Q.While observing a slide, student observed many cells with nuclei. But some of the nuclei were bigger as compared to others but their nuclear membrane was not so clear. Teacher inferred it as one of the phase in the cell division. Which phase may be inferred by teacher?

Mitosis is the equational nuclear division in which the daughter cells end up with exactly the same chromosome number as the parent cell, making it responsible for growth, tissue repair and asexual reproduction. In plants it occurs mainly in meristematic tissue (shoot and root tips); it can be closed (spindle forms inside an intact nuclear envelope, as in yeasts and slime moulds) or open (the nuclear envelope breaks down and later re-forms, as in most plants and animals). Mitosis proceeds through four phases. In prophase, chromosomes condense into visible mitotic chromosomes, the nuclear envelope breaks down, and in animal cells the centrioles organise an aster of microtubules at each pole (plant cells, lacking centrioles, do not form asters). In metaphase, chromosomes attach to spindle fibres via their kinetochores and align at the equatorial metaphase plate, checked by the spindle assembly checkpoint. In anaphase, the enzyme complex APC/C degrades cohesin, each centromere splits, and sister chromatids are pulled to opposite poles. In telophase, the spindle disappears, nuclear …