NR293/ NR 293 Exam 2 solution guide 2022 Distinction level approved.

BIOL110 Exam 3 Mastering Bio Questions
(answered)
A gene that affects the expression of a second gene is an example of
__________________.
A. pleiotropy
B. codominance
C. epistasis
D. polygenic inheritance
E. incomplete dominance
C. epistasis
__________ is an example of a character that is controlled by more than one gene (a
quantitative character) and demonstrates a continuum of phenotypes.

A. Pleiotropy
B. Polygenic inheritance
C. Epistasis
D. Codominance
E. Incomplete dominance
B. Polygenic inheritance

The gene controlling ear color in an organism known as a gizmo has two alleles that
exhibit incomplete dominance: CR, which codes for red ears; and CY, which codes for
yellow ears. Individuals that are homozygous for the CR allele have red ears, whereas
the heterozygous genotype produces orange ears. Those that are homozygous for the
CY allele have yellow ears. If two individuals with orange ears are crossed, what ratio of
phenotypes should be expected in the offspring?
A. 9:3:1, red:yellow:orange ears
B. 3:1, red:yellow ears
C. 1:2:1, red:orange:yellow ears
D. 1:2:1, red:yellow:orange ears
E. 1:3, red:yellow ears
C. 1:2:1, red:orange:yellow ears

Mice with the genotypes BBCc and bbcc are crossed. The alleles for brown coat (b) and
no pigment (c) are recessive, and black coat (B) is dominant. What color of mice would
NOT be produced by this mating?
A. brown
B. white
C. black
A. brown

,An individual that is heterozygous for an allele and that exhibits a phenotype
intermediate between that of the two homozygous alternatives is an example of _____.
a.) polygenic inheritance
b.) pleiotropy
c.) codominance
d.) incomplete dominance
e.) epistasis
d.) incomplete dominance
What possible blood types could offspring have if their two parents have the blood types
A and AB, respectively?
A. AB only
B .A, B, AB, and O
C. A and O only
D. A and B only
E. A, B, and AB only
E. A, B, and AB only

In water snakes, body color is controlled by two alleles that display incomplete
dominance. Snakes with the BB genotype are brown, those with the Bb genotype are
gray, and individuals with the bb genotype are green. If a brown snake and a gray
snake are crossed, what ratio of phenotypes should be expected in the offspring?
A. 1:1, gray:green
B. 1:2:1, brown:gray:green
C. 1:1, brown:gray
D.1:1:1, brown:gray:green1:1, brown:green
C. 1:1, brown:gray

You are examining a trait which shows three distinct phenotypes, with the phenotype of
heterozygotes expressing both alleles seen in the homozygotes. This is an example of:
A. Codominance.
B. Complete dominance.
C. Incomplete dominance.
D. Pleiotrophy.
A. Codominance.

Pedigrees reveal that a trait shows a dominant pattern of inheritance if that trait
generally _______.
A. skipped generations
B. was lethal
C. did not skip generations
D. was only inherited by males
C. did not skip generations

________________________ is an example of a recessive inherited trait.
A. Huntington's disease
B.Cystic fibrosis

,C. Brachydactyly.
D. The AB blood type
B.Cystic fibrosis
If one parent who has Huntington's disease is heterozygous for the trait and the other
parent is not affected, what are the chances of their offspring inheriting the trait?
A. 50%
B. 100%
C. 0
D. 25%
A. 50%

If both parents are carriers of an recessive inherited trait, what are the chances that
their child will express that trait?
A. 50%
B. 25%
C. 0
D. 100%
...

The effects of ______________________ can be almost completely overcome by
regulating the diet of the individual from infancy. A. cystic fibrosis
B. sickle-cell disease
C. phenylketonuria (PKU)
D. Huntington's disease
C. phenylketonuria (PKU)

The following question refer to the pedigree chart in the figure below for a family, some
of whose members exhibit the dominant trait, W. Affected individuals are indicated by a
dark square or circle. What is the genotype of individual II-5?
ww


What is the likelihood that the progeny of IV-3 and IV-4 will have the
trait?
50%




What is the probability that individual III-1 is Ww?

1

, The figure below shows the pedigree for a family. Dark-shaded symbols represent
individuals with one of the two major types of colon cancer. Numbers under the symbols
are the individual's age at the time of diagnosis. Males are represented by squares,
females by circles.


From this pedigree, this trait seems to be inherited _____.

A. as a result of epistasis
B. as an autosomal dominant
C. as an autosomal recessive
D. from mothers
B. as an autosomal dominant

In rabbits, the homozygous genotype LCLC has normal legs, LCLc results in deformed
legs, and LcLc results in very short legs. The genotype FBFB produces black
fur, FBFb brown fur, and FbFb white fur. If a cross is made between brown rabbits with
deformed legs and white rabbits with deformed legs, what percentage of the offspring
would be expected to have deformed legs and white fur?
A. 25%
B. 100%
C. 50%
D. 33%
A. 25%

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant
allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines.
At the same time, a second gene, N, determines whether or not cacti have spines.
Homozygous recessive nn cacti have no spines at all. The relationship between
genes S and N is an example of which of the following inheritance patterns?
A. codominance
B. pleiotropy
C. incomplete dominance
D. epistasis
D. epistasis

Skin color in a certain species of fish is inherited via a single gene with four different
alleles. One fish of this type has alleles 1 and 3 (S1S3) and its mate has alleles 2 and 4
(S2S4). If each allele confers a unit of color darkness such that S1 has one unit, S2 has
two units, and so on, then what proportion of their offspring would be expected to have
five units of color?
A. 1/2
B. 1/8
C. 0
D. 1/4
A. 1/2