Biology

Answer to question # 1

XO: Turner syndrome is caused by a missing or incomplete X chromosome. Turner syndrome affects growth and sexual development. Girls with this disorder are shorter than normal, and may fail to start puberty when they should. This is because the ovaries fail to develop properly. Women with Turner syndrome appear to have a stocky appearance, arms that turn out slightly at the elbow, a receding lower jaw, a short webbed neck, and low hairline at the back of the neck. Other medical symptoms include: lymphedema (swelling of hands and feet), heart and/or kidney defects, high blood pressure, and infertility (inability to have children).

XXY: Klinefelter syndrome is a condition in which human males have an extra X chromosome. People with this disorder are often tall and usually don't develop secondary sex characteristics, such as facial hair or underarm and pubic hair. The extra X chromosome primarily affects the testes, which produce sperm and the male hormone testosterone.

XYY: Jacobs syndrome is a rare chromosomal genetic syndrome where the male person has an extra Y male chromosome, becoming XYY instead of normal XY (male) or XX (female). It typically causes no unusual physical features or medical problems. Persons with this syndrome may be slightly taller than average, or have more severe acne than normal. Most males with XYY syndrome have normal sexual development and are able to conceive children.

XXX: Triple X syndrome is characterized by the presence of an additional X chromosome in each of a female's cells. Although females with this condition may be taller than average, this chromosomal change typically causes no unusual physical features. Most females with triple X syndrome have normal sexual development and are able to conceive children.

Answer to question # 3

A. A a

a Aa aa

a Aa aa

Genotype: 2:2

Phenotype: 2:2

B.

B

B

b Bb Bb

b Bb Bb

Genotype: all Bb

Phenotype: all have dominant characteristic...