Chapter 5 - Vocabulary

Question 1

Additive Allele

Answer 1

an allele that has a partial influence on a phenotype.

Question 2

Allele

Answer 2

a specific form of a gene.

Question 3

Autosomal Inheritance

Answer 3

inheritance of alleles located on autosomal (non-sex) chromosomes.

Question 4

Carrier Testing

Answer 4

a genetic test that determines whether an individual is heterozygous for a given gene that results in a genetic disorder.

Question 5

Codominance

Answer 5

a situation where both alleles are expressed fully to produce offspring with a third phenotype.

Question 6

Complete Dominance

Answer 6

a situation where an allele will determine the phenotype, regardless of the presence of another allele.

Question 7

Continuous Variation

Answer 7

when the product of one gene is affected by the product of another gene, the gene products may be additive, or one product may negate another product.

Question 8

Cross

Answer 8

the successful mating of two organisms from distinct genetic lines.

Question 9

Dihybrid Cross

Answer 9

a cross that involves two genes, each consisting of heterozygous alleles.

Question 10

Discontinuous Variation

Answer 10

when the expression of the products of one gene has no bearing on the expression of the products of a second gene.

Question 11

Dominant Allele

Answer 11

the allele that, if present, is always expressed.

Question 12

F1 Generation

Answer 12

the offspring of a P-generation cross

Question 13

F2 Generation

Answer 13

offspring of an F1-generation cross.

Question 14

Genetic Screening

Answer 14

tests used to identify the presence of a defective allele that leads to a genetic disorder.

Question 15

Genotype

Answer 15

the genetic makeup of an individual/

Question 16

Heterozygous

Answer 16

describes an individual that carries two different alleles for a given characteristic.

Question 17

Homozygous

Answer 17

describes an individual that carries two of the same alleles for a given characteristic.

Question 18

Hybrid

Answer 18

the offspring of two different true-breeding plants.

Question 19

Incomplete Dominance

Answer 19

a situation where neither allele dominates the other and both have an influence on the individual; results in partial expression of both traits.

Question 20

Law of Independent Assortment

Answer 20

if genes are located on separate chromosomes, they will be inherited independently of one another.

Question 21

Law of Segregation

Answer 21

a scientific law stating that (1) organisms inherit two copies of genes, one from each parent, and (2) organisms donate only one copy of each gene to their gametes because the genes separate during gamete formation.

Question 22

Monohybrid

Answer 22

the offspring of two different true-breeding plants that differ in only one characteristic.

Question 23

Monohybrid Cross

Answer 23

a cross designed to study the inheritance of only one trait.

Question 24

Mutation

Answer 24

a change in the genetic code of an allele; the change may have a positive effect, a negative effect, or no effect.

Question 25

Pedigree

Answer 25

a diagram of an individual’s ancestors used in human genetics to analyze Mendelian inheritance of a certain trait; also used for selective breeding of plants and animals.

Question 26

P Generation

Answer 26

the parent plants used in a cross.

Question 27

Punnett Square

Answer 27

a diagram that summarizes every possible combination of each allele from each parent; a tool for determining the probability of a single offspring having a particular genotype.

Question 28

Phenotype

Answer 28

an individual’s outward appearance with respect to a specific characteristic.

Question 29

Phenylketonuria (PKU)

Answer 29

an autosomal, recessive, inherited genetic disorder that results in the accumulation of phenylalanine in the tissues and blood.

Question 30

Probability

Answer 30

the likelihood that an outcome will occur if it is a matter of chance.

Question 31

Product Law

Answer 31

the probability of two independent random events both occurring is the product of the individual probabilities of the events.

Question 32

Recessive Allele

Answer 32

the allele that is expressed only if it is not in the presence of the dominant allele, that is, if the individual is homozygous for the recessive allele.

Question 33

Sex-Linked

Answer 33

describes an allele that is found on one of the sex chromosomes, X or Y, and when passed on to offspring is expressed.

Question 34

Test Cross

Answer 34

a cross used to determine the genotype of an individual expressing a dominant trait.

Question 35

Trait

Answer 35

a particular version of a characteristic that is inherited, such as hair colour or blood type.

Question 36

True-Breeding Organism

Answer 36

an organism that produces offspring that are genetically identical for one or more traits when self-pollinated or when crossed with another true-breeding organism for the same traits.

Question 37

X-Linked

Answer 37

phenotypic expression of an allele that is found on the X chromosome.

Question 38

Y-Linked

Answer 38

phenotypic expression of an allele that is found on the Y chromosome.