Hint: A chromosome is a polymer of DNA molecules that forms the genetic material of organisms. Recombination of chromosomes during meiosis and thereafter sexual fertilization forms the diversity in genetics.
There are two types of chromosomes in human beings, they are autosomes and allosomes. Autosomes are the normal chromosomes of the body and allosomes are the sex chromosome. Certain characteristics of the individual are linked to the sex chromosomes and can be passed on to the next generations through the gametes which contain these allosomes. The normal chromosomes or the autosomes contain all the other genetic information based on heredity. The number of chromosomes remains constant in organisms, but the chromosome numbers differ in different species of organisms. Human cells have twenty-three pairs of chromosomes. It consists of twenty-two pairs of autosomes or the normal chromosomes and one pair of sex chromosomes or allosomes. Thus a total of forty-six chromosomes are present in a normal human cell. The sex chromosome type differs in different sexes, and a difference in genetic makeup exists. In females the gametes are made of two X chromosomes, thus the chromosomes in females can be seen as XX. In males the gametes consist of two types of chromosomes, that is one X and one Y chromosome. Thus a male cell consists of XY chromosomes.
Therefore, a human being possesses twenty-two pairs of autosomes and one pair of sex chromosomes.
Note: Any difference in the number of chromosomes in human beings from the twenty-three pairs results in a variety of genetic disorders. These can be caused due to any malfunctions happening during the segregation of the chromosomes or during cell division. The various genetic disorders that can be caused are Down’s syndrome, Turner’s syndrome, and Klinefelter’s Syndrome.