How are chromatids, chromatin and chromosomes related

Two chromatid chromosome

Under a Two chromatid chromosome one understands a chromosome, which is made up of two identical longitudinal elements, the two chromatids, more precisely: the sister chromatids. From a chemical point of view, the chromatids consist of DNA and associated proteins (histones) and are attached to one another at a connection point, the centromere.

The two sister chromatids that make up the two-chromatid chromosome can be clearly identified with the aid of a light microscope during the metaphase of mitosis or meiosis. Hence one speaks of a Metaphase chromosomeif you mean a two-chromatid chromosome.

Two chromatid chromosome

  1. Chromatid or Chromatide (blue). One of the two identical parts of the two-chromatid chromosome, consisting of a multi-spiraled DNA thread together with the associated core proteins.
  2. Centromere (red). The point at which the two chromatids in the two-chromatid chromosome are attached to each other.
  3. Short arm. (p-arm)
  4. Long arm. (q-arm)

In the course of the division process, both in mitosis and in meiosis, the two chromatids of each two-chromatid chromosome are separated from each other on the centromere, so that two one-chromatid chromosomes are created, which are drawn by the spindle apparatus to the cell poles. Two daughter cells are obtained, each with identical one-chromatid chromosomes, which double their DNA during the interphase, so that two-chromatid chromosomes are again present at the beginning of a new division phase.

Categories: Genetics | Cell biology