NEET BIOLOGY

Detailed explanation-1: -Mitotic nondisjunction can cause somatic mosaicism, with the chromosome imbalance only reflected in the direct offspring of the original cell where the nondisjunction occurred. This can cause some forms of cancer, including retinoblastoma.

Detailed explanation-2: -Mutations can result from errors in DNA replication during cell division, exposure to mutagens or a viral infection.

Detailed explanation-3: -During pregnancy, an error in mitosis can occur. If the chromosomes don’t split into equal halves, the new cells can have an extra chromosome (47 total) or have a missing chromosome (45 total).

Detailed explanation-4: -Mistakes during mitosis lead to the production of daughter cells with too many or too few chromosomes, a feature known as aneuploidy. Nearly all aneuploidies that arise due to mistakes in meiosis or during early embryonic development are lethal, with the notable exception of trisomy 21 in humans.

Detailed explanation-5: -Disruption of normal regulation of the cell cycle can lead to diseases such as cancer. When the cell cycle proceeds without control, cells can divide without order and accumulate genetic errors that can lead to a cancerous tumor .