Biology Ch 8 Test

Front 1

dominant

Back 1

expressed form of the character

Front 2

recessive

Back 2

the trait that was not expressed when the dominant form of the character was present

Front 3

homozygous

Back 3

describes an individual that has identical alleles for a trait on both omologous chromosomes

Front 4

heterozygous

Back 4

describes an individual that has two different alleles for a trait

Front 5

genotype

Back 5

the entire genetic makeup of an organism; also the combination of genes for one or more specific traits

Front 6

phenotype

Back 6

an organism's appearance or other detectable characteristic that results from the organism's genotype and the environment

Front 7

law of segregation

Back 7

Mende's law that states that the pairs of homologous chromosomes separate in meiosis so that only one hromosome from each pair is present in each gamate

Front 8

law of independent assortment

Back 8

the law that states that genes separate independently of one another in meiosis

Front 9

heredity

Back 9

the passing of genetic traits from parent to offspring

Front 10

genetics

Back 10

the science of heredity and of the mechanisms by which traits are passed from parents to offspring

Front 11

monohybrid cross

Back 11

a cross between individuals that involves one pair of contrasting traits

Front 12

true-breeding

Back 12

describes organisms or genotypes that are homozygous for a specific trait and thus always produce offspring that have the same phenotype for that trait

Front 13

P generation

Back 13

parental generation, the first two individuals that mate in a genetic cross

Front 14

F1 generation

Back 14

the first generation of offspring obtained from an experimental cross of two organisms

Front 15

F2 generation

Back 15

the second generation of offspring, obtained from an experimental cross of two organisms; the offspring of the F1 generation

Front 16

allele

Back 16

one of the alternative forms of a gene that governs a characteristic, such as hair color

Front 17

test cross

Back 17

the crossing of an inidvidual of unknown genotype with a homozygous recessive individual to determine the unknown genotype

Front 18

pedigree

Back 18

a diagram that shows the occurence of a genetic train in several generations of a family

Front 19

sex-linked gene

Back 19

located only on the x or y chromosome

Front 20

polygenic inheritance

Back 20

when several genes influence a character

Front 21

multiple alleles

Back 21

more than two alleles (versions of the gene) for a genetic trait

Front 22

codominance

Back 22

a condition in which both alleles for a gene are fully expressed