Sister chromatids

$A)$ Cross over during prophase I of meiosis

$B)$ separate during the first mitotic division

$C)$ are produced during $S$ phase between cell divisions

$D)$ cross over during prophase II of meiosis

$E)$ are also called homologous chromosomes

My thoughts:

  • $A$ is incorrect because it's nonsister chromatids that cross over
  • $B$ is incorrect because they separate during the second mitotic division
  • Don't know about choice $C$
  • $D$ is incorrect because there is no crossing over during Meiosis II
  • $E$ is incorrect because well...it's just not true

So is the answer $C$?


It is C. During S-phase the DNA of each chromosome duplicate and the two sister chromatids formed get attached by cohesin proteins. These sister chromatids separate at Anaphase-II of Meiosis.

From wikipedia:

A sister chromatid refers to either of the two identical copies (chromatids) formed by the replication of a single chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said as 'one-half' of the duplicated chromosome. A full set of sister chromatids is created during the synthesis (S) phase of interphase, when all the chromosomes in a cell are replicated.


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