Sister Chromatid Pair

∞ generated and posted on 2016.12.22 ∞

Products of DNA replication in eukaryotes as well as what a metaphase chromosome consists of in terms of DNA.

Sister chromatid pairs consist of pairs of double helices, each of which is the daughter of a single double helix as generated during S phase of interphase. During mitosis, prior to metaphase, the sister chromatid pairs condense into individual metaphase chromosomes. During anaphase the sister chromatid pairs separate into individual sister chromatids, each of which can be described as an individual chromosome.

Figure legend: Depiction of metaphase chromosome indicating sister chromatids as well as location of centromere, which also is the site of kinetochore attachment. Chromosome image is based on trace of photograph posted on cytochemistry.net.

It is a good idea to put some effort into understand the difference between as well as similarities among the terms chromatin, double helix, sister chromatid, sister chromatid pair, and chromosome. Being able to properly name the DNA at different points in the cell cycle is one means by which one can assess one's understanding of what is going on during mitosis and meiosis. Note, however, that many of these concepts (though not all!) are limited to describing the nuclear division rather than being also application to prokaryotic, extrachromosomal, or cytoplasmic DNA.


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