Given below is a diagram representing a stage during the mitotic cell division. Study the diagram and answer the following questions: Given below is a diagram representing a stage during the mitotic cell division. Study the diagram and answer the following questions:
Identify the stage by giving a suitable reason.
Topic: Identifying anaphase
Answer
The stage is ANAPHASE.
Reason: the CENTROMERES have split and the two chromatids of each chromosome have SEPARATED and are being drawn by the contracting spindle fibres towards OPPOSITE POLES of the cell.
Give the stage AND the visible reason — the question asks for both, and the reason must describe what can be SEEN in the diagram.
Each stage has one unmistakable feature: PROPHASE — chromosomes visible but scattered; nuclear membrane breaking down METAPHASE — chromosomes LINED UP at the equator in one plane ANAPHASE — chromatids SEPARATED, moving to opposite poles, drawn V or J shaped TELOPHASE — two groups at the poles; nuclear membranes re-forming
THE V OR J SHAPE is itself evidence: the spindle fibre pulls at the CENTROMERE, so the arms of the chromosome trail behind like a towed object.