Practice Exam 3
1.) Through a microscope, you can see a cell wall beginning to develop arcoss the middle
of the cell and the nuclei re-forming an either side of the cell wall. The cell is most likely:
a. an animal cell in the process of cytokinesis
b. a plant cell in the process of cytokinesis
c. a bacterial cell dividing
d. an animal cell in the S phase of the cell cycle
e. a plant cell in metaphase
2.) A particular cell has half as much DNA as some other cells in mitotically active
tissues. The cell in question is most likely in:
a. G1
b. G2
c. prophase
d. metaphase
e.anaphase
3.) In some organisms, mitosis occurs without cytokinesis occurring. This would result
in:
a. cells with more than one nucleus
b. cells that are unusually small
c. cells lacking nuclei
d. destruction of chromosomes
e. cells lacking S phase
4.) Mitosis is important because:
a. cells that wear out and die need to be replaced b. it produces genetically identical cells
c. some organisms use it to reproduce asexually d. all of the above are true
5.) 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
6.) Homologous chromosomes move toward opposite poles of a dividing cell during:
a. mitosis
b. meiosis I c. meiosis II d. fertilization
e. binary fission
7.) 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
8.) 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
9.) 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
10.) If you studied a cell through an electron microscope and found that it had a large
number of mitochondria, which of the following is a logical conclusion?
a. it is dividing
b. it cannot have a nucleus or cell wall
c. it is a bacterial cell
d. it could not be a plant cell
e. none of the above
11.) 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
12.) 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
13.) 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
14.) The ABO blood types in humans is an example of:
a. multiple alleles
b. epistasis
c.pleiotrophy
d. polygenic inheritance
15.) ___________ 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
c. polygenic inheritance: epistasis
d. epistasis; pleiotrophy
16.) Trisomy 21 is an example of:
a. Polyploidy
b. Triploidy
c. Aneuploidy
d. Tetraploidy
17.) 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
18.) Which of the following is not an observation or inference on which natural selection
is based?
a. There is heritable variation among individuals.
b. Poorly adapted individuals never produce offspring.
c. There is a struggle for limited resources, and only a fraction of offspring will survive
d. Individuals whose characteristics are best suited to the environment generally leave
more offspring than those whose characteristics are less well studied.
e. Organisms interact with their environment.
19.) The smallest biological unit that can evolve over time is:
a. a cell
b. an individual organism c. a species
d. a population e. an ecosystem
- In the notes, it says that populations evolve over time, not individuals. Also, it says that
evolution is a population phenomenon. The definition of a population is a localized group
of individuals that belong to the same biological species that are capable of interbreeding
or potentially interbreeding. In Dr. Dolphin’s lecture on Null-Evolutionary Processes it
says that microevolution is the change in allelic frequencies within a population’s gene
pool over successive generations. Also, I found another website at another school that
said the population is the smallest biological unit that can evolve.
( http://www.chaffey.edu/biology/avila/lectures/Outline_Microevolution.pdf)
20.) A geneticist mixed together many different kinds of fruit flies- some with long
wings, some with short wings, some with red eyes, and some with brown eyes. 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 red eyes,
and most of the extreme types disappeared. This illustrates:
a. stabilizing selection
b. diversifying selection
c. fitness
d. genetic
drift
21.) 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%
22.) Bullocks Oriole and the Baltimore Oriole are closely related, but to determine if they
are the same species they should:
a. sing similar songs
b. successfully interbreed c. look alike d. live in the same
area
23.) 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
24.) The largest unit within which gene flow can readily occur is a
a. population
b. species
c. genus
d. hybrid
e. phylum
25) Plant species A has a diploid number of 12. Plant species B has a diploid number of
16. A new species, C, arisis, as an allopolyploid from A and B. They likely diploid
number for C is
a. 12
b. 14
c. 16
d. 28
e.56
26.) The speciation episode described in question 25 is most likely a case of
a. allopatric speciation
b. sympatric speciation
c. speciation based on sexual selection
d. adaptive selection
e. anagenesis
27.) A genetic change that caused a certain Hox gene to be expressed along the tip of a
vertebrate ling bud instead of father back made possible the evolution of the tetrapod
limb. This type of change is illustrative of
a. the influence of the environment on an individual’s development
b. paedomorphosis, or retention of ancestral juvenile structures in an adult organism
c. a change in a developmental gene or in its regulation that altered the spatial
organization of body parts.
d. punctuated equilibrium
e, the origin of new species due to allopolyploidy
28.) All of the following important concepts of population genetics are due to random
events or chance except:
a. mutation
b. the founder effect
c. sexual recombination
d. natural selection
29.) Most copies of harmful recessive alleles in a population are carried by individuals
that are:
a. haploid
b. polymorphic
c. homozygous for the allele
d. heterozygous for the allele
e. affected with the disorder caused by the allele
30.) Sister chromatids:
a. are created when DNA is replicated
b. are attached at the centromere prior to division
c. are separated during mitosis
d. have matching copies of the chromosome’s DNA
e. All of the above
*** This practice exam is just a random mix of questions that does not match the
breakdowns of each lecture that Dr. Dolphin gave in class. It is just some topics that I
thought were very important. Do not just study the topic on this practice exam. You need
to go over your notes many times, and read the text book to further understand all the
material.