Download Practice Exam 3, Biology 211, Sections 1 and 4, Fall, 2007

Practice Exam 3
Biology 211
1. Which of the following statements about the relationship between DNA molecules and chromatids is
correct?
a. Each chromatid contains a single linear DNA molecule.
b. Each chromatid contains a large number of circular DNA molecules.
c. The number of DNA molecules per chromatid varies between one and two depending on the time in the
cell cycle.
d. The number of DNA molecules per chromatid is described by the term ploidy. Thus, diploid cells
contain two, tetraploid four, etc.
e. Each gene is a DNA molecule, and chromosomes contain many genes, therefore each chromatid contains
a large number of linear DNA molecules.
2. Which of the following terms refers to structures with similar, but not identical, DNA molecules?
a. diploids
b. homologous chromosomes
c. sister chromatids
d. homologs
e. choices b and d are both correct
3. How many chromosomes and how many chromatids are present in a haploid cell during metaphase if a
diploid cell from the organism has 48 chromosomes during G1?
a) 24 and 24;
b) 24 and 48;
c) 48 and 48;
d) 48 and 96;
e) 96 and 96.
4. Which of the following statements about meiosis is correct?
a. One purpose of meiosis is to assure that sexual reproduction does not double the amount of DNA per cell
each generation.
b. One purpose of meiosis is to assure that daughter cells are essentially identical.
c. One purpose of meiosis is to provide a large amount of variation within a population.
d. Choices a and c are both correct.
e. Choices a, b, and c are all correct.
5. What is a major difference between Prophase of Meiosis I and Prophase of Meiosis II?
a. DNA synthesis occurs in Prophase I, but not in Prophase II.
b. Recombination occurs in Prophase I, but not in Prophase II.
c. The spindle forms in Prophase II, but not Prophase I.
d. Chromosomes line up in the center of the cell in Prophase I. Chromosomes do not line up in Prophase II.
e. Choices b and c are both correct.
6. A diploid brain cell from a female mouse has 22 chromosomes in Metaphase. How many chromosomes and
how many chromatids are present in prophase of meiosis II in this mouse?
a. 11 chromosomes and 11 chromatids
b. 11 chromosomes and 22 chromatids
c. 22 chromosomes and 11 chromatids
d. 22 chromosomes and 22 chromatids
e. 22 chromosomes and 44 chromatids
1
7. A Drosophila melanogaster sperm cell has four chromosomes. How many DNA molecules, how many
chromatids, and how many chromosomes are present in a Drosophila cell nucleus during metaphase
of Meiosis I?
a. 4 DNA Molecules, 4 chromatids, and 4 chromosomes
b. 8 DNA Molecules, 8 chromatids, and 4 chromosomes
c. 8 DNA Molecules, 8 chromatids, and 8 chromosomes
d. 16 DNA Molecules, 8 chromatids, and 8 chromosomes
e. 16 DNA Molecules, 16 chromatids, and 8 chromosomes
8. A tetraploid marigold cell has 48 chromosomes in its nucleus during the G1 portion of the mitotic cell cycle.
How many chromosomes are present in a cell from the same plant which is in the metaphase of meiosis II?
a. 96
b. 48
c. 24
d. 12
e. 6
9. The transmission of traits from one generation to another is called:
a.) genetic recombination.
b.) meiosis.
c.) gene transmission.
d.) inheritance.
10. Chromosomes in a pair that have the same length, staining pattern, and centromere
position are known as_________________.
a.) homolougues.
b.) sister chromatids
c.) somatic chromosomes.
d.) none of the above.
11. Gametes are produced by ____________ which takes place in the _____________ part of
the life cycle.
a.) mitosis, haploid.
b.) mitosis, diploid.
c.) meiosis, diploid.
d.) meiosis, haploid.
12. Which of the following is not true about alleles?
a.) Alleles are another name for sister chromatids.
b.) Alleles are alternate versions of genes.
c.) Alleles account for the variation in inherited characters.
d.) All of the above are true.
13. What are the resulting probabilities of a cross between QQ and Qq?
a.) 25% QQ: 50% Qq: 25% qq
b.) 50% QQ: 25 Qq: 25% qq
c.) 50% QQ: 50% Qq
d.) 75% QQ: 25% Qq
14. Cyctic Fibrosis is an example of __________________.?
a.) plieotrophy
b.) multiple alleles
c.) epistasis
d.) incomplete dominance
15. Trisomy 21 is an example of_________________.
a.) Polyploidy
b.) Aneuploidy
c.) monosomy
d.) none of the above.
16. Darwin coined the term________________.
a.) evolution
b.) gradualism
2
c.) natural selection
d.) uniformitarianism.
17. What is the differential success in reproduction that results from the interaction between
individuals that vary in heritable traits and their environments?
a.) survival of the fittest.
b.) natural selection
c.) evolution
d.) inheritance
18. What is the smallest unit that can evolve?
a.) family
b.) an individual
c.) population
d.) species
19. A localized group of individuals capable of interbreeding and producing fertile offspring
is a__________________.
a.) species
b.) family
c.) pack
d.) population.
20. New genes and alleles originate only by
a.) mutations
b.) genetic drift
c.) natural selection
d.) gene flow
21. Which of the following is not a condition for Hardy-Weinberg Equilbirum?
a.) Extremely large population size
b.) No gene flow
c.) Mutations must occur
d.) No Natural Selection can occur.
22. If a typical somatic cell has 24 chromosomes, how many chromosomes are expected in a
normal gamete?
a.
48
b. 24
c.
12
d. 6
e.
The information given is insufficient to answer the question
23. In New Zealand, a new species of animal is found. There are three feather colors that
occur frequently in the population: black, white, and grey with black seeming to be
dominant. Which is a reasonable explanation, assuming that feather color is controlled
by a single gene?
a.
Pleiotropy
b.
Incomplete dominance
c.
Polygenic Inheritance
d.
The grey feather color is the result of a mutation
24. Green leaves are dominant to yellow leaves and blue berries are dominant to purple
berries. You find a green leafed, blue berried plant. What must you do to determine this
plant’s genotype?
3
a.
b.
c.
d.
Cross it to a pure breeding green leafed, blue berry plant
Cross it to a pure breeding green leafed, purple berry plant
Cross it to a pure breeding yellow leafed, blue berry plant
Cross it to a pure breeding yellow leafed, purple berry plant
25. A man with type B blood fathers children with a woman who also has type B blood.
What is/are the possible blood type/s of their offspring?
a.
B only
b.
A or B
c.
A, B, or O
d.
O only
e.
B or O
26. Homologous chromosomes
a. Line up on the metaphase plate of Metaphase I
b. Carry the same genetic loci
c.
Segregate during meiosis
d. All of the above
27. When does crossing over occur?
a. Mitosis
b. Metaphase I
c. Metaphase II
d. Prophase I
e. S phase
28. Mendel’s Law of Independent Assortment is fulfilled by movement of the
chromosomes in which stage of cell division?
a.
Metaphase of mitosis
b. Anaphase of meiosis I
c.
Anaphase of meiosis II
d. Metaphase of meiosis I
e.
Cytokinesis in animal cells
29. Crossing over occurs between:
a. Sister chromatids of a homologous pair
b. Non-sister chromatids of a homologous pair
c.
Any two chromosomes that happen to line up next to each other at metaphase
d. The sex chromosomes only
e.
More than one of the above is true about crossing over
30.
Which of the following observations did not lead Darwin to propose the Theory
of Evolution?
a.
The existence of variation within natural populations
b.
Relatively stable size of natural populations
c.
Presence of different fossil species in different strata
4
d.
e.
Stable (constant) environmental conditions through time
All of the above lead Darwin to propose the Theory of Evolution
31.
a.
b.
c.
d.
e.
What is are homologous characters?
Traits derived from adaptation to similar environments
Traits derived from a shared common ancestor
Adaptations that perform the same function in different species
Adaptations that perform different functions in different species
None of the above
32.
a.
b.
c.
d.
e.
f.
Which of the following provide evidence that supports the Theory of Evolution?
Presence of vestigial organs
“Transition” fossil species
Homologous genes
Similar features in Embryonic development among chordates
Some but not all of the above
All of the above
33.
a.
b.
True or False. An individual can evolve.
True
False
34.
True or False. Natural selection influences the rate at which favorable mutations
occur.
a.
True
b.
False
35.
a.
b.
True or False. The mechanism of evolution is natural selection.
True
False
36.
Which of the following are examples of evolution that can be observed in human
life times?
a.
Insect species becoming pesticide-resistant
b.
Infectious disease gaining antibiotic resistance
c.
The transition from wild wolves to domestic dogs
d.
A & B only
e.
All of the above
37.
a.
b.
c.
d.
e.
Which of the following is a false statement about linked genes?
Are located on the same chromosome
Do not separate independently in gamete formation
Separate independently in gamete formation
Tend to be inherited together
C&D
5
38.
a.
b.
c.
d.
Which statement accurately describes recombination frequency?
The more frequently recombination happens between two genes, the closer
together the loci are
The more frequently recombination happens between two genes, the farther
apart the loci are
The frequency of recombination has nothing to do with the distance between two
genes on a chromosome
None of the above
39.
Mendel proposed the Law of Segregation without any knowledge of the existence
of chromosomes. Which of the following supports Mendel’s Law?
a.
Independent assortment in Meiosis
b.
Formation of identical cells in Mitosis
c.
Some genes are linked
d.
All of the above
e.
None of the above
40.
A woman with AB blood has children with a man who has type O blood. What
are the possible blood types of their children?
a.
Type A only
b.
Type B only
c.
Type A and Type B
d.
Type A, Type B, Type AB
e.
Type A, Type B, Type AB, and Type O
41.
In a certain species of frog, yellow eyes are dominant to grey eyes and brown
spots are
dominant to purple spots. If a two frogs that are each heterozygous for
both traits mate, what proportion of the offspring will have yellow-eyes and purple-spots?
a.
1/2
b.
¼
c.
5/16
d.
3/16
e.
none of the above
42.
Upon arriving on Pluto, you discover a new race of aliens. You observe that
Plutonions range from having no orange spots at all to being almost completely covered
in orange spots, with a whole spectrum of orange-spottedness in between. Assuming the
Plutonions are a sexually reproducing diploid species, which of the following is a
reasonable guess concerning the inheritance pattern of the orange spot trait?
f.
Incomplete Dominance
g.
Pleiotropy
h.
Polygenetic Inheritance
i.
Multiple alleles
j.
All of the above are reasonable guesses
6
43. A human cell containing 22 autosomes and a Y chromosome is:
a. a somatic cell of a male
b. a zygote
c. a somatic cell of a female d. a sperm
44.Homologous chromosomes move toward opposite poles of a dividing cell during:
a. mitosis
b. meiosis I c. meiosis II d. fertilization
e. binary fission
45. Crossing over usually contributes to genetic variation by exchanging chromosomal
segments between:
a. sister chromatids of a chromosome
b. chromatids of nonhomologous chromosomes
c. nonsister chromatids of homologues
d nonhomologous loci of the genome
46. Meiosis II is similar to mitosis in that:
a. homologous chromosomes synaps
b. DNA replicates before the division
c. the daughter cells are diploid d. sister chromatids separate during anaphase
47. A heterozygous individual is crossed with a homozygous dominant individual. The
probablility of getting a heterozygote is:
a. 0
b. .25
c. .50
d. .75
48. In mice, grey coat color is( mix of black and white hairs) occurs in the heterozygous
individuals (Gg). When two grey mice are crossed, the phenotypes of the progeny are
1black:2grey:1white. Which of the following of the crosses would produce the highest
percentage of grey mice?
a. Grey X Grey
b. Grey X Black
c. White X Black
d. White X Grey
49. There is good evidence for linkage when:
a. multiple alleles are found
b. a gene is recessive to a dominant allele
c. two genes work together to control a specific characteristic
d. genes do not segregate independently during meiosis
e. blending inheritance occurs
50. A recessive allele in the X chromosome is responsible for hemophilia in humans. A
woman with normal blood clotting whose mother was a hemophiliac marries a man who
has normal blood clotting. Which of the following is possible:
a. They may have daughters with hemophilia
b. They may have hemophilic sons
c. none of their children could have hemophilia e. all of the above d. none of the above
51. The ABO blood types in humans is an example of:
a. multiple alleles
b. epistasis
c.pleiotrophy
d. polygenic inheritance
d. codominance
e. all of the above
f. more than one of above
52. ___________ occurs when a gene at one locus alters the expression of a gene at a
second locus. ____________ is an additive effect of two or more genes on a single
phenotypic character.
a. pleiotrophy; epistasis
b. epistasis; polygenic inheritance
7
c. polygenic inheritance: epistasis
d. epistasis; pleiotrophy
53. Crossing over is important because:
a. it causes segregation
b. it aligns the chromosomes at metaphase II of meiosis
c. it creates new combinations of alleles on homologous chromosomes
d. it causes mutations
54. A geneticist mixed together many different kinds of fruit flies- some with long wings,
some with short wings, some with long legs, and some with short legs. He allowed the
flies to feed, mate randomly, and reproduce by the thousands. After many generations,
most of the flies in the population had medium length wings and medium length legs, and
most of the extreme types disappeared. This illustrates:
a. stabilizing selection
b. diversifying selection
c. fitness
d. genetic drift
55. In a population that is in Hardy-Weinberg equilibrium, the frequency of a recessive
allele in the gene pool is 0.7. The frequency of organisms in this population with the
homozygous dominant genotype will be:
a. 49%
b.14%
c. 21%
d. %9
e. 7%
56. A bottleneck event is a non-adaptive feature that:
a. shows a fluctuation in allele frequencies
b. results in a large population crash
c. results in crossing over
d. all of the above
e. none of the above
57. Down Syndrome is caused by _____ of chromosome 21.
a. deletion
b. translocation
c. nondisjunction
d. insertion
58. Meiosis results in ______.
a. two identical cells
b. two non-identical cells
c. four identical cells
d.four non-identical cells
59. AaBb is ______ at two loci.
a. epistatic
b. homozygous
c. linked
d. heterozygous
60. Mating red flowers with yellow flowers makes all orange flowers.
This is an example of ______.
a. codominance
8
b. incomplete dominance
c. complete dominance
d. dominant and recessive
61. The recombination frequencies are as follows: A to B is 14%, B to C is 5%, and C to
A is 9%. What is the order of genes on the chromosome?
a. ACB
b. ABA
c. CAB
d. ABC
62. A human gamete contains _____ chromosomes.
a. 13
b. 46
c. 23
d. 92
63. Plants are commonly _______, having multiple sets of chromosomes.
a. haploid
b. monoploid
c. anueploid
d. polyploid
64. In fruit flies, red eyes (W) are dominant over white eyes (w). You cross an unknown
genotype with a fly that is homozygous recessive and end up with all red-eyed flies. What
was the genotype of the unknown?
a. ww
b. Ww
c. WW
d. not enough information
65. According to Mendel’s law of segregation,
a. There is a 50% probability that a gamete will get a dominant allele
b. Gene pairs segregate independently of other genes in gamete formation
c. Allele pairs separate in gamete formation
d. The laws of probability determine gamete formation
e. There is a 3:1 ratio in the F2 generation
66. A 1:1 phenotypic ration in a testcross indicates that
a. The alleles are dominant
b. One parent must have been homozygous recessive
c. The dominant phenotype parent was a heterozygote
d. The alleles segregate independently
e. The alleles are co-dominant
9
67. If both parents are carriers of a lethal recessive gene, the probability that their
child will inherit and express the disorder is
a. 1/8
b. ¼
c. ½
d. ¾
e. 0
68. In a dihybrid cross of heterozygote, what proportion of the offspring will be
phenotypically dominant for both traits?
a. 1/16
b. 3/16
c. ¼
d. 9/16
e. ¾
69. You think that two alleles for coat color in mice show incomplete dominance.
What is the best and simplest cross to perform in order to support your
hypothesis?
a. A testcross of a homozygous recessive mouse with a mouse of unknown
genotype
b. A cross of F1 mice to look for a 1:2:1 ration the offspring
c. A cross between two true-breeding mice of different colors to look for an
intermediate phenotype in the F1
d. A cross of F1 mice to look for a 9:3:4 ratio in the offspring
70. Which of the following is not a source of genetic variation in sexually
reproducing organisms?
a. Crossing over
b. Replication of DNA during S phase before Meiosis I
c. Independent assortment of chromosomes
d. Random fertilization of games
e. Mutations
71. Meiosis II is similar to mitosis because
a. Sister chromatids separate
b. Homologous chromosomes separate
c. DNA replication precedes the division
d. They both take the same amount of time
e. Haploid cells are produced
72. Homologous chromosomes
a. Have identical genes
b. Have genes for the same traits at the same loci
c. Are found in gametes
d. Separate in Meiosis II
e. Have all of the above characteristics
10
73. If a populations has the following genotype frequencies, AA = .42; Aa = .46; aa =
.12; what are the allele frequencies?
a. A = .42; a = .12
b. A = .6; a = .4
c. A = .65; a = .35
d. A = .76; a = .24
e. A = .88; a = .12
74. In a population with two alleles, B and b, the allele frequency of b is .4. What
would the frequency of heterozygotes be if the population was in HardyWeinberg equilibrium?
a. .16
b. .24
c. .48
d. .6
e. You cannot tell from this information
75. Darwinian fitness is a measure of
a. Survival
b. Number of matings
c. Adaptation to the environment
d. Successful competition for resources
e. Number of viable offspring
76. In a study of a population of field mice, you find that 48% of mice have a coat
color that indicates that they are heterozygous for long tails. What would be the
frequency of the dominant allele in the population?
a. .24
b. .48
c. .50
d. .60
e. You cannot estimate allele frequency from this information
11