PENN STATE BIOLOGY 110 TEST 2 CURRENT
VERSION 2025-2026 EXAM QUESTIONS AND
ACCURATE DETAILED ANSWERS GRADED A+
In humans the presence of a widow's peak (W) is dominant to no
widow's (w) peak, and dimples (D) are dominant to no dimples
(d). A woman who is heterozygous for a widow's peak and
dimples marries a man who is also heterozygous for widow's
peak but has no dimples.What is the chance that this couple will
have a child that has no widow's peak but does have dimples?
a. 1/16
b. 3/16
c. 9/16
d. 1/8
-Answer-d. 1/8
In cattle, coat color may be red (genotype RR), white (rr), or
roan (mixed red and white hairs, which occurs in Rr
heterozygotes). Which of the following crosses would produce
all roan offspring?
a. white × white
b. white × roan
c. red × white
d. roan × roan
e. red × roan
-Answer-c. red × white
,Two true-breeding stocks of pea plants are crossed. One parent
has red, axial flowers and the other has white, terminal flowers;
all F1 individuals have red, axial flowers. The genes for flower
color and location assort independently.Among the F2 offspring,
what is the probability of plants with white axial flowers?
a. 1/4
b. 3/16
c. 9/16
d. 1/16
e. 1/8
-Answer-b. 3/16
Hemophilia is a recessive X-linked disorder. Annette has
hemophilia, but her brother does not. What is the genotype of
Annette's mother?
a. homozygous dominant
b. heterozygous
c. homozygous recessive
-Answer-b. heterozygous
An organism that has a pair of different alleles for a character is
said to be ______.
a. Homozygous dominant
b. Homozygous
c. Heterozygous
d. Heterozygous recessive
-Answer-c. Heterozygous
, Alternative versions of a gene are called ____.
a. Phenotypes
b. Hybrids
c. Genotypes
d. Alleles
-Answer-d. Alleles
Which of the following represents a testcross?
a. ww x W-
b. WW x WW
c. ww x ww
d. Ww x Ww
-Answer-a. ww x W-
Which of the following statements about the experiment
diagrammed in the figure is true? (pea plant diagram)
a. If you crossed all the round-seeded pea plants from the F2
generation with true-breeding wrinkle-seeded pea plants, you
would get more round-seeded pea plants in the next generation
than if you crossed all the round-seeded pea plants from the F1
generation with true-breeding wrinkle-seeded pea plants.
b. The reason you do not see wrinkle-seeded pea plants in the F1
generation is because the round-seeded pea plants used to create
the F1 generation were not true-breeding strains.
c. The gene for round-seeded pea plants is on a different
chromosome from the gene for wrinkle-seeded pea plants, which
is why you get 25% wrinkle-seeded pea plants in the F2
generation.
-Answer-a. If you crossed all the round-seeded pea plants from
the F2 generation with true-breeding wrinkle-seeded pea plants,
VERSION 2025-2026 EXAM QUESTIONS AND
ACCURATE DETAILED ANSWERS GRADED A+
In humans the presence of a widow's peak (W) is dominant to no
widow's (w) peak, and dimples (D) are dominant to no dimples
(d). A woman who is heterozygous for a widow's peak and
dimples marries a man who is also heterozygous for widow's
peak but has no dimples.What is the chance that this couple will
have a child that has no widow's peak but does have dimples?
a. 1/16
b. 3/16
c. 9/16
d. 1/8
-Answer-d. 1/8
In cattle, coat color may be red (genotype RR), white (rr), or
roan (mixed red and white hairs, which occurs in Rr
heterozygotes). Which of the following crosses would produce
all roan offspring?
a. white × white
b. white × roan
c. red × white
d. roan × roan
e. red × roan
-Answer-c. red × white
,Two true-breeding stocks of pea plants are crossed. One parent
has red, axial flowers and the other has white, terminal flowers;
all F1 individuals have red, axial flowers. The genes for flower
color and location assort independently.Among the F2 offspring,
what is the probability of plants with white axial flowers?
a. 1/4
b. 3/16
c. 9/16
d. 1/16
e. 1/8
-Answer-b. 3/16
Hemophilia is a recessive X-linked disorder. Annette has
hemophilia, but her brother does not. What is the genotype of
Annette's mother?
a. homozygous dominant
b. heterozygous
c. homozygous recessive
-Answer-b. heterozygous
An organism that has a pair of different alleles for a character is
said to be ______.
a. Homozygous dominant
b. Homozygous
c. Heterozygous
d. Heterozygous recessive
-Answer-c. Heterozygous
, Alternative versions of a gene are called ____.
a. Phenotypes
b. Hybrids
c. Genotypes
d. Alleles
-Answer-d. Alleles
Which of the following represents a testcross?
a. ww x W-
b. WW x WW
c. ww x ww
d. Ww x Ww
-Answer-a. ww x W-
Which of the following statements about the experiment
diagrammed in the figure is true? (pea plant diagram)
a. If you crossed all the round-seeded pea plants from the F2
generation with true-breeding wrinkle-seeded pea plants, you
would get more round-seeded pea plants in the next generation
than if you crossed all the round-seeded pea plants from the F1
generation with true-breeding wrinkle-seeded pea plants.
b. The reason you do not see wrinkle-seeded pea plants in the F1
generation is because the round-seeded pea plants used to create
the F1 generation were not true-breeding strains.
c. The gene for round-seeded pea plants is on a different
chromosome from the gene for wrinkle-seeded pea plants, which
is why you get 25% wrinkle-seeded pea plants in the F2
generation.
-Answer-a. If you crossed all the round-seeded pea plants from
the F2 generation with true-breeding wrinkle-seeded pea plants,
