NEET BIOLOGY

Detailed explanation-1: -During mitosis (nuclear division), the chromosomes condense, the nuclear envelope of most cells breaks down, the cytoskeleton reorganizes to form the mitotic spindle, and the chromosomes move to opposite poles. Chromosome segregation is then usually followed by cell division (cytokinesis).

Detailed explanation-2: -During prophase, the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down.

Detailed explanation-3: -Prophase is the first step of mitosis, during which chromosomes condense and the nuclear envelope dissolves. Metaphase follows prophase.

Detailed explanation-4: -During prophase, chromatin condenses into chromosomes, and the nuclear envelope, or membrane, breaks down . In animal cells, thecentrioles near the nucleus begin to separate and move to opposite poles (sides) of the cell. As the centrioles move, a spindle starts to form between them.

Detailed explanation-5: -During prophase II, chromosomes condense and the nuclear envelope breaks down, if needed. The centrosomes move apart, the spindle forms between them, and the spindle microtubules begin to capture chromosomes.