Chapter 14

Question 1

An observable heritable feature.

Answer 1

Character

Question 2

Any detectable variant in a genetic character.

Answer 2

Trait

Question 3

Referring to plants that produce offspring of the same variety when they self-pollinate.

Answer 3

True-Breeding

Question 4

In genetics, the mating, or crossing, of two true-breeding varieties.

Answer 4

Hybridization

Question 5

Any of the alternative versions of a gene that produce distinguishable phenotypic effects.

Answer 5

Alleles

Question 6

Mendel’s first law, stating that the two alleles in a pair segregate (separate) into different gametes during gamete formation.

Answer 6

Law of Segregation

Question 7

Mendel’s second law, stating that each pair of alleles segregates, or assorts, independently of each other pair during gamete formation; applies when genes for two characters are located on different pairs of homologous chromosomes.

Answer 7

Law of Independent Assortment

Question 8

A diagram used in the study of inheritance to show the predicted results of random fertilization in genetic crosses.

Answer 8

Punnett Square

Question 9

An allele that is fully expressed in the phenotype of a heterozygote.

Answer 9

Dominant Allele

Question 10

An allele whose phenotypic effect is not observed in a heterozygote.

Answer 10

Recessive Allele

Question 11

Having two different alleles for a given gene.

Answer 11

Heterozygous

Question 12

Having two identical alleles for a given gene.

Answer 12

Homozygous

Question 13

The genetic makeup, or set of alleles, of an organism.

Answer 13

Genotype

Question 14

The physical and physiological traits of an organism, which are determined by its genetic makeup.

Answer 14

Phenotype

Question 15

The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable.

Answer 15

Complete Dominance

Question 16

The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele.

Answer 16

Incomplete Dominance

Question 17

The situation in which the phenotypes of both alleles are exhibited in the heterozygote because both of the alleles affect the phenotype in separate, distinguishable ways.

Answer 17

Codominance

Question 18

A human genetic disease caused by a recessive allele for a dysfunctional enzyme, leading to accumulation of certain lipids in the brain.

Answer 18

Tay Sachs Disease

Question 19

A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited.

Answer 19

Epistasis

Question 20

The ability of a single gene to have multiple effects.

Answer 20

Pleiotropy

Question 21

An additive effect of two or more genes on a single phenotypic character.

Answer 21

Polygenic Inheritance

Question 22

Referring to a phenotypic character that is influenced by multiple genes and environmental factors.

Answer 22

Multifactorial

Question 23

A diagram of a family tree showing the occurrence of heritable characters in parents and offspring over multiple generations.

Answer 23

Pedigree

Question 24

In genetics, an individual who is heterozygous at a given genetic locus, with one normal allele and one recessive allele.

Answer 24

Carriers

Question 25

A human genetic disorder caused by a recessive allele for a chloride channel protein; characterized by an excessive secretion of muss and consequent vulnerability to infection; fatal if untreated.

Answer 25

Cystic Fibrosis

Question 26

A juan genetic disease caused by a recessive allele that results in the substitution of a single amino acid in a globin polypeptide that is part of the hemoglobin protein; characterized by deformed red blood cells (due to protein aggregation) that can lead to numerous symptoms.

Answer 26

Sickle Cell Disease

Question 27

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

Answer 27

Huntington’s Disease

Question 28

A technique of prenatal diagnosis in which amniotic fluid, obtained by aspiration from a needle inserted into the uterus, is analyzed to detect certain genetic and congenital defects in the fetus.

Answer 28

Amniocentesis

Question 29

A technique of prenatal diagnosis in which a small sample of the fetal portion of the placenta is removed and analyzed to detect certain genetic and congenital defects in the fetus.

Answer 29

Chorionic Villus Sampling