Biology / Unit 4 Bio 0849 short lesson, about 20 seconds
S Phase
Captions available
The idea
S phase, the synthesis stage of interphase, is when a cell replicates its chromosomal DNA, producing sister chromatids, and also duplicates its centrosome.
In practice
Each chromosome entering S phase as a single DNA molecule exits as two sister chromatids joined at the centromere.
Where people slip
S phase copies chromosomes but does not yet separate or fully condense them — that comes later, in mitosis.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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