Download Practice Exam 4

Practice Exam 4
Below are sample questions from your book (all the answers are in the back). These are not
necessarily indicative of the specific material or types of questions that Dr. Raich will ask on the
exam. Remember, he wants you to be able to apply our knowledge of the material learned in class
and from the book and part of that comes from understanding the significance, application, and
importance of that information. Good luck!!
1. In which phase of the cell cycle are chromosomes replicated?
a. G1 phase
b. S phase
c. M phase
d. G2 phase
e. none of the above
2. If two chromosomes are homologous, they
a. look similar under the microscope.
b. have very similar DNA sequences.
c. carry the same types of genes.
d. may carry different versions of the same gene.
e. are all of the above.
3. Checkpoints during the cell cycle are important because they
a. allow the organelle activity to catch up to cellular demands.
b. ensure the integrity of the cell's DNA.
c. allow the cell to generate sufficient ATP for cellular division.
d. are the only time DNA replication can occur.
e. do all of the above.
4. Which of the following is a reason for mitotic cell division?
a. asexual reproduction
b. gamete formation in animals
c. multicellularity
d. all of the above
e. both a and c
5. A replicated chromosome is composed of
a. two homologous chromosomes held together at the centromere.
b. four sister chromatids held together at the centromere.
c. two sister chromatids held together at the centromere.
d. four homologous chromosomes held together at the centromere.
e. one chromosome with a centromere.
6. Which of the following is not an event of anaphase of mitosis?
a. The nuclear envelope breaks down.
b. Sister chromatids separate.
c. Kinetochore microtubules shorten, pulling the chromosomes to the pole.
d. Polar microtubules push against each other, moving the poles farther apart.
e. All of the above occur during anaphase.
7. A student is looking at cells under the microscope. The cells are from an organism that has a diploid
number of 14. In one particular case, the cell has seven replicated chromosomes (sister chromatids)
aligned at the metaphase plate of the cell. Which of the following statements accurately describes
this particular cell?
a. The cell is in metaphase of mitosis.
b. The cell is in metaphase of meiosis I.
c. The cell is in metaphase of meiosis II.
d. All of the above are correct.
e. Both b and c are correct.
8. Which of the following statements accurately describes a difference between mitosis and meiosis?
a. Mitosis may produce diploid cells, whereas meiosis produces haploid cells.
b. Homologous chromosomes synapse during meiosis but do not synapse during mitosis.
c. Crossing over commonly occurs during meiosis, but it does not commonly occur during
mitosis.
d. All of the above are correct.
e. Both a and c are correct.
9. During crossing over in meiosis I,
a. homologous chromosomes are not altered.
b. homologous chromosomes exchange genetic material.
c. chromosomal damage occurs.
d. genetic information is lost.
e. cytokinesis occurs.
10. Aneuploidy may be the result of
a. duplication of a region of a chromosome.
b. inversion of a region of a chromosome.
c. nondisjunction during meiosis.
d. interspecies breeding.
e. all of the above.
11. Based on Mendel's experimental crosses, what is the expected F 2 phenotypic ratio of a
monohybrid cross?
a. 1:2:1
b. 2:1
c. 3:1
d. 9:3:3:1
e. 4:1
12. During which phase of cellular division does Mendel's law of segregation physically occur?
a. mitosis
b. meiosis I
c. meiosis II
d. all of the above
e. b and c only
13. An individual that has two different alleles of a particular gene is said to be
a. dihybrid.
b. recessive.
c. homozygous.
d. heterozygous.
e. hemizygous.
14. Which of Mendel's laws cannot be observed in a monohybrid cross?
a. segregation
b. dominance/recessiveness
c. independent assortment
d. codominance
e. All of the above can be observed in a monohybrid cross.
15. During a cross, an individual with the dominant phenotype and unknown genotype is crossed with
a individual to determine the unknown genotype.
a. monohybrid, homozygous recessive
b. dihybrid, heterozygous
c. test, homozygous dominant
d. monohybrid, homozygous dominant
e. test, homozygous recessive
16. A woman is heterozygous for an X-linked trait, hemophilia A. If she has a child with a man without
hemophilia A, what is the probability that the child will be a male with hemophilia A? (Note: The child
could be a male or female.)
a. 100%
b. 75%
c. 50%
d. 25%
e. 0%
17. A gene that affects more than one phenotypic trait is said to be
a. dominant.
b. wild type.
c. dihybrid.
d. pleiotropic.
e. heterozygous.
18. A hypothetical flowering plant species produces red, pink, and white flowers. To determine the
inheritance pattern, the following crosses were conducted with the results indicated:
red × red → all red
white × white → all white
red × white → all pink
What type of inheritance pattern does this represent?
a. dominance/recessiveness
b. X-linked
c. codominance
d. incomplete dominance
e. pleiotropy
19. Genes located on a sex chromosome are said to be
a. X-linked.
b. dominant.
c. hemizygous.
d. sex linked.
e. sex influenced.
20. A nonbald male has an offspring with a woman who is homozygous for the pattern baldness allele.
What is the probability that the offspring will become bald?
a. 100%
b. 75%
c. 50%
d. 25%
e. 0%
21. The prebiotic soup was
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23.
24.
25.
26.
27.
28.
a. the assemblage of unicellular prokaryotes and eukaryotes that existed in the oceans of
early Earth.
b. the accumulation of organic molecules in the oceans of early Earth.
c. the mixture of organic molecules that was found in the cytoplasm of the earliest cells on
Earth.
d. a pool of nucleic acids that contained the genetic information for the earliest organisms.
e. none of the above.
Which of the following is not a characteristic of protobionts that was necessary for the evolution of
living cells?
a. a membrane-like boundary separating the external environment from an internal
environment
b. polymers capable of functioning in information storage
c. polymers capable of enzymatic activity
d. self-replication
e. compartmentalization of metabolic activity
RNA is believed to be the first functional macromolecule in protobionts because it
a. is easier to synthesize compared to other macromolecules.
b. has the ability to store information, self-replicate, and perform enzymatic activity.
c. is the simplest of the macromolecules commonly found in living cells.
d. All of the above are correct.
e. a and c only are correct.
The movement of landmasses that have changed their positions, shapes, and association with
other landmasses is called
a. glaciation.
b. Pangaea.
c. continental drift.
d. biogeography.
e. geological scale.
Paleontologists estimate the dates of fossils by
a. the layer of rock in which the fossils are found.
b. analysis of radioisotopes found in nearby rock.
c. the complexity of the body plan of the organism.
d. all of the above.
e. a and b only.
The fossil record does not give us a complete picture of the history of life because
a. not all past organisms have become fossilized.
b. only organisms with hard skeletons can become fossilized.
c. fossils of very small organisms have not been found.
d. fossils of early organisms are located too deep in the crust of the Earth to be found.
e. all of the above.
The endosymbiosis hypothesis explaining the evolution of eukaryotic cells is supported by
a. DNA-sequencing analysis comparing bacterial genomes, mitochondrial genomes, and
eukaryotic nuclear genomes.
b. naturally occurring examples of endosymbiotic relationships between bacterial cells and
eukaryotic cells.
c. the presence of DNA in mitochondria and chloroplasts.
d. all of the above.
e. a and b only.
Which of the following explanations of the evolution of multicellularity in eukaryotes is seen in the
development of complex, multicellular organisms today?
29.
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35.
a. endosymbiosis
b. aggregation of cells to form a colony
c. division of cells with the resulting cells sticking together
d. multiple cell types aggregating to form a complex organism
e. none of the above
The earliest fossils of vascular plants were formed during the period.
a. Ordovician
b. Silurian
c. Devonian
d. Triassic
e. Jurassic
The appearance of the first hominoids date to the period.
a. Triassic
b. Jurassic
c. Cretaceous
d. Tertiary
e. Quaternary
A change in one or more characteristics of a population that is heritable and occurs from one
generation to the next is called
a. natural selection.
b. sexual selection.
c. population genetics.
d. evolution.
e. inheritance of acquired characteristics.
Lamarck's vision of evolution differed from Darwin's in that Lamarck believed
a. living things evolved in an upward direction.
b. behavioral changes modified heritable traits.
c. genetic differences among individuals in the population allowed for evolution.
d. a and b only.
e. none of the above.
Which of the following scientists influenced Darwin's views on the nature of population growth?
a. Cuvier
b. Malthus
c. Lyell
d. Hutton
e. Wallace
An evolutionary change in which an organism's characteristics change in ways that make it better
suited to its environment is
a. natural selection.
b. an adaptation.
c. an acquired characteristic.
d. evolution.
e. both a and c.
Vestigial structures are anatomical structures
a. that have more than one function.
b. that were functional in an ancestor but no longer have a useful function.
c. that look similar in different species but have different functions.
d. that have the same function in different species but have very different appearances.
e. of the body wall.
36. Which of the following is an example of a developmental homology seen in human embryonic
development and other vertebrate species that are not mammals?
a. gill ridges
b. umbilical cord
c. tail
d. both a and c
e. all of the above
37. Two or more homologous genes found within a particular species are called
a. homozygous.
b. orthologs.
c. paralogs.
d. alleles.
e. duplicates.
38. The phenomenon of exon shuffling
a. creates new gene products by changing the pattern of intron removal in pre-mRNA.
b. creates new genes by inserting exons and flanking introns into a different gene
sequence, thereby introducing a new domain in the gene product.
c. deletes one or more bases in a single gene.
d. rearranges the introns in a particular gene, creating new gene products.
e. both a and d.
39. Horizontal gene transfer
a. is a process in which an organism incorporates genetic material from another organism
without being the offspring of that organism.
b. can involve the exchange of genetic material among individuals of the same species.
c. can involve the exchange of genetic material among individuals of different species.
d. can be all of the above.
e. can be a and b only.
40. Genetic variation can occur as a result of
a. random mutations in genes.
b. exon shuffling.
c. gene duplication.
d. horizontal gene transfer.
e. all of the above.
41. Population geneticists are interested in the genetic variation in populations. The most common
type of genetic change that can cause polymorphism in a population is
a. a deletion of a gene sequence.
b. a duplication of a region of a gene.
c. a rearrangement of a gene sequence.
d. a single-nucleotide substitution.
e. an inversion of a segment of a chromosome.
42. The Hardy-Weinberg equation characterizes the genotype frequencies and allele frequencies
a. of a population that is experiencing selection for mating success.
b. of a population that is extremely small.
c. of a population that is very large and not evolving.
d. of a community of species that is not evolving.
e. of a community of species that is experiencing selection.
43. Considering the Hardy-Weinberg equation, what portion of the equation would be used to
calculate the frequency of individuals that do not exhibit a disease but are carriers of a recessive
genetic disorder?
a. q
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b. p2
c. 2pq
d. q2
e. both b and d
By itself, which of the following is not likely to have a major impact on allele frequencies?
a. natural selection
b. genetic drift
c. mutation
d. inbreeding
e. both c and d
Which of the following statements is correct regarding mutations?
a. Mutations are not important in evolution.
b. Mutations provide the source for genetic variation, but other evolutionary factors are more
important in determining allele frequencies in a population.
c. Mutations occur at such a high rate that they promote major changes in the gene pool
from one generation to the next.
d. Mutations are insignificant when considering evolution of a large population.
e. Mutations are of greater importance in larger populations than in smaller populations.
In a population of fish, body coloration varies from a light shade, almost white, to a very dark
shade of green. If changes in the environment resulted in decreased predation of individuals with
the lightest coloration, this would be an example of selection.
a. diversifying
b. stabilizing
c. directional
d. sexual
e. artificial
Considering the same population of fish described in question 6, if the stream environment
included several areas of sandy, light-colored bottom areas and a lot of dark-colored vegetation,
both the light- and dark-colored fish would have selective advantage and increased survival. This
type of scenario could explain the occurrence of
a. genetic drift.
b. diversifying selection.
c. mutation.
d. stabilizing selection.
e. sexual selection.
The microevolutionary factor most sensitive to population size is
a. mutation.
b. migration.
c. selection.
d. genetic drift.
e. all of the above.
The neutral theory of evolution differs from Darwinian evolution in that
a. neutral theory states that natural selection does not exist.
b. neutral theory states that most of the genetic variation in a population is due to neutral
mutations, which do not affect reproductive success.
c. neutral variation alters survival and reproductive success.
d. neutral mutations are not affected by population size.
e. both b and c.
Populations that experience inbreeding may also experience
a. a decrease in fitness due to an increased frequency of recessive genetic diseases.
b.
c.
d.
e.
an increase in fitness due to increases in heterozygosity.
very little genetic drift.
no apparent change.
increased mutation rates.