AP BIOLOGY

Detailed explanation-1: -The mother gives an X chromosome to the child. The father may contribute an X or a Y. The chromosome from the father determines if the baby is born as male or female. The remaining chromosomes are called autosomal chromosomes.

Detailed explanation-2: -The sex chromosomes determine the sex of offspring. The father can contribute an X or a Y chromosome, while the mother always contributes an X. The Y chromosome is one-third the size of the X chromosome and contains about 55 genes while the X chromosome has about 900 genes.

Detailed explanation-3: -Males with XYY syndrome have 47 chromosomes because of the extra Y chromosome. This condition is also sometimes called Jacob’s syndrome, XYY karyotype, or YY syndrome.

Detailed explanation-4: -Sex chromosomes usually determine whether you are female or male. Women are XX. Men are XY. However, genetically, a few women are actually men.

Detailed explanation-5: -In humans, sex is determined by sex chromosomes (XX females, XY males). The X and Y chromosomes harbor dramatically different numbers and sets of genes (about 1, 000 genes on the X and only a few dozen genes on the Y), yet they originated from ordinary autosomes during the early evolution of mammals (Figure 1).