chapter 7

Question 1

two chromosomes: one from mother, one from father; same length and general appearance

Answer 1

homologous chromosomes

Question 2

chromosome pairs 1-22; genes not directly responsible for the sex of an organism

Answer 2

autosomes

Question 3

X and Y; female: XX, male: XY

Answer 3

sex chromosomes

Question 4

sex cells

Answer 4

gametes

Question 5

nuclear division that divides one diploid cell into four haploid cells

Answer 5

meiosis

Question 6

one half of a duplicated chromosome

Answer 6

chromatid

Question 7

differences in the genetic material of individuals in a population

Answer 7

genetic variation

Question 8

arrangement of any one homologous pair does not depend on the arrangement of any other homologous pair

Answer 8

independent assortment

Question 9

the exchange of chromosome segments between homologous chromosomes

Answer 9

crossing over

Question 10

distinguishing characteristics that are inherited

Answer 10

traits

Question 11

the mating of two organisms

Answer 11

genetic cross

Question 12

a piece of DNA that provides a set of instructions to a cell to make a certain protein

Answer 12

gene

Question 13

any of the alternative forms or versions of a gene that may occur at a specific locus

Answer 13

allele

Question 14

two of the same alleles at a specific locus

Answer 14

homozygous

Question 15

two different alleles at the same locus

Answer 15

heterozygous

Question 16

an organism’s actual genetic makeup

Answer 16

genotype

Question 17

the actual physical characteristics or traits of an individual

Answer 17

phenotype

Question 18

the allele that is expressed when two different alleles or two dominant alleles are present

Answer 18

dominant

Question 19

the allele that is only expressed when two recessive copies occur together

Answer 19

recessive

Question 20

heterozygous phenotype is somewhere between the two homozygous phenotypes

Answer 20

incomplete dominance

Question 21

both alleles of a gene are equally expressed and appear in the phenotype

Answer 21

codominance

Question 22

multiple genes contribute to the overall phenotype observed

Answer 22

polygenic trait

Question 23

genes that modify other genes

Answer 23

epistasis