Chapters 11 & 12

Question 1

An observable heritable feature that may vary among individuals

Answer 1

Character

Question 2

One of two or more detectable variants in a genetic character

Answer 2

Trait

Question 3

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

Answer 3

Law of Segregation

Question 4

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 4

Law of Independent Assortment

Question 5

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

Answer 5

Genotype

Question 6

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

Answer 6

Phenotype

Question 7

Having two identical alleles for a given gene

Answer 7

Homozygous

Question 8

Having two different alleles for a given gene.

Answer 8

Heterozygous

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

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

Answer 11

Complete Dominance

Question 12

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

Answer 12

Incomplete dominance

Question 13

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

Answer 13

Codominance

Question 14

The ability of a single gene to have multiple effects.

Answer 14

Pleiotropy

Question 15

An allele of a genetic locus having more than two allelic forms within a population

Answer 15

Multiple Alleles

Question 16

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

Answer 16

Epistatis

Question 17

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

Answer 17

Polygenic Inheritance

Question 18

Breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of phenotypes in the offspring reveals the unknown genotype.

Answer 18

Testcross

Question 19

An organism that is heterozygous with respect to a single gene of interest. All the offspring from a cross between parents homozygous for different alleles have this trait.

Answer 19

Monohybrid

Question 20

A cross between two organisms that are each heterozygous for both of the characters being followed

Answer 20

Dihybrid Cross

Question 21

The phenotype most commonly observed in natural populations; also refers to the individual with that phenotype

Answer 21

Wild Type

Question 22

A change in the DNA sequence of an organism

Answer 22

Mutant

Question 23

One of the numbered chromosomes that is not a sex chromosome.

Answer 23

Autosome

Question 24

A type of chromosome involved in sex determination.

Answer 24

Sex Chromosome

Question 25

A gene located on either sex chromosome. Most sex-linked genes are on the X chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosome.

Answer 25

Sex-linked Genes

Question 26

A gene located on the X chromosome; such genes show a distinctive pattern of inheritance.

Answer 26

X-linked Genes

Question 27

A process by which one of the copies of the X chromosome is inactivated in therian female mammals.

Answer 27

X inactivation

Question 28

Genes located close enough together on a chromosome that they tend to be inherited together.

Answer 28

Linked Genes

Question 29

An ordered list of genetic loci (genes or other genetic markers) along a chromosome.

Answer 29

Genetic Map

Question 30

An error in meiosis or mitosis in which members of a pair of homologous chromosomes or sister chromatids fail to separate properly from each other.

Answer 30

Nondisjunction

Question 31

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.

Answer 31

Aneuploidy

Question 32

A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division.

Answer 32

Polyploidy

Question 33

Referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two.

Answer 33

Monosomic

Question 34

Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two.

Answer 34

Trisomic