosomes, which are arranged in 23 pairs. Each pair consists of one chromosome from the mother and one from the father. This means that:

• There are 22 pairs of autosomes, which are the non-sex chromosomes.
• There is 1 pair of sex chromosomes, which determine an individual's sex. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

Why 23 Pairs?

The reason for having pairs is rooted in sexual reproduction. When a sperm and an egg unite during fertilization, they each contribute half of the genetic material, resulting in a complete set of chromosomes. This pairing is essential for genetic diversity and proper development.

Chromosomal Abnormalities

Sometimes, individuals may have an abnormal number of chromosomes due to errors in cell division. For example, Down syndrome is caused by an extra copy of chromosome 21, leading to a total of 47 chromosomes instead of the usual 46. Such conditions highlight the importance of having the correct number of chromosomes for normal development and health.

Summary

To sum it up, humans have 46 chromosomes organized into 23 pairs. This structure is fundamental to our genetic makeup and plays a vital role in inheritance and biological functions. Understanding this concept is crucial for studying genetics, biology, and medicine.