Chapter 12

Question 1

scientific study of heredity

Answer 1

Genetics

Question 2

process in sexual reproduction in which male and female reproductive cells join to form a new cell

Answer 2

Fertilization

Question 3

specific characteristic of an individual

Answer 3

Trait

Question 4

offspring of crosses between parents with different traits

Answer 4

Hybrids

Question 5

sequence of DNA that codes for a protein and thus determines a trait; factor that is passed from parent to offspring

Answer 5

Gene

Question 6

one of a number of different forms of a gene

Answer 6

Allele

Question 7

Mendel’s second conclusion, which states that some alleles are dominant and others are recessive

Answer 7

Principle of dominance

Question 8

separation of alleles during gamete formation

Answer 8

Segregation

Question 9

sex cell

Answer 9

Gametes

Question 10

likelihood that a particular event will occur

Answer 10

Probability

Question 11

having two identical alleles for a particular gene

Answer 11

Homozygous

Question 12

having two different alleles for a particular gene

Answer 12

Heterozygous

Question 13

physical characteristics of an organism

Answer 13

Phenotype

Question 14

genetic makeup of an organism

Answer 14

Genotype

Question 15

diagram that can be used to predict the genotype and phenotype combinations of a genetic cross

Answer 15

Punnett Square

Question 16

one of Mendel’s principles that states that genes for different traits can segregate independently during the formation of gametes

Answer 16

Independent assortment

Question 17

situation in which one allele is not completely dominant over another allele

Answer 17

Incomplete Dominance

Question 18

situation in which the phenotypes produced by both alleles are completely expressed

Answer 18

Codominance

Question 19

a gene that has more than two alleles

Answer 19

Multiple Alleles

Question 20

trait controlled by two or more genes

Answer 20

Polygenic traits

Question 21

term used to refer to chromosomes in which one set comes from the male parent and one set comes from the female parent

Answer 21

Homologous

Question 22

term used to refer to a cell that contains two sets of homologous chromosomes

Answer 22

Diploid

Question 23

term used to refer to a cell that contains only a single set of genes

Answer 23

Haploid

Question 24

process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

Answer 24

Meiosis

Question 25

structure containing four chromatids that forms during meiosis

Answer 25

Tetrad

Question 26

process in which homologous chromosomes exchange portions of their chromatids during meiosis

Answer 26

Crossing-over