Unformatted text preview: First, (as you've said) each human cell has 46 chromosomes . After synthesis (S phase), each of these chromosomes will be composed of 2 sister chromatids. Therefore, there are 96 chromatids in a somatic cell after S phase. Now, although you may say there are 96 sister chromatids, you still have 46 chromosomes (or 46 duplicated chromosomes...46*2=96). If you say that a human cell has 96 chromosomes, you are also implying that it is no longer a diploid but now somehow a tetraploid. But in a normal cell, it can only be a diploid (somatic cell) or haploid (in gametes) state. Okay, so the book is right in saying that each cell has 1 chromatin after mitosis because during anaphase, all 46 duplicated chromosomes (sister chromatids) get separated into nonduplicated chromosomes or chromatids. So you still have a whole chromosome (or also called a chromatid). IN MEIOSIS: Anaphase I, 23 homologous pairs separate (so essentially 23 duplicated chromosome to one pole and 23 duplicated chromosomes to the other pole)....
View Full Document
This note was uploaded on 01/09/2009 for the course BILD BILD 1 taught by Professor Bever during the Spring '08 term at UCSD.
- Spring '08