BIO 100 Exam 4 UPDATED ACTUAL
Exam Questions and CORRECT Answers
Which of the following describes the human ABO blood group system? - CORRECT
ANSWER - Multiple alleles
Gene S controls the sharpness of cactus spines. SS and Ss cactuses have sharp spines while ss
cactuses have dull spines. At the same time, a second gene, N, determines whether cacti have
spines or not. nn cacti have no spines at all. What is the expected result of a cross between a true-
breeding sharp-spined cactus and a spinless cactus? - CORRECT ANSWER - All sharp-
pined cacti offspring.
A cross between homozygous purple-flowered and homozygous white-flowered pea plants
results in offspring all with purple-flowers. This demonstrates... - CORRECT ANSWER -
simple dominance.
A woman with blood type A positive has a daughter who is type O positive and a son who is type
B negative. Rh positive (R) is a trait that shows simple dominance over Rh negative (r). Which
of the following is a possible partial genotype for the son? - CORRECT ANSWER - IBi
Hydrangea plants of the same genotype are planted in a large garden. Some of the plants produce
blue flowers and other produce pink flowers. This can be best explained by which of the
following statements? - CORRECT ANSWER - Environmental factors such as soil pH
affect flower color.
A 1:2:1 phenotypic ratio in the F2 generation of a monohybrid cross is a sign of... - CORRECT
ANSWER - incomplete dominance.
Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the
other has white, terminal flowers. All the F1 have red, axial flowers. The genes for flower color
and position assort independently. If 1000 F2 offspring from this cross, approximately how many
of them would you expect to have red, terminal flowers? - CORRECT ANSWER - 190
, It was important that Mendel examined not just the F1 generation in his breeding experiments,
but the F2 generation as well, because... - CORRECT ANSWER - parental traits that were
not observed in the F1 reappeared in the F2.
The following pedigree describes the inheritance pattern for the dominant trait for wooly hair
(W). Affected individuals are indicated by solid symbols.
What is the genotype of individual B-5? - CORRECT ANSWER - ww
Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This
suggests... - CORRECT ANSWER - that the parents were both heterozygous.
Pea plants were particularly well suited for use by Mendel's breeding experiments for all of the
following reasons, except that... - CORRECT ANSWER - peas have an unusually long
generation time.
Which describes the ability of a single gene to have multiple phenotypic effects in the same
individual? - CORRECT ANSWER - Pleiotropy
The following pedigree describes the inheritance pattern for the dominant trait for wooly hair
(W). Affected individuals are indicated by solid symbols.
What is the likelihood that the progeny of C-4 and C-5 will have wooly hair? - CORRECT
ANSWER - 50%
Labrador retrievers have black, brown, or yellow coats. In a cross of a black female with a brown
male, results can be either all black puppies, 1/2 black and 1/2 brown puppies, or 3/4 black to 1/4
yellow puppies. These results indicate... - CORRECT ANSWER - that Epistasis is
involved.
Exam Questions and CORRECT Answers
Which of the following describes the human ABO blood group system? - CORRECT
ANSWER - Multiple alleles
Gene S controls the sharpness of cactus spines. SS and Ss cactuses have sharp spines while ss
cactuses have dull spines. At the same time, a second gene, N, determines whether cacti have
spines or not. nn cacti have no spines at all. What is the expected result of a cross between a true-
breeding sharp-spined cactus and a spinless cactus? - CORRECT ANSWER - All sharp-
pined cacti offspring.
A cross between homozygous purple-flowered and homozygous white-flowered pea plants
results in offspring all with purple-flowers. This demonstrates... - CORRECT ANSWER -
simple dominance.
A woman with blood type A positive has a daughter who is type O positive and a son who is type
B negative. Rh positive (R) is a trait that shows simple dominance over Rh negative (r). Which
of the following is a possible partial genotype for the son? - CORRECT ANSWER - IBi
Hydrangea plants of the same genotype are planted in a large garden. Some of the plants produce
blue flowers and other produce pink flowers. This can be best explained by which of the
following statements? - CORRECT ANSWER - Environmental factors such as soil pH
affect flower color.
A 1:2:1 phenotypic ratio in the F2 generation of a monohybrid cross is a sign of... - CORRECT
ANSWER - incomplete dominance.
Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the
other has white, terminal flowers. All the F1 have red, axial flowers. The genes for flower color
and position assort independently. If 1000 F2 offspring from this cross, approximately how many
of them would you expect to have red, terminal flowers? - CORRECT ANSWER - 190
, It was important that Mendel examined not just the F1 generation in his breeding experiments,
but the F2 generation as well, because... - CORRECT ANSWER - parental traits that were
not observed in the F1 reappeared in the F2.
The following pedigree describes the inheritance pattern for the dominant trait for wooly hair
(W). Affected individuals are indicated by solid symbols.
What is the genotype of individual B-5? - CORRECT ANSWER - ww
Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This
suggests... - CORRECT ANSWER - that the parents were both heterozygous.
Pea plants were particularly well suited for use by Mendel's breeding experiments for all of the
following reasons, except that... - CORRECT ANSWER - peas have an unusually long
generation time.
Which describes the ability of a single gene to have multiple phenotypic effects in the same
individual? - CORRECT ANSWER - Pleiotropy
The following pedigree describes the inheritance pattern for the dominant trait for wooly hair
(W). Affected individuals are indicated by solid symbols.
What is the likelihood that the progeny of C-4 and C-5 will have wooly hair? - CORRECT
ANSWER - 50%
Labrador retrievers have black, brown, or yellow coats. In a cross of a black female with a brown
male, results can be either all black puppies, 1/2 black and 1/2 brown puppies, or 3/4 black to 1/4
yellow puppies. These results indicate... - CORRECT ANSWER - that Epistasis is
involved.
