AP BIOLOGY

Detailed explanation-1: -When the sperm and egg cells unite at conception, each contributes 23 chromosomes so the resulting embryo will have the usual 46. Meiosis also allows genetic variation through a process of gene shuffling while the cells are dividing.

Detailed explanation-2: -Egg and sperm cells each have 23 chromosomes (one-half of the chromosomes of other cells) and arise from specialized cells called germ cells. However, before a germ cell splits, each chromosome exchanges a piece of itself with its partner chromosome in a process called “crossover, ” or recombination.

Detailed explanation-3: -Chromosomes come in pairs. 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.

Detailed explanation-4: -*except sperm cells and egg cells in the ovaries which are “haploid” and have 23 chromosomes (with the 23rd being an X in the eggs, and either an X or a Y in the sperm), and not 46 “diploid” like other cells.

Detailed explanation-5: -The 23rd pair of chromosomes are two special chromosomes, X and Y, that determine our sex. Females have a pair of X chromosomes (46, XX), whereas males have one X and one Y chromosomes (46, XY). Chromosomes are made of DNA, and genes are special units of chromosomal DNA.