31) In order to track the inheritance of two characters, you would need to do a:

A) monohybrid cross.

B) dihybrid cross.

C) trihybrid cross.

D) true-breeding cross.

32) In humans, freckles are dominant to no freckles, and unattached earlobes are dominant to attached earlobes. Two individuals who both have freckles and unattached earlobes have a child with no freckles and attached earlobes. What are the genotypes of the parents? (F = freckles; E = unattached earlobes)

A) FFEE x ffee

B) Ffee x FFEE

C) FfEe x FfEe

D) FFEE x FFEe

E) ffee x ffee

33) In Mendel’s pea plants, yellow seeds are dominant to green seeds. Purple flowers are dominant to white flowers. Use Y and y for the seed color alleles and P and p for the flower color alleles. Flower color and seed color assort independently. A plant of unknown genotype with yellow seeds and purple flowers is crossed to a plant with green seeds and white flowers. The offspring all have yellow seeds, but some have purple flowers, and some have white flowers. What is the genotype of the yellow-seeded, purple-flowered plant?

A) YyPp

B) YYPp

C) YyPP

D) YYPP

E) Yypp

34) In Mendel’s pea plants, yellow seeds are dominant to green seeds. Purple flowers are dominant to white flowers. Use Y and y for the seed color alleles and P and p for the flower color alleles. Flower color and seed color assort independently. A true-breeding plant with green seeds and white flowers is crossed to a plant that is heterozygous for the genes for both phenotypes. What is the probability that the cross will yield a plant with green seeds and white flowers?

A) 3/16

B) 3/32

C) 1/32

D) 1/16

E) 1/4

35) In Mendel’s pea plants, yellow seeds are dominant to green seeds. Purple flowers are dominant to white flowers. Use Y and y for the seed color alleles and P and p for the flower color alleles. Flower color and seed color assort independently. If a plant that is heterozygous for both flower color and seed color genes is self-fertilized, what proportion of the offspring will have one of the dominant phenotypes, either the seed color or flower color, but not both?

A) 6/64

B) 6/32

C) 6/16

D) 9/32

E) 9/16

36) When Mendel crossed heterozygotes for flower color and seed color, what proportion of the offspring had both dominant phenotypes?

A) 3/4

B) 3/16

C) 1/3

D) 1/16

E) 9/16

37) In Mendel’s pea plants, yellow seeds are dominant to green seeds. Purple flowers are dominant to white flowers. Use Y and y for the seed color alleles and P and p for the flower color alleles. Flower color and seed color assort independently. What is the relationship between the Y and P?

A) They are two different genes on two different chromosomes.

B) They are two different genes on the same chromosome.

C) They are two different chromosomes in the pea plant.

D) They are the pleiotropic effects of a single gene.

E) They are incompletely dominant alleles of the same gene.

38) Mendel’s work was presented in ________ but not recognized and rediscovered until ________.

A) 1825; 1950

B) 1865; 1900

C) 1850; 1900

D) 1800; 1900

E) 1890; 1920

39) Crossing two pink snapdragons yields some seeds that produce red-flowering plants, some seeds that produce white-flowering plants and some seeds that produce pink-flowering plants. If this trait operates by incomplete dominance and the allele R represents red flowers and the allele r represents white flowers, what genotype would a plant with pink flowers have for this trait?

A) RR

B) Rr

C) rr

D) RrRr

40) What is the basis for incomplete dominance?

A) Both alleles of a gene produce weakly functioning proteins.

B) One allele produces some functioning protein; the other allele is nonfunctional.

C) Crossing over has switched alleles for a gene on homologous chromosomes.

D) One gene has many effects.

E) An individual has more than two alleles for a gene.