NEETBotanyCell Cycle and Cell Division
A cytologist arrests dividing somatic cells at the stage considered most suitable to study the morphology of chromosomes. Which of the following accurately describes the state of the chromosomes at this arrested stage?
Options
- AChromosomes are aligned as bivalents at the equator, with each bivalent consisting of four chromatids.
- BSister chromatids have separated and are moving towards opposite poles of the cell.
- CEach chromosome consists of two sister chromatids held together by a centromere and is aligned at the equatori
- DChromosomal material appears as intertwined threads within an intact nuclear envelope.
Correct answer
C. Each chromosome consists of two sister chromatids held together by a centromere and is aligned at the equatori
Step-by-step solution
The stage most suitable to study the morphology of chromosomes is mitotic metaphase, because by this stage the condensation of chromosomes is completed and they can be observed clearly under the microscope. During mitotic metaphase, each chromosome is made up of two sister chromatids held together by a centromere. These chromosomes are moved to the spindle equator and get aligned along the metaphase plate. The other options describe different stages of cell division: aligning as bivalents occurs in metaphase I of m