A chromatid is one of two identical strands of DNA making up a
chromosome that are joined at their
centromeres, for the process of nuclear division (
mitosis or
meiosis). The term is used so long as the centromeres remain in contact. When they separate (during
anaphase of mitosis and anaphase 2 of meiosis), the strands are called daughter-chromosomes.The tips of the chromatid are called
telomeres.They are there to prevent the ends of the chromosome from attaching to other chromosomes. It has been said that after repeated cell replication, the telomeres gets shorter resulting in cell death. This means that the way telomeres work could determine the lifespan of a cell. However this has not been proven.
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One of two copies of a replicated chromosome during mitosis. Together they are called sister chromatids. Each one becomes a daughter chromosome at anaphase of mitosis and at the second meiotic division.