Genetics Exam questions and
answers graded A+
Which of the following is NOT a correct statement about the process of meiosis?
A) Four haploid cells are produced from one diploid cell.
B) The DNA is replicated twice, and there are two rounds of division.
C) Synapsis and crossing-over occur during prophase I.
D) Meiosis I separates homologous chromosomes; meiosis II separates sister chromatids. -
ANS✅✅B
The pairing of homologous chromosomes during meiosis is known as __________.
A) nondisjunction
B) synapsis
C) linkage
D) segregation
E) crossing-over - ANS✅✅B
Which of the following conditions could ONLY result from non-disjunction in the father of the
affected
individual?
A) XYY
B) Klinefelter syndrome
C) Turner syndrome
D) Prader-Willi syndrome
E) Both A and B - ANS✅✅A
Feather color in a certain species of birds is controlled by the following pathway, in which the
enzymes
encoded by genes A and B are both required to produce a red pigment that gives the birds their
wild-type
feather color. If neither the red pigment nor its tan precursor is present, the feathers are white. The
null
, alleles (a and b) of both genes are recessive to the corresponding wild-type alleles (A and B). Which
of the
following statements is NOT consistent with the pathway as shown/described?
A) Genotype aa will be hypostatic to both alleles at the B locus.
B) A bird with genotype AAbb will have tan feathers.
C) Birds with genotypes aaBB, aaBb and aabb will all have the same phenotype.
D) A cross between two birds that are heterozygous at both loci will result in a ratio of 9 red : 3 tan :
4
white offspring. - ANS✅✅A
An X-linked recessive gene produces red-green color blindness in humans. A woman with normal
color
vision whose father was color-blind marries a color-blind man. What is the probability that their son
will be
color-blind?
A) 1/4 B) 1/2 C) 3/4 D) 1 E) 0 - ANS✅✅B
Wild-type porcupines have pointy quills. Scientists have identified several true-breeding strains of
porcupine that lack quills, giving them a "cuddly" phenotype. Crossing any cuddly mutant to a wild-
type
porcupine results in all wild-type offspring. The results of crosses between some of the true-
breeding
cuddly strains are as follows:
cud1 x cud2 = all cuddly offspring
cud2 x cud3 = all pointy offspring
cud1 x cud3 = ?
What is the result of a cross between cud1 and cud3?
A) all cuddly offspring
B) cannot be determined from the information given
C) all pointy offspring
D) half cuddly offspring and half pointy offspring - ANS✅✅C
answers graded A+
Which of the following is NOT a correct statement about the process of meiosis?
A) Four haploid cells are produced from one diploid cell.
B) The DNA is replicated twice, and there are two rounds of division.
C) Synapsis and crossing-over occur during prophase I.
D) Meiosis I separates homologous chromosomes; meiosis II separates sister chromatids. -
ANS✅✅B
The pairing of homologous chromosomes during meiosis is known as __________.
A) nondisjunction
B) synapsis
C) linkage
D) segregation
E) crossing-over - ANS✅✅B
Which of the following conditions could ONLY result from non-disjunction in the father of the
affected
individual?
A) XYY
B) Klinefelter syndrome
C) Turner syndrome
D) Prader-Willi syndrome
E) Both A and B - ANS✅✅A
Feather color in a certain species of birds is controlled by the following pathway, in which the
enzymes
encoded by genes A and B are both required to produce a red pigment that gives the birds their
wild-type
feather color. If neither the red pigment nor its tan precursor is present, the feathers are white. The
null
, alleles (a and b) of both genes are recessive to the corresponding wild-type alleles (A and B). Which
of the
following statements is NOT consistent with the pathway as shown/described?
A) Genotype aa will be hypostatic to both alleles at the B locus.
B) A bird with genotype AAbb will have tan feathers.
C) Birds with genotypes aaBB, aaBb and aabb will all have the same phenotype.
D) A cross between two birds that are heterozygous at both loci will result in a ratio of 9 red : 3 tan :
4
white offspring. - ANS✅✅A
An X-linked recessive gene produces red-green color blindness in humans. A woman with normal
color
vision whose father was color-blind marries a color-blind man. What is the probability that their son
will be
color-blind?
A) 1/4 B) 1/2 C) 3/4 D) 1 E) 0 - ANS✅✅B
Wild-type porcupines have pointy quills. Scientists have identified several true-breeding strains of
porcupine that lack quills, giving them a "cuddly" phenotype. Crossing any cuddly mutant to a wild-
type
porcupine results in all wild-type offspring. The results of crosses between some of the true-
breeding
cuddly strains are as follows:
cud1 x cud2 = all cuddly offspring
cud2 x cud3 = all pointy offspring
cud1 x cud3 = ?
What is the result of a cross between cud1 and cud3?
A) all cuddly offspring
B) cannot be determined from the information given
C) all pointy offspring
D) half cuddly offspring and half pointy offspring - ANS✅✅C
