Biology: Homework Help!
Duplication of the chromosomes to produce sister chromatids _____.
A) occurs in meiosis but not in mitosis
B) occurs in mitosis but not in meiosis
C) occurs in both
D) occurs in neither
You are only allowed to ask one question at a time so I edited down accordingly. You are asking about the formation of sister chromatids during the cell cycle. During the S portion of the interphase, the cell replicates its chromosomes in preparation for upcoming separation and cell division. During replication, the chromosomes are replicated to produce an identical copy of each chromosome. The resulting sister chromatids are bound together by centromeres to make the familiar uneven X shape. This precedes both mitosis and meiosis. The difference between the two is that there will be a crossing over of the sister chromatids before meiosis to mix up the chromosome fragments before separation. The crossing over does not occur in mitosis. Also, mitosis contains a single cell separation while meiosis contains two separations. The answer to the question is C.