NEET BIOLOGY

Detailed explanation-1: -Centrioles help in cell division. During prophase they move towards the poles and in metaphase the spindle fibres are formed between centrioles and the centromere of the chromosome.

Detailed explanation-2: -During prophase, the nuclear envelope and nucleolus are dissolved and the chromosomes condense. The centrioles and spindle fibers begin to form at opposite poles of the cell. Chromatid separation is not seen until anaphase.

Detailed explanation-3: -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-4: -Spindle fibers function twice during meiosis. Their role again is to attach to chromosomal structures and pull them apart to opposite ends of the cell. During both meiosis’ prophases, the spindle fibers become visible and then extend from centrosomes and centrioles at opposite ends of the cell during both metaphases.