Question

define chromatid in easy words, it's chaper-5 cell of class 9​

Answer 1

Answer:

Chromatid in easiest words is nothing but a collection of a long string of DNA (a long helically placed molecule you must've seen pictures of) in a certain pattern to compact into a smaller structure. Some may argue this is the definition of a chromosome, but it isn't that different.

Explanation:

During cell division, each of the organelles have to be duplicated in order to be given to each of the cell. For the same reason, DNA material is also duplicated. And as mentioned above, it is really compacted (2.2 metres of DNA is present in cell nucleus of 10 × 10⁻⁶ meter). So for division it, in that compacted state only duplicates itself and forms that 'X' shaped figure you must've seen diagrams of. So from an 'I' with a constriction (the centrosome) in the middle, it forms an 'X'. Now both arms of that 'X' are exact copies of each other and would be given to each cell later. Each of these arms are called chromatid. These can be sister or non-sister chromatid, but that is something you will study about later.

Both in the 'I' form, or the 'X'  form, it is called a chromosome only. Just the different arms in the 'X' form are called chromatids.

Thank you!

Answer 2

Answer:

one of the usually paired and parallel strands of a duplicated chromosome joined by a single centromere........