There are approximately ______________ in humans. a. 500 to 1,000 genes b. 10,000 to 15,000 genes c. 19,000 to 25,000 genes d. 100,000 to 125,000 genes

About this percent of the DNA carries active genes. a. 2% b. 15% c. 22% d. 38%

The shorter arm of the chromosome coming from the centromere is called the a. q-arm. b. p-arm. c. t-arm. d. s-arm.

Which of the following increases genetic variation in the offspring? a. Mitosis b. Independent assortment c. Crossing-over d. Both B and C are correct.

The normal skin pigment gene "A" is dominant to the recessive albino gene "a." A person with genes Aa a. would be albino. b. would have normal skin pigment. c. would be considered a carrier for albinism. d. Both B and C are correct.

Which of the following is not true about the X and Y chromosomes? a. The X chromosome is larger than the Y chromosome. b. The male determines the sex of the offspring. c. Almost all of the sex-linked traits are carried on the Y chromosome. d. All of the above are true of the X and Y chromosomes.

This is an example of a sex-linked condition. a. Albinism b. Red-green color blindness c. Sickle cell anemia d. Down syndrome

The single-gene disease caused by recessive genes that fail to produce the enzyme phenylalanine hydroxylase is a. phenylketonuria. b. cystic fibrosis. c. Tay-Sachs disease. d. Down syndrome

The most well-known chromosomal disorder is trisomy 21, which produces a group of symptoms called a. Down syndrome. b. Turner syndrome. c. Klinefelter syndrome. d. Tay-Sachs disease.

A chart that illustrates genetic relationships in a family over several generations is called a a. karyotype. b. Punnett square. c. pedigree. d. ideogram

The procedure in which fetal tissue can be collected from the fluid surrounding the fetus is called a. chorionic villus sampling. b. ultrasound. c. echogram. d. amniocentesis.

Which of the following is not true of genetic mutations? a. They are a change in the genetic code. b. They can be caused by chemicals or radiation. c. They are always harmful to the cell or individual. d. All of the above are true of genetic mutations.

This is the science that describes how environmental factors may result in offspring with genetic traits that cannot be explained by genes alone. a. Epigenetics b. Genomics c. Pseudogenetics d. Proteomics

This is a single-gene disease that causes an impairment of ion transport across the cell membrane. a. Phenylketonuria b. Cystic fibrosis c. Tay-Sachs disease d. Fragile X syndrome

This is a single-gene recessive condition that involves the failure of an essential lipid- processing enzyme, hexosaminidase. a. Phenylketonuria b. Cystic fibrosis c. Tay-Sachs disease d. Fragile X syndrome

This is an epigenetic condition caused by an overmethylation of a section of DNA. a. Phenylketonuria b. Cystic fibrosis c. Tay-Sachs disease d. Fragile X syndrome

This condition is caused by a male having an extra X chromosome, XXY. a. Down syndrome b. Klinefelter syndrome c. Turner syndrome d. Fragile X syndrome

This condition occurs in a female with a single X chromosome, XO. a. Down syndrome b. Klinefelter syndrome c. Turner syndrome d. Fragile X syndrome

This is a grid that is used to determine the probability of inheriting a genetic trait. a. A pedigree b. A Punnett square c. A karyotype d. An ideogram

This can be used to detect chromosome disorders by studying photographs of chromosomes in the process of mitosis. a. A pedigree b. A Punnett square c. A karyotype d. An ideogram