51) Any gene located on a sex chromosome
A) is called a recessive gene.
B) is called a sex-linked gene.
C) will exhibit pleiotropy.
D) will exhibit codominance.
52) Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female
fruit fly because
A) males are haploid.
B) the male’s phenotype results entirely from his single X-linked gene.
C) the male chromosome is more fragile than the female chromosome.
D) the male chromosome is more susceptible to mutations.
53) A colorblind woman marries a man who is not colorblind. All of their sons, but none of their
daughters, are colorblind. Which of the following statements correctly explains these results?
A) The gene for color vision is incompletely dominant to the gene for sex determination.
B) The gene for color vision is codominant with the gene for sex determination.
C) The gene for color vision is found on the X chromosome.
D) The gene for color vision is found on the Y chromosome.
54) Sex-linked conditions are more common in men than in women because
A) men acquire two copies of the defective gene during fertilization.
B) men need to inherit only one copy of the recessive allele for the condition to be fully
expressed.
C) the sex chromosomes are more active in men than in women.
D) the genes associated with the sex-linked conditions are linked to the Y chromosome, which
determines maleness.
15
55) According to scientists, about what percentage of men currently living in Central Asia may
be descended from the Mongolian ruler Genghis Khan?
A) 4%
B) 8%
C) 25%
D) 40%
56) Female inheritance patterns cannot be analyzed by simply studying the X chromosome
because
A) the X chromosome is too large to analyze effectively.
B) the X chromosome sometimes exchanges genetic information with the Y chromosome.
C) the X chromosome is obtained from both father and mother.
D) one X chromosome is deactivated in females.
57) Blood samples are taken from the heel of newborn babies to test for a mutation in the PKU
gene, which, if left untreated and in severe cases, can lead to mental retardation, reduced skin
pigmentation, and seizures. Which concept is being illustrated by this example?
A) incomplete dominance
B) polygenic inheritance
C) pleiotropy
D) codominance
58) If independent assortment did not occur, which of the following would be true?
A) Genes for two different traits would be inherited together as a pair.
B) Meiosis II would not be required to produce gametes, as meiosis I would be sufficient.
C) A dihybrid cross of heterozygous individuals would yield four different phenotypes.
D) Each sperm and egg would carry more than one allele for a specific gene.
59) In giraffes, long necks (N), long legs (L), dark spots (D), and the ability to digest meat (M)
are all dominant traits. What possible genotype could a long-necked, short-legged, light-spotted,
meat-digesting giraffe have?
A) NnllddMM
B) NNLLDdMm
C) NNllddmm
D) nnLLddMM
60) Below are two statements. Which (if any) applies to the law of segregation? Which (if any)
applies to the law of independent assortment?
I: Phenotypes for long tails and big eyes are inherited separately in lab mice.
II: A baby mouse inherits a maternal red eye allele and a paternal black eye allele.
A) A: segregation; B: independent assortment
B) A: independent assortment; B: segregation
C) A: segregation; B: segregation
D) A: independent assortment; B: independent assortment
61) In some cats, black coat color (B) is dominant over brown (B) and a striped fur pattern (S) is
dominant over a marbled fur pattern (s). You rescued a black striped cat from an animal shelter
but could not determine its exact genotype. To do so, you mated the cat with a brown marbled
cat. The mating produced 3 brown marbled, 2 brown striped, 2 black marbled, and 3 black
striped. Immediately, you concluded the genotype of your rescued cat was
A) BBSS.
B) BBSs.
C) BbSS.
D) BbSs.
62) You prepare a karyotype from a cell from an unknown organism. Upon analysis, you find 22
pairs of chromosomes that are each of equal length, and also a single pair that has one
chromosome longer than the other. What can you conclude from this information?
A) The organism that this cell came from is likely a female.
B) The organism that this cell came from is likely a male.
C) The organism that this cell came from has a genetic disease.
D) This cell is likely haploid.
63) Suppose that an elephant with the genotype EEFfggHh reproduces with an elephant with the
genotype eeFFGgHh. What is the probability that a baby elephant (called a calf) would have the
genotype EeFFGghh?
A) 1/16
B) 1/32
C) 1/64
D) 1/256
64) You are trying to determine the linkage map of a series of genes, X, Y, and Z, from
Caenorhabditis elegans, a nematode worm commonly used in scientific research. From doing
several crossover experiments, you know that the recombination frequency between X and Y is
11.5%, between Y and Z is 13%, and between X and Z is 25%. What is a possible sequence of
these genes?
A) X-Z-Y
B) Y-Z-X
C) Z-X-Y
D) X-Y-Z
65) Justin has type A blood and his wife Brittany has type B blood. Justin’s parents both have
type AB blood, and Brittany’s parents also both have type AB blood. What are the chances that
Justin and Brittany’s son Theodore has type A blood?
A) 100%
B) 75%
C) 25%
D) 0%
66) You are looking at an unknown cell under a microscope that has 22 chromosomes plus two
X chromosomes. Which of the following is the most likely identity of this cell?
A) a skin cell from a human female
B) an egg from a human female
C) an epithelial cell from a male chicken
D) an eye cell from a female grasshopper
9.2 Art Questions
1) Which plants in this figure must all be heterozygous?
A) purple-flowered plants in the P generation
B) white-flowered plants in the P generation
C) purple-flowered plants in the F1 generation
D) purple-flowered plants in the F2 generation
2) According to this figure, heterozygotes for this form of hypercholesterolemia suffer from the
disease because they
A) produce an abnormally shaped LDL receptor.
B) don’t produce any LDL receptors.
C) produce too many LDL receptors.
D) don’t produce enough LDL receptors.
9.3 Scenario Questions
After reading the paragraph below, answer the questions that follow.
A man and his wife are having trouble having a baby. Using modern technologies, the woman’s
eggs are removed, fertilized with her husband’s sperm, and implanted into her uterus. The
procedure is successful, and the woman gives birth to a healthy baby boy. After a while, though,
they discover that their son is colorblind and has blood type O. The woman claims that the child
can’t be theirs since she has blood type A and her husband has type B. Also, neither parent is
colorblind, although one grandparent (the woman’s father) is also colorblind.
1) As a genetic counselor, you would explain to the parents that
A) the eggs must have been accidentally switched, since the baby’s blood type has to match one
of his parents.
B) each parent could have contributed one recessive allele, resulting in type O blood.
C) the eggs must have been accidentally switched, since a type A parent and a type B parent can
have any type children except O.
D) it is possible for the baby to have type O blood, since type O is inherited through a dominant
allele.
2) In regard to the baby’s colorblindness, a sex-linked recessive trait, you explain that
A) colorblindness often appears randomly, even if neither parent is colorblind.
B) the baby’s father must have a recessive allele for colorblindness.
C) since colorblindness is sex-linked, a son can inherit colorblindness if his mother has the
recessive colorblindness allele.
D) the eggs must have been accidentally switched, since males inherit sex-linked traits only from
their fathers.
After reading the paragraphs below, answer the questions that follow.
During a summer study abroad program, you travelled to Austria to study genetics at the
University of Vienna. While you were there, a momentous discovery was made: some of Gregor
Mendel’s original lab books and notes were found to be buried outside of the abbey where he
lived. It just so happened that the professor you were working with obtained copies of these
notes and enlisted your help to decipher them.
You hired a translator to translate Mendel’s notes from Czech to English, and using your
knowledge of modern genetics (which Mendel did not have!) you were able to construct a partial
Punnett square (shown below). Because the notebook was damaged from being buried for so
long, this is the only information that you have regarding a cross that Mendel must have
performed. Your professor has tasked you with figuring out more about this experiment.
3) In pea plants, round peas are dominant (R) and shriveled peas are recessive (r) and yellow
peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are
recessive (y). Using this information and the partial Punnett square above, what were the
phenotypes of the parental plants that were used in this cross by Mendel?
A) Rryy and RrYy
B) Rryy and rrYy
C) RRyy and rryy
D) RrYy and RrYy
4) In pea plants, round peas are dominant (R) and shriveled peas are recessive (r), and yellow
peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are
recessive (y). Using this information and the partial Punnett square above, what genotype should
be listed in the square labeled A?
A) RRYY
B) RrYy
C) rrYy
D) RRyy
5) In pea plants, round peas are dominant (R) and shriveled peas are recessive (r,) and yellow
peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are
recessive (y). Using this information and the partial Punnett square above, what phenotype
should be in the square labeled B?
A) round and yellow
B) shriveled and yellow
C) shriveled and green
D) round and green
6) In pea plants, round peas are dominant (R) and shriveled peas are recessive (r), and yellow
peas (shown as light gray in Punnett square) are dominant (Y) and green peas (dark gray) are
recessive (y). Using this information and the partial Punnett square above, what is the phenotypic
ratio of the offspring pea plants in this Punnett square?
A) 12:1:1:4
B) 9:3:3:1
C) 3:3:1:1
D) 1:1:1:1
After reading the paragraphs below, answer the questions that follow.
Cats normally have a total of 18 toes, 5 on each front paw and 4 on each back paw. But some
cats express the dominant phenotype for polydactyly, which results in the development of extra
toes on one or more paws. Jake, a Canadian tabby cat, has 28 toes and is recognized by the
Guinness Book of World Records as the cat with the most toes.
Suppose that Jake mates with a female cat, Lucy, who has 18 total toes. Over several years, they
have multiple litters and a total of 16 kittens (10 males and 6 females). The total number of toes
on each kitten ranges from 21 to 25.
7) If we use the letter P to represent the polydactyly gene, what is Jake‘s genotype?
A) PP
B) Pp
C) pp
D) You cannot determine Jake’s genotype from this information.
8) One of Jake and Lucy’s kittens mates with another cat that has 18 total toes. What is the
probability that one of their offspring would have 18 total toes?
A) 100%
B) 75%
C) 50%
D) 0%
9) Along with having a variable number of toes, some kittens from Jake and Lucy’s litter had a
white spot on their nose. In fact, out of the 16 kittens, all 10 males had the white spot, but none
of the 6 females had the white spot. Jake has a white spot on his nose, but Lucy does not. What
can you conclude from this information?
A) A sex-linked gene that controls the expression of the white spot is found on the Y
chromosome.
B) A sex-linked gene that controls the expression of the white spot is found on the X
chromosome.
C) The genes for the white spot and for polydactyly are linked.
D) The genes for the white spot and for polydactyly are not linked.