BIOL 4003 EXAM 1 questions well
answered graded A+
True-breeding tall plants with purple flowers are crossed to true-breeding dwarf plants with
white flowers. The F1 plants were tall with purple flowers. The genes that affect these traits
independently assort. If the F1 plants were crossed to dwarf plants with white flowers, the
expected ratio of the F2 generation would be - correct answer ✔✔ 1 tall/white flowers : 1
tall/purple flowers : 1 dwarf/white flowers : 1 dwarf/ purple flowers
Which event during meiosis explains Mendel's law of segregation? - correct answer ✔✔
Separation of homologs during anaphase I of meiosis
Which of the following is a molecular explanation for the effects of a rare allele that is dominant
over the normal (wild-type) allele?
a. haploinsufficiency
b. gain-of-function mutation
c. dominant negative mutation
d. All of the other 3 choices are possible. - correct answer ✔✔ All of the other 3 choices are
possible.
Red/green colorblindness is an X-linked recessive trait. A mother with normal vision and a father
with red/green colorblindness have a daughter with red/green colorblindness. Assuming that an
offspring can be male or female, what is the probability that their next child will be a male with
red/green colorblindness? - correct answer ✔✔ 25%
A cross is made between two individuals that are AaBbCcDd. What is the probability that an
offspring will be AaBbCcDD? - correct answer ✔✔ 1/32
, A type B woman is the daughter of a type O father and type B mother. If she has children with a
type O man, what is the probability of having a child with type O blood? - correct answer ✔✔
50%
In chickens, brown feathers is dominant to white feathers. Let's suppose a heterozygote is
crossed to a chicken with white feathers. What is the probability of having three offspring, 2
offspring will have brown feathers and 1 with white? - correct answer ✔✔ 0.375
The length of the index finger is sex-influenced. The short allele is dominant in males, whereas
the long allele is dominant in females. If a heterozygous male and a female with short index
fingers have offspring together, what are the possible phenotypes of the offspring? - correct
answer ✔✔ males with short index fingers and females with short or long index fingers
Two different strains of plant exhibit a recessive phenotype of white flowers. When crossed,
they produce offspring with wild-type purple flowers. The outcome of this cross is called
______________ and it indicates that _________________________________. - correct answer
✔✔ complementation/the recessive alleles are in two different genes.
In (placental) mammals such as people, the process of X chromosome inactivation - correct
answer ✔✔ causes the formation of a Barr body.
In mice, a true-breeding female with a normal tail is crossed to a true-breeding male with a
short tail. All of the F1 offspring have normal tails. The F1 female offspring are then crossed to
true-breeding males with a short tail. All of the F2 offspring have normal tails. These are
observations are consistent with - correct answer ✔✔ both maternal effect and maternal
inheritance.
The Igf2 gene that is inherited from the mother is silenced due to imprinting. A mutation, which
we will call Igf2—, is a loss-of-function mutation. If an Igf2 Igf2— mother is crossed to an Igf2
Igf2 father, what is the predicted outcome? - correct answer ✔✔ All offspring would be normal.
answered graded A+
True-breeding tall plants with purple flowers are crossed to true-breeding dwarf plants with
white flowers. The F1 plants were tall with purple flowers. The genes that affect these traits
independently assort. If the F1 plants were crossed to dwarf plants with white flowers, the
expected ratio of the F2 generation would be - correct answer ✔✔ 1 tall/white flowers : 1
tall/purple flowers : 1 dwarf/white flowers : 1 dwarf/ purple flowers
Which event during meiosis explains Mendel's law of segregation? - correct answer ✔✔
Separation of homologs during anaphase I of meiosis
Which of the following is a molecular explanation for the effects of a rare allele that is dominant
over the normal (wild-type) allele?
a. haploinsufficiency
b. gain-of-function mutation
c. dominant negative mutation
d. All of the other 3 choices are possible. - correct answer ✔✔ All of the other 3 choices are
possible.
Red/green colorblindness is an X-linked recessive trait. A mother with normal vision and a father
with red/green colorblindness have a daughter with red/green colorblindness. Assuming that an
offspring can be male or female, what is the probability that their next child will be a male with
red/green colorblindness? - correct answer ✔✔ 25%
A cross is made between two individuals that are AaBbCcDd. What is the probability that an
offspring will be AaBbCcDD? - correct answer ✔✔ 1/32
, A type B woman is the daughter of a type O father and type B mother. If she has children with a
type O man, what is the probability of having a child with type O blood? - correct answer ✔✔
50%
In chickens, brown feathers is dominant to white feathers. Let's suppose a heterozygote is
crossed to a chicken with white feathers. What is the probability of having three offspring, 2
offspring will have brown feathers and 1 with white? - correct answer ✔✔ 0.375
The length of the index finger is sex-influenced. The short allele is dominant in males, whereas
the long allele is dominant in females. If a heterozygous male and a female with short index
fingers have offspring together, what are the possible phenotypes of the offspring? - correct
answer ✔✔ males with short index fingers and females with short or long index fingers
Two different strains of plant exhibit a recessive phenotype of white flowers. When crossed,
they produce offspring with wild-type purple flowers. The outcome of this cross is called
______________ and it indicates that _________________________________. - correct answer
✔✔ complementation/the recessive alleles are in two different genes.
In (placental) mammals such as people, the process of X chromosome inactivation - correct
answer ✔✔ causes the formation of a Barr body.
In mice, a true-breeding female with a normal tail is crossed to a true-breeding male with a
short tail. All of the F1 offspring have normal tails. The F1 female offspring are then crossed to
true-breeding males with a short tail. All of the F2 offspring have normal tails. These are
observations are consistent with - correct answer ✔✔ both maternal effect and maternal
inheritance.
The Igf2 gene that is inherited from the mother is silenced due to imprinting. A mutation, which
we will call Igf2—, is a loss-of-function mutation. If an Igf2 Igf2— mother is crossed to an Igf2
Igf2 father, what is the predicted outcome? - correct answer ✔✔ All offspring would be normal.
