AP BIOLOGY

Detailed explanation-1: -Sex cells are different from other cells in one special way: Put simply, they only have one half of the total amount of human genetic information. When a sperm cell fertilizes an egg cell, the resulting cell has a full set of genetic information again.

Detailed explanation-2: -Sex cells have one set of chromosomes; body cells have two. Offspring arise from the union of specialized sex cells — a female egg and a male sperm. In sexual reproduction, offspring arise from the union of specialized sex cells — a female egg and a male sperm.

Detailed explanation-3: -If sex cells, like sperm and egg, have the same number of chromosomes as regular body cells, then each time they combined, the progeny would have twice the number of chromosomes. This doesn’t happen. So, there must be a process that halves chromosome number in sex cells.

Detailed explanation-4: -Gametes are reproductive cells, such as sperm and egg. As gametes are produced, the number of chromosomes must be reduced by half. Why? The zygote must contain genetic information from the mother and from the father, so the gametes must contain half of the chromosomes found in normal body cells.

Detailed explanation-5: -Egg and sperm cells have just 23 chromosomes each. That’s half as many chromosomes as regular cells. Through the process of fertilization, egg and sperm join to make a cell with 46 chromosomes (23 pairs), called a zygote. For each chromosome pair, one homologous chromosome came from each parent.