Mr. Lastowski Biology I Honors GENETICS PRACTICE QUESTIONS

Mr. Lastowski
Biology I Honors
GENETICS PRACTICE QUESTIONS
1. Using the results of his experiments with pea plant
crosses, what did Gregor Mendel discover?
A) the laws of dominance, segregation, and
independent assortment
B) that pea plants develop mutations after
exposure to radiation
C) intermediate inheritance and gene linkage
D) that DNA is involved in the inheritance of
dominant traits
2. The puppies shown in the photograph below are all
from the same litter.
5. A child has brown hair and brown eyes. His father
has brown hair and blue eyes. His mother has red
hair and brown eyes. Which statement best
explains why the child has brown hair and brown
eyes?
A) a gene mutation occurred that resulted in
brown hair and brown eyes
B) gene expression must change in each
generation so evolution can occur
C) the child received genetic information from
each parent
D) cells from his mother's eyes were present in
the fertilized egg
6. A cross between two mice with long tails and
brown fur produced the four types of offspring
listed below:
long tailed with brown fur
long tailed with white fur
short tailed with brown fur short tailed with white fur
Which genetic mechanism best explains the results
of this cross?
A)
B)
C)
D)
The differences seen with this group of puppies are
most likely due to
A)
B)
C)
D)
overproduction and selective breeding
mutations and elimination of genes
evolution and asexual reproduction
sorting and recombination of genes
3. What most directly causes variation in the
offspring of sexually reproducing organisms?
A)
B)
C)
D)
sorting and recombining of genes
replication and cloning
the need to adapt and maintain homeostasis
overproduction of offspring and competition
4. Two pea plants, hybrid for a single trait, produce
60 pea plants. Approximately how many of the
pea plants are expected to exhibit the recessive
trait?
A) 15
B) 45
C) 30
D) 60
intermediate inheritance
gene linkage
independent assortment
crossing-over
7. In a certain type of plant, tall is dominant over
short, and green seed coat is dominant over yellow
seed coat. When two plants heterozygous for both
of these traits are crossed, the offspring produced
are tall, with green seed coats; tall, with yellow
seed coats; short, with green seed coats; and short,
with yellow seed coats. What do the results of this
cross illustrate?
A)
B)
C)
D)
vegetative propagation
mutagenic agents
intermediate inheritance
independent assortment
8. In humans, the gene for polydactyly (having extra
fingers or toes) is dominant over the gene for the
normal number of digits. If parents who are both
homozygous dominant for polydactyly have four
children, how many of these children would most
likely have extra fingers or toes?
A) 0
B) 2
C) 3
D) 4
9. What term would best be used to describe an
organism possessing two identical genes for a
trait?
A)
B)
C)
D)
heterozygous
hybrid homozygous incompletely dominant
10.A boy has brown hair and blue eyes, and his
brother has brown hair and brown eyes. The fact
that they have different combinations of traits is
best explained by the concept known as
A)
B)
C)
D)
multiple alleles
incomplete dominance
sex linkage
independent assortment
11.Which genetic concepts best explain the fact that
hybrid parents can produce offspring with
recessive phenotypes?
A)
B)
C)
D)
codominance and polyploidy
intermediate inheritance and segregation
segregation and recombination
polyploidy and recombination
14. For a given trait, the two genes of an allelic pair
are not alike. An individual possessing this gene
combination is said to be
A)
B)
C)
D)
homozygous for that trait
heterozygous for that trait
recessive for that trait
pure for that trait
15. In a certain species of mouse, gray fur (G) is
dominant over cream-colored fur (g). If a
homozygous gray mouse is crossed with a
cream-colored mouse, the genotype of the F1 generation will most likely be
A)
B)
C)
D)
100% Gg
50% GG and 50% gg
25% GG, 50% Gg, and 25% gg
75% Gg and 25% gg
16. Kernel color in corn is a trait determined by two
alleles. The dominant allele (P) produces a purple
color, and the recessive allele (p) produces a
yellow color. The diagram below shows an ear of
corn produced by crossing two corn plants. The
shaded kernels are purple, and the unshaded ones
are yellow.
12. When red-flowered snapdragons are crossed with
white-flowered snapdragons, all the F1 plants will
have pink flowers. If Mendel had used
snapdragons instead of pea plants, he would have
had difficulty in formulating his principle of
A) dominance
C) multiple alleles
B) sex-linked traits
D) mutation
13. The diagram below represents the inheritance of
stem height in garden peas.
The diagram best illustrates
A)
B)
C)
D)
intermediate inheritance
segregation and recombination
sex linkage and codominance
independent assortment
What can the yellow kernels best be described as?
A)
B)
C)
D)
homozygous dominant
heterozygous
hybrid
homozygous recessive
17. F represents the gene for brown coat color and f
represents the gene for white coat color. In the
cross FF x ff all the offspring have a brown coat.
Which genetic principle is illustrated by this
cross?
A) crossing-over
C) codominance
B) multiple alleles
D) dominance
18. Which genotype illustrates codominance of
alleles that control blood type in humans?
A) ii
B) I Ai
C) I BI B D) IAIB
19. In canaries, the gene for singing (S) is dominant
over the gene for non-singing (s). When hybrid
singing canaries are mated with non-singing
canaries, what percentage of the offspring is
likely to possess the singing trait?
A) 0%
C) 50%
B) 25%
D) 100%
20. In squirrels, the gene for gray fur (G) is dominant
over the gene for black fur (g). If 50% of a large
litter of squirrels are gray, the parental cross that
produced this litter was most likely
A) GG × Gg
C) Gg × gg
B) GO × GO
D) gg × gg
21. In a population of dogs, curly hair is dominant
over straight hair. If two parents are heterozygous
for this trait, what is the probability that any of
their offspring will have straight hair?
B) 25%
D) 100%
A) 0%
C) 75%
22. In dogs, wire hair (D) is dominant over smooth
hair (d). If two wire-haired dogs produce a
smooth-haired pup, the genotypes of the parent
dogs are most likely
A) DD andDd
C) DD and DD
B) Dd and Dd
D) Dd and dd
23. In screech owls, red feathers are dominant over
gray feathers. If two heterozygous red-feathered
owls are mated, what percentage of their
offspring would be expected to have red feathers?
A) 25%
C) 75%
B) 50
C) 100
100 % yellow
100% white
50% yellow, 50% white
25% yellow, 75% white
27. Only red tulips result from a cross between
homozygous red and homozygous white tulips.
This illustrates the principle of
A)
B)
C)
D)
independent assortment
dominance
segregation
incomplete dominance
28. In humans, the trait for polydactyly (having extra
fingers and toes) is dominant over the gene for
the normal number of digits. Which bar graph
best represents the expected percentages of
phenotypes among the offspring produced by a
heterozygous polydactyl individual and a
homozygous recessive individual?
A)
B)
C)
D)
D) 200
25. In pea plants, the trait for tall stems is dominant
over the trait for short stems. If two heterozygous
tall plants are crossed, what percentage of the
offspring would be expected to have the same phenotype as the parents?
A) 25%
C) 75%
A)
B)
C)
D)
B) 50%
D) 100%
24. The gene for tallness (T) is dominant over the
gene for shortness (t) in pea plants. A
homozygous dominant pea plant is crossed with a
heterozygous pea plant, and 200 seeds are
produced. Approximately how many of these
seeds can be expected to produce plants that are
homozygous dominant?
A) 0
26. In summer squash, white-colored fruit is
dominant over yellow-colored fruit. If
homozygous yellow-fruited plants are crossed
with heterozygous white-fruited plants, what is
the expected percentage of fruit color produced in
the offspring?
B) 50%
D) 100%
29. Two mice that are heterozygous for black coat
color are mated. Assuming coat color in mice is
controlled by a single pair of genes, which
genotypic ratio for coat color is expected in the
offspring?
A) 1:2:1 B) 9:7
C) 3:1
D) 1:3:1
30. The chart below indicates a method of
representing traits in pea plants.
34. In watermelon plants the allele for solid green
fruit (G) is dominant over the allele for striped
fruit (g). Pollen from a flower of a homozygous
green watermelon plant is used to pollinate a
flower from a heterozygous green watermelon
plant. What percent of the offspring of this cross
will bear striped watermelons?
A) 0%
C) 50%
Some offspring of a cross in pea plants were tall
and green. According to the chart, these plants
could be represented by
A) TTYY
C) ttYy
B) Ttyy
D) TtYy
31. In pea plants, the long-stem trait (L) is dominant
and the short-stem trait (l) is recessive. Two pea
plants were crossed, producing seeds that yielded
165 long-stem plants and 54 short-stem plants.
The genotypes of the parent plants were most
likely
A) Ll and LL
C) Ll and Ll
B) ll and ll
D) LL and ll
32. Base your answer to the following question on the
Punnett square below which shows the cross
between two squash plants.
Which genetic principle is best illustrated by the
phenotype of the offspring?
A)
B)
C)
D)
codominance
intermediate inheritance
independent assortment
dominance
33. In minks, the gene for brown fur (B) is dominant
over the gene for silver fur (b). Which set of
genotypes represents a cross that could produce
offspring with silver fur from parents that both
have brown fur?
A) Bb × Bb
C) BB × Bb
B) BB × bb
D) Bb × bb
B) 25%
D) 100%
35. In certain rats, black fur is dominant over white
fur. If two rats, both heterozygous for fur color,
are mated, their offspring would be expected to
have
A) four different genotypes and two different
colors
B) two different genotypes and three different
colors
C) three different genotypes and two different
colors
D) three different genotypes and three different
colors
36. B represents the dominant allele for a trait and b
represents the recessive allele. In which pair of
crosses must all of the offspring produced have
the same phenotype?
A)
B)
C)
D)
Bb × bb and Bb × Bb
Bb × bb and BB × Bb
BB × Bb and BB × bb
BB × BB and Bb × Bb
37. In humans, the ability to roll the tongue is
dominant over the inability to roll the tongue. If
two parents who are homozygous dominant for
this trait have 8 children, how many children
would be expected to be unable to roll their
tongues?
A) 0
B) 2
C) 8
D) 4
38. When a brown mink and a silver-blue mink were
crossed, all of the offspring produced were
brown. When these offspring were mated, they
produced 60 brown minks and 20 silver-blue
minks. Of the 60 brown minks, the number that
are heterozygous should be closest to
A) 10
B) 20
C) 40
D) 60
39. Changes in the genetic code of a human can be
transmitted to offspring if they occur in
A) cancer cells
C) cell membranes
B) gametes
D) antibodies
40. Base your answer to the following question on Two generations of offspring of four o'clock
plants are shown in the diagram below.
The phenotypic ratio of the F2 generation is
A) 3:1
B) 2:1:2
C) 2:1
41. In rats, black coat color is dominant over white
coat color. If some of the offspring of a cross
between a black rat and a white rat are white, the
black rat must have been
A) a polyploid
C) heterozygous
B) homozygous
D) a mutation
42. A cross between two tall garden pea plants
produced 314 tall plants and 98 short plants. The
genotypes of the tall parent plants were most
likely
A) TT and tt
C) Tt and Tt
B) TT and Tt
D) TT and TT
43. Which is a true statement about people with the
genotype I AI B for blood type?
A)
B)
C)
D)
They have two alleles that are codominant.
They exhibit a type O phenotype.
They are homozygous for blood type A.
They can have only type O children.
44. When two four-o'clock plants are crossed, 48 pink
four-o'clocks and 52 white four-o'clocks are
produced. The phenotypes of the parents are
A) pink and white
C) pink and pink
B) pink and red
D) red and white
45. When roan cattle are crossed, 25% of the
offspring produced will have white coats, 50%
will have roan coats, and 25% will have red
coats. What do these results illustrate?
A) polyploidy
C) codominance
B) crossing-over
D) sex linkage
D) 1:2:1
46. Crosses between white-coated cattle (C WCW) and
red-coated cattle (C R CR ) produce roan offspring
(C R CW). This type of inheritance pattern is
known as
A)
B)
C)
D)
multiple allele inheritance
crossing-over
sex linkage
codominance
47. If two roan cattle are crossed, what percent of the
offspring are expected to show the parental
phenotype for coat color?
A) 25%
C) 75%
B) 50%
D) 100%
48. A boy inherits genes for tallness, but his growth is
limited as a result of poor nutrition. This is an
example of
A)
B)
C)
D)
an inherited disorder
environmental influence on gene expression
expression of a hidden trait
a characteristic controlled by more than one
pair of genes
49. Identical twins separated at birth and raised by
different parents were found to have dramatically
different personalities. This finding provides
evidence for
A)
B)
C)
D)
mutation and genetic recombination
independent assortment
segregation of alleles
environmental influence on gene expression
50. Although identical twins inherit exact copies of
the same genes, the twins may look and act
differently from each other because
54. Base your answer to the following question on
Which statement best explains the change shown
in the diagram below?
A) a mutation took place in the gametes that
produced the twins
B) the expression of genes may be modified by
environmental factors
C) the expression of genes may be different in
males and females
D) a mutation took place in the zygote that
produced the twins
51. Scientific studies show that identical twins who
were separated at birth and raised in different
homes may vary in height, weight, and
intelligence. The most probable explanation for
these differences is that
A) original genes of each twin increased in
number as they developed
B) one twin received genes only from the
mother while the other twin received genes
only from the father
C) environments in which they were raised were
different enough to affect the expression of
their genes
D) environments in which they were raised
were different enough to change the genetic
makeup of both individuals
52. Identical twins were born with genes for a genetic
disorder that can be controlled by diet. Both twins
were placed on this diet, which excludes a certain
amino acid. However, one twin chose not to
follow the diet and developed the genetic
disorder. The other twin followed the diet and did
not develop the disorder. This difference between
the twins illustrates that
A) gene expression is not influenced by
biochemical factors
B) identical twins do not always have the same
genotype
C) gene expression is influenced by the
environment
D) the genetic disorder is inherited by identical
twins, only
53. Which cross could produce a child with blood
type A?
A) IAi ii
C) I Ai I BI B
B) I AI A I BI B
D) I BI B ii
A) Gene expression in an organism can be
modified by interactions with the
environment.
B) Certain rabbits produce mutations that affect
genes in specific areas of the body.
C) Sorting and recombination of genes can be
influenced by very cold temperatures.
D) Molecular arrangement in existing proteins
can be altered by environmental factors.
55. The warmer areas of the body of a Siamese cat
have light fur, and the cooler areas, such as the
ears and feet, are covered with dark fur. A
specific enzyme controls the production of the
pigment that causes the fur to become dark. One
inference that could be drawn about the enzyme
that controls dark pigment formation is that it is
A)
B)
C)
D)
more active at cooler temperatures
more active at warmer temperatures
denatured at cooler body temperatures
affected by an acidic pH
56. According to the gene-chromosome theory,
which statement is true?
A) Genes are present only on human
chromosomes.
B) Genes are arranged in a linear sequence on a
chromosome.
C) Alleles are located on nonhomologous
chromosomes.
D) Mutations occur mainly in sex cells
57. The genes for red hair and freckles are usually
inherited together because these genes are
A)
B)
C)
D)
homologous
sorted independently
linked
hybrid traits
58. A certain species of moth may have antennae that 63. Base your answer to the following question on are feathery or non-feathery. Those with feathery
the pedigree chart below and on your knowledge
antennae usually have red eyes, and those with
of biology. The chart shows the inheritance of
non-feathery antennae usually have white eyes. If
Tay-Sachs in a family.
antenna type and eye color are each controlled by
a single pair of genes, a valid conclusion that can
be drawn regarding the genes for antenna type
and eye color is that these genes are
A)
B)
C)
D)
on separate chromosomes
linked
polyploid
found at the same locus
59. When a person's teeth are being x rayed, other
body parts of this person are covered with a
protective lead blanket to prevent
A)
B)
C)
D)
loss of hair
increase in cell size
changes in DNA molecules
changes in glucose structure
60. Which situation would most directly affect future
generations naturally produced by a maple tree?
A) Ultraviolet radiation changes the DNA
sequence within some leaves of the tree.
B) Ultraviolet radiation changes the DNA
sequence within the gametes of some flowers
of the tree.
C) An increase in temperature reduces the
number of cell divisions in the roots.
D) Rapidly growing cells just under the bark are
exposed to radiation, causing changes in
genetic material.
61. In some individuals, G–A–G, the codon for
glutamic acid, is changed to G–U–G, the codon
for valine. This error causes red blood cells to
have a significant change in shape. This genetic
disorder is known as
A)
B)
C)
D)
albinism
hemophilia
Tay-Sachs
sickle-cell anemia
62. Which cross could produce a child with type O
blood?
A) I Ai × I BI B
C) I AI B × ii
B) I AI A × I Bi
D) IAi × IBi
What can be determined about Blanche's parents?
A) Neither parent has the allele for Tay-Sachs.
B) One parent has Tay-Sachs and the other is
normal.
C) One parent has the allele for Tay-Sachs and
the other does not.
D) Both parents have the allele for Tay-Sachs.
64. Which human genetic disorder results in the
condition illustrated by the drawing below of a
blood sample?
A)
B)
C)
D)
Down's syndrome
Tay-Sachs disease
sickle-cell anemia
hemophilia
65. A man with normal color vision married a woman
with normal color vision. The father of the
woman was colorblind. If this couple had a
daughter, what is the chance this child would be
colorblind?
A) 0%
C) 50%
B) 25%
D) 100%
66. The pedigree chart below represents the
inheritance of sickle-cell anemia through three
generations.
70. Base your answer to the following question on the
information and diagram below and on your
knowledge of biology.
In cats, gene E produces yellow fur and
gene B produces black fur. A cat that inherits
both of these genes has patches of yellow and
black fur and is known as a calico. The alleles
for black or yellow are located on the X
-chromosome. The cross XBY × XBXE is
illustrated in the square below.
Which symbols could be used to represent
individual 9 in generation III?
A)
B)
Yellow male offspring are represented by
C)
D)
A) 1
Base your answers to questions 67 through 69 on
the pedigree chart below which shows a history of
blood types.
B) 2
C) 3
D) 4
71. A mother pregnant with her fourth child
remarked, "This one just has to be a boy. It is
almost certain, since my other three children are
girls." Which statement best indicates the
accuracy of the mother's comment?
A) The mother is wrong because the chance of
having a boy is always 50%.
67. The blood types of the individuals represented in
the chart by 7 and 8 could be
A)
B)
C)
D)
A or B, only
AB, only
A, B, or AB, only
A, B, AB, or O
68. Which individuals represented by the chart must
be homozygous for blood type?
A) 1 and 2
C) 3 and 4
B) 2 and 3
D) 1 and 4
69. The genotype of the individual represented in the
chart by 5 is
A) I aI a
B) Iai
C) ii
D) I aI b
B) The mother is wrong because there is only a
25% chance that the child will be a boy.
C) The mother is right because the genes of the
father are dominant over those of the
mother.
D) The mother is right because a child usually
inherits both sex chromosomes from the
mother.
72. Which diagram illustrates fertilization that would
most likely lead to the development of a normal
human female?
A)
B)
C)
D)
Base your answers to questions 73 through 75 on the pedigree chart below. The pedigree chart represents the inheritance of color blindness
through three generations.
73. Which statement about the genotype of Linda and Donna regarding color blindness is correct?
A)
B)
C)
D)
Both carry one recessive allele.
Linda is a carrier, and Donna is homozygous dominant.
Both are homozygous recessive.
Linda is homozygous dominant, and Donna is a carrier.
74. Where is the allele for color blindness carried?
A)
B)
C)
D)
on the Y-chromosome, only
on the X-chromosome, only
on both the X- and Y-chromosomes
on neither the X- nor the Y-chromosome
75. Barbara is expecting another child. What is the probability that the new baby will be colorblind?
A) 0%
B) 25%
C) 50%
D) 100%
76. Base your answer to the following question on
The pedigree chart below shows the pattern of
inheritance for a sex-linked trait.
77. If a woman who is heterozygous for hemophilia
marries a normal man, which will be true of their
offspring?
A) All of their sons will be hemophiliac.
B) All of their daughters will be carriers of
hemophilia.
C) One-half of their daughters may be
hemophiliac.
D) One-half of their children of either sex may
receive the abnormal allele.
If this couple has another son, what is the
probability that he will exhibit this sex-linked
trait?
A) 0%
C) 50%
B) 25%
D) 100%
Answer Key
ClassicalGenetics
1.
A
37.
A
73.
A
2.
D
38.
C
74.
B
3.
A
39.
B
75.
C
4.
A
40.
D
76.
C
5.
C
41.
C
77.
D
6.
C
42.
C
7.
D
43.
A
8.
D
44.
A
9.
C
45.
C
10.
D
46.
D
11.
C
47.
B
12.
A
48.
B
13.
B
49.
D
14.
B
50.
B
15.
A
51.
C
16.
D
52.
C
17.
D
53.
A
18.
D
54.
A
19.
C
55.
A
20.
C
56.
B
21.
B
57.
C
22.
B
58.
B
23.
C
59.
C
24.
C
60.
B
25.
B
61.
D
26.
C
62.
D
27.
B
63.
D
28.
B
64.
C
29.
A
65.
A
30.
B
66.
B
31.
C
67.
D
32.
D
68.
D
33.
A
69.
B
34.
A
70.
D
35.
C
71.
A
36.
C
72.
A