Chapter 6

Front 1

somatic cells

Back 1

cell that makes up all the body tissues and organs, except gametes

Front 2

gamete

Back 2

sex cell; an egg or sperm cellhom

Front 3

homologous chromosome

Back 3

chromosomes that have the same length, appearance, and copies of genes, although the alleles may differ

Front 4

autosome

Back 4

chromosome that contains genes for characteristics not directly related to the sex of the organism

Front 5

sex chromosome

Back 5

chromosomes that directly controls the development if sexual characteristics

Front 6

sexual reproduction

Back 6

process by which two gametes fuze and offspring that are a genetic mixture of both parents are produced

Front 7

fertilization

Back 7

fusion of an egg and sperm cell

Front 8

diploid

Back 8

cell that has two copies of each chromosome, one from an egg and one from a sperm

Front 9

haploid

Back 9

cell that has only one copy of each chromosome

Front 10

meiosis

Back 10

form of nuclear division that divides a diploid cell into haploid cells; important in forming gametes for sexual reproduction

Front 11

gametogenesis

Back 11

process by which gametes are produced through the combination of meiosis and other maturational changes

Front 12

sperm

Back 12

male gamete

Front 13

egg

Back 13

female gamete

Front 14

polar body

Back 14

haploid cell produced during meiosis in the female of many species; these cells have little more than DNA and eventually disintegrate

Front 15

trait

Back 15

characteristic that is inherited

Front 16

genetics

Back 16

study of the heredity pattern ls and variation of organisms

Front 17

purebred

Back 17

type of organism whose ancestors are genetically uniform

Front 18

cross

Back 18

mating of two organisms

Front 19

law of segregation

Back 19

Mendel's first law, stating that (1) organisms inherit two copies of genes, one from each parent, and (2) because organisms donate only one copy of each gene in their gametes because the genes separate during gamete formation

Front 20

gene

Back 20

specific region of DNA that codes for a particular protein

Front 21

allele

Back 21

any of the alternative forms of a gene that occurs at a specific place on a chromosome

Front 22

homozygous

Back 22

characteristic of having two of the same alleles at the same locus of sister chromatids

Front 23

heterozygous

Back 23

characteristic of having two different alleles that appear at the same locus of sister chromatids

Front 24

genome

Back 24

all of an organism's genetic material

Front 25

genome

Back 25

all of an organism's genetic material

Front 26

genotype

Back 26

collection of all of an organism's genetic information that codes for traits

Front 27

phenotype

Back 27

collection of all of an organism's physical characteristics

Front 28

phenotype

Back 28

collection of all of an organism's physical characteristics

Front 29

dominant

Back 29

allele that is expressed when two different alleles ate present in an organism's genotype

Front 30

recessive

Back 30

allele that is not expressed unless two copies are present in an organism's genotype

Front 31

Punnett square

Back 31

model for predicting all possible genotypes resulting from a cross, or mating

Front 32

Punnett square

Back 32

model for predicting all possible genotypes resulting from a cross, or mating

Front 33

monohybrid cross

Back 33

cross, or mating, between organisms that involves only one pair of contrasting traits

Front 34

Punnett square

Back 34

model for predicting all possible genotypes resulting from a cross, or mating

Front 35

monohybrid cross

Back 35

cross, or mating, between organisms that involves only one pair of contrasting traits

Front 36

testcross

Back 36

cross between an organism with an unknown genotype and an organism with a recessive phenotype

Front 37

dihybrid cross

Back 37

cross, or mating, between organisms involving two pairs of contrasting traits

Front 38

dihybrid cross

Back 38

cross, or mating, between organisms involving two pairs of contrasting traits

Front 39

law of independent assortment

Back 39

Mendel's second law, stating that allele pairs seperate from one another during gamete formation

Front 40

probability

Back 40

likelihood that a particular event will happen

Front 41

crossing over

Back 41

exchange of chromosome segments between homologous chromosomes during meiosis I

Front 42

crossing over

Back 42

exchange of chromosome segments between homologous chromosomes during meiosis I

Front 43

genetic linkage

Back 43

tendency for genes located close together on the same chromosome to be inherited together

Front 44

crossing over

Back 44

exchange of chromosome segments between homologous chromosomes during meiosis I

Front 45

genetic linkage

Back 45

tendency for genes located close together on the same chromosome to be inherited together