NEET BIOLOGY

Detailed explanation-1: -Normally, each cell in the human body has 23 pairs of chromosomes (46 total chromosomes). Half come from the mother; the other half come from the father. Two of the chromosomes (the X and the Y chromosome) determine your sex as male or female when you are born.

Detailed explanation-2: -In meiosis, a cell containing the diploid number of chromosomes is converted into four cells, each having the haploid number of chromosomes. In human cells undergoing meiosis, for instance, a cell containing 46 chromosomes yields four cells, each with 23 chromosomes.

Detailed explanation-3: -We inherit a set of 23 chromosomes from our mothers and another set of 23 from our fathers. One of those pairs are the chromosomes that determine the biological sex of a child – girls have an XX pair and boys have an XY pair, with very rare exceptions in certain disorders.

Detailed explanation-4: -Healthy humans have 46 chromosomes, 23 from the sperm and 23 from the egg. An embryo with the wrong number of chromosomes is usually miscarried, or develops disorders such as Down’s syndrome, which is caused by an extra copy of chromosome 21.

Detailed explanation-5: -When a woman becomes pregnant, her egg joins with the father’s sperm to make a new cell. This cell will grow and divide into a baby. This first cell has 46 chromosomes, 23 from the mother and 23 from the father. All the instructions for how the child will grow are in the genes on these chromosomes.