Chapter 9

Question 0

Genetically determined classes of human blood that are based on the presence or absence of carbohydrates A and B on the surface of red blood cells. The ABO blood group phenotypes, also called blood types, are A, B, AB, and O.

Answer 0

ABO Blood Groups.

Question 1

A form of human dwarfism caused by a single dominant allele; the homozygous condition is lethal.

Answer 1

Achondroplasia.

Question 2

An alternative version of a gene.

Answer 2

Allele.

Question 3

A technique for diagnosing genetic defects while a fetus is in the uterus. A sample of amniotic fluid, obtained by a needle inserted into the amnion, is analyzed for telltale chemicals and defective fetal cells.

Answer 3

Amniocentesis.

Question 4

An individual who is heterozygous for a recessively inherited disorder and who therefore does not show symptoms of that disorder but who may pass on the recessive allele to offspring.

Answer 4

Carrier.

Question 5

A heritable feature that varies among individuals within a population, such as flower color in pea plants.

Answer 5

Character.

Question 6

A technique for diagnosing genetic defects while the fetus is in an early development stage within the uterus. A small sample of the fetal portion of the placenta is removed and analyzed.

Answer 6

Chorionic Villus Sampling (CVS).

Question 7

A basic principle in biology stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns.

Answer 7

Chromosome Theory of Inheritance.

Question 8

Inheritance pattern in which a heterozygote expresses the distinct trait of both alleles.

Answer 8

Codominant.

Question 9

A type of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable.

Answer 9

Complete Dominance.

Question 10

A mating of two sexually reproducing individuals; often used to describe a genetics experiment involving a controlled mating.

Answer 10

Cross.

Question 11

The fusion of sperm and egg derived from two different individuals.

Answer 11

Cross-Fertilization.

Question 12

A genetic disease that occurs in people with two copies of a certain recessive allele; characterized by an excessive secretion of mucus and vulnerability to infection; fatal if untreated.

Answer 12

Cystic Fibrosis.

Question 13

An experimental mating of individuals differing at two genetic loci.

Answer 13

Dihybrid Cross.

Question 14

The allele that determines the phenotype of a gene when the individual is heterozygous for that gene.

Answer 14

Dominant Allele.

Question 15

A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue.

Answer 15

Duchenne Muscular Dystrophy.

Question 16

The offspring of two parental (P generation) individuals; F1 stands for first filial.

Answer 16

F1 Generation

Question 17

The offspring of the F1 generation; F2 stands for second filial.

Answer 17

F2 Generation

Question 18

The genetic makeup of an organism.

Answer 18

Genotype.

Question 19

A human genetic disease caused by a sex-linked recessive allele; characterized by excessive bleeding following injury.

Answer 19

Hemophilia.

Question 20

Having two different alleles for a given gene.

Answer 20

Heterozygous.

Question 21

Having two identical alleles for a given gene.

Answer 21

Homozygous.

Question 22

A human genetic disease caused by a dominant allele; characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10-20 years after the onset of symptoms.

Answer 22

Huntington’s Disease.

Question 23

The offspring of parents of two different species or of two different varieties of one species; the offspring of two parents that differ in one or more inherited traits; an individual that is heterozygous for one or more pairs of genes.

Answer 23

Hybrid.