400981 Lecture Notes - Lecture 21: Sister Chromatids, Y Chromosome, Dna Replication

• School: UWS
• Department: University of Western Sydney
• Course: 400981
• Professor: unknown

Document Summary

Meiosis is used by diploid organisms to produce haploid gametes. In a diploid organism such as the human organism, most cells of the body have the diploid amount of dna, 2n. Using this notation for counting chromosomes we say that human somatic cells have 46 chromosomes (2n = 46) while human sperm and eggs have 23 chromosomes (n = 23). Humans have 23 distinct types of chromosomes, the. 22 autosomes and the special category of sex chromosomes. There are two distinct sex chromosomes, the x chromosome and the y chromosome. A diploid human cell has 23 chromosomes from that person"s father and 23 from the mother. That is, your body has two copies of human chromosome number 2, one from each of your parents. Immediately after dna replication a human cell will have 46. In each double chromosome there are two copies of that chromosome"s dna molecule.