Wednesday, November 27, 2013

Human chromosomes

Chromosome: Discrete unit of genome carrying many genes. Each chromosome consists of very long molecule of duplex DNA and approximately equal mass of proteins.
Each species have their unique number of chromosomes. All Human cells contain 23 pairs of chromosome, which is a total of 46 chromosomes in each cell. Human body cells have two of each type of chromosome, which means that their chromosome number is diploid (2n). 22 of the pairs are called autosomes and are numbered from largest to smallest. The autosomes are not involved in determining sex. The two members of each pair have the same length and shape, and they hold information about the same traits, Except for a pairing of sex chromosomes (XY) in males,
The 23rd pair are the sex chromosomes:
  •  XX in females
  •  XY in males