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1. The term "gene expression" refers to the
a. fact that each individual of a species has a unique set of genes.
b. fact that individuals of the same species have different phenotypes.
c. process by which genetic information flows from genes to proteins.
d. flow of information from parent to offspring.
2. Which of the following mechanisms of controlling gene expression occurs outside of the nucleus?
a. adding a cap and tail to RNA
b. DNA packing/unpacking
c. RNA splicing
d. Translation
3. A gene operon consists of
a. a transcribed gene only.
b. a promoter only.
c. a regulatory gene only.
d. transcribed genes, an operator, and a promoter.
4. In plants, most differentiated cells retain
a. only a tiny fraction of their original set of genes.
b. a complete set of their genes but lose the ability to express most of those genes.
c. a complete set of their genes and retain the ability to express those genes under certain circumstances.
d. the ability to dedifferentiate but then cannot return to their original differentiated state.
5. A gene that can cause cancer when present in a single copy in a cell is called a(n)
a. oncogene.
b. enhancer gene.
c. carcinogen.
d. proto-oncogene.
6. Which of the following is not a factor that contributes to normal cells becoming cancerous?
a. the conversion of a proto-oncogene to an oncogene
b. damage to a tumor-suppressor gene
c. the production of more effective tumor-suppressor gene products
d. excessive replication of proto-oncogenes
7. The development of colon cancer occurs slowly, and colon cancer is more frequently seen in the elderly than the
young. This is most likely because
a. cancer cells don't have mitochondria, so they grow slowly.
b. usually six or more somatic mutations must occur to give rise to the cancer, which takes time.
c. cancer cells have to wait until new blood vessels grow into the area, which takes much time.
d. most cancer mutations interfere with mitosis, so cell division occurs more slowly.
8. There is a mutation in a promoter next to a gene such that RNA polymerase can never bind. What steps must
occur for the gene to be transcribed?
a. An activator protein must bind an enhancer.
b. The DNA must physically bend so that the activator is close to the promoter.
c. Transcription factors must bind to the activator and promoter.
d. Transcription will never take place in this specific example.
9. Speciation, or the formation of new species, is
a. a form of microevolution.
b. responsible for the diversity of life.
c. necessary for natural selection and adaptation.
d. an event that has occurred only a few times in the history of the planet.
10. Speciation without geographic isolation is called ________ speciation.
a. sympatric
b. allopatric
c. incomplete
d. diversifying
11. Which of the following would a biologist describe as microevolution?
a. the formation of new species
b. the extinction of species
c. dramatic biological changes, such as the origin of flight, within a taxon
d. a change in the gene pool of a population from one generation to the next
12. Microevolution, or evolution at its smallest scale, occurs when
a. an individual's traits change in response to environmental factors.
b. a community of organisms changes due to the extinction of several dominant species.
c. a new species arises from an existing species.
d. a population's allele frequencies change over a span of generations
13. Under the biological species concept, a species is a group of organisms that
a. are physically similar.
b. share a recent common ancestor.
c. live together in a location and carry out identical ecological roles.
d. have the potential to interbreed in nature and produce fertile offspring.
14. Which of the following types of reproductive barriers separates a pair of insect species that could interbreed but
for the fact that one lives on goldenrod plants and the other on autumn daisies in the same general area?
a. temporal isolation
b. habitat isolation
c. behavioral isolation
d. gametic isolation
15. Two species that occasionally mate and produce zygotes, but that have incompatible genes that prevent the
resulting embryo from developing, are affected by
a. gametic isolation.
b. reduced hybrid fertility.
c. reduced hybrid viability.
d. hybrid breakdown.
16. Which of the following types of reproductive barriers separates two flowering plant species that could interbreed
but for the fact that one has a deep flower tube and is pollinated by bumblebees whereas the other has a short,
narrow flower tube and is pollinated by honeybees?
a. habitat isolation
b. behavioral isolation
c. mechanical isolation
d. gametic isolation
17. Cancer of the colon is caused by
a. a single somatic cell gene mutation.
b. several somatic cell gene mutations.
c. a physical rupture of the colon.
d. a diet high in fiber and low in fat.
18. A stomach cell is producing pepsin, an enzyme that hydrolyzes proteins. Which of the following events suggests
that gene expression of pepsin has been turned off in the cell?
a. The pepsin protein is folded properly in the cytoplasm.
b. The chromosome with the pepsin gene is tightly coiled.
c. The pepsin mRNA leaves the nucleus and enters the cytoplasm.
d. None of the above
19. In terms of gene regulation, what do eukaryotes and prokaryotes have in common?
a. operons such as the lac operon and the trp operon
b. elaborate packing of DNA into chromosomes
c. activator proteins that bind to DNA
d. promoters that bind RNA polymerases
20. Which of the following statements regarding skin cells and muscle cells in your body is true?
a. Muscle cells contain information about muscle proteins but not about skin color.
b. Skin cells contain information skin color but not about muscle proteins.
c. Muscle cells contain information about skin color but not about muscle proteins.
d. Skin cells and muscle cells each contain information about both muscle proteins and skin
21. The lac operon in Escherichia coli
a. prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.
b. prevents lactose intolerance.
c. prevents lactose-utilizing enzymes from being expressed when lactose is present in the environment.
d. promotes the expression of lactose-utilizing enzymes when lactose is absent from the environment.
22. The tortoiseshell pattern on a cat
a. usually occurs in males.
b. is the result of a homozygous recessive condition.
c. results from X chromosome inactivation.
d. is a result of alleles on the Y chromosome.
23. Which of the following best expresses the concept of natural selection?
a. differential reproductive success based on inherited characteristics
b. inheritance of acquired characteristics
c. change in response to need
d. a process of constant improvement, leading eventually to perfection
24. The recessive allele of a gene causes cystic fibrosis. For this gene among Caucasians, p = 0.98. If a Caucasian
population is in Hardy-Weinberg equilibrium with respect to this gene, what proportion of babies is born
homozygous recessive and therefore suffers cystic fibrosis?
a. (0.02)2 = 0.0004
b. 0.02
c. (0.98)2 = 0.9604
d. 2(0.02 × 0.98) = 0.0392
25. The frequency of homozygous dominant individuals in a population that is in Hardy-Weinberg equilibrium is
equal to
a. q or p
b. p2
c. 2pq
d. 2p
26. An elk herd is observed over many generations. Most of the full-grown bull elk have antlers of nearly the same
size, although a few have antlers that are significantly larger or smaller than this average size. The average antler
size remains constant over the generations. Which of the following effects probably accounts for this situation?
a. directional selection
b. stabilizing selection
c. a bottleneck effect that resulted in low genetic diversity
d. a high rate of gene flow
27. Imagine that you are studying a very large population of moths that is isolated from gene flow. A single gene
controls wing color. Half of the moths have white-spotted wings (genotype WW or Ww) and half of the moths
have plain brown wings (ww). There are no new mutations, individuals mate randomly, and there is no natural
selection on wing color. How will p, the frequency of the dominant allele, change over time?
a. p will increase; the dominant allele will eventually take over and become most common in the population.
b. p will neither increase nor decrease; it will remain more or less constant under the conditions described.
c. p will decrease because of genetic drift.
d. p will fluctuate rapidly and randomly because of genetic drift.
28. A rabbit population consists of animals that are either very dark on top or very light on top. The color pattern is
not related to sex. No rabbit shows intermediate coloration (medium darkness). This pattern might result from
____________ selection.
a. disruptive
b. directional
c. stabilizing d. sexual
29. Mothers and teachers often say they need another pair of eyes on the backs of their heads. And another pair of
hands would come in handy in many situations. You can imagine that these traits would have been advantageous
to our early hunter-gatherer ancestors as well. According to sound evolutionary reasoning, what is the most likely
explanation for why humans do not have these traits?
a. Because they actually would not be beneficial to the fitness of individuals who possessed them. Natural
selection always produces the most beneficial traits for a particular organism in a particular environment.
b. Because every time they have arisen before, the individual mutants bearing these traits have been killed
by chance events. Chance and natural selection interact.
c. Because these variations have probably never appeared in a healthy human. As tetrapods, we are pretty
much stuck with a four-limbed, two-eyed body plan; natural selection can only edit existing variations.
d. Because humans are a relatively young species. If we stick around and adapt for long enough, it is
inevitable that the required adaptations will arise.
30. A farmer decides to go into the business of raising trout for tourists who enjoy fishing. She builds six trout ponds
and stocks each of them with trout from genetically identical stock. Her friends tell her that because she started
each pond with just a few trout, she has created a bottleneck effect and her trout populations are likely to become
genetically different rapidly. Which of the following statements about her trout is likely true?
a. Because they are all genetically alike, they will all remain alike even though the ponds are different.
b. Because each population started off with just a few individuals, every mutation that occurs will have a
huge impact on the population, so they are likely to evolve in different directions quickly.
c. Because the ponds are different and the populations are likely to experience different mutations, the
populations will likely diverge evolutionarily, but only over many generations.
d. The increase in genetic diversity caused by sexual reproduction will promote evolutionary divergence
over time.
31. The pattern of distribution for a certain species of kelp is clumped. The pattern of distribution for a population of
snails that live on the kelp would be
a. clumped.
b. homogeneous.
c. random.
d. uniform.
32. The maximum number of individuals a habitat can support is called its
a. reproductive potential.
b. carrying capacity.
c. community size.
d. density-dependent factor.
33. A newly mated queen ant establishes an ant nest in an unoccupied patch of suitable habitat. The population of the
nest grows quickly at first, then levels off at carrying capacity. Which of the following models best describes its
population growth?
a. linear
b. logarithmic
c. logistic
d. exponential
34. If an ecosystem has a carrying capacity of 1,000 individuals for a given species and 2,000 individuals of that
species are present, we can predict that the population
a. size will remain at equilibrium.
b. size will decrease.
c. will show a clumped dispersion pattern.
d. size will slowly increase.
35. An r-selected species typically
a. offers considerable parental care to offspring.
b. has an advantage in habitats that experience unpredictable disturbances.
c. is large-bodied and long-lived.
d. lives in stable climates.
36. A Type I survivorship curve is associated with which of the following life history traits?
a. parents providing extended care for their young
b. large numbers of offspring being produced
c. infant mortality being much greater than adult mortality
d. a short life span for most individuals
37. What kind of curve represents exponential growth?
a. ascending straight line
b. J-shaped
c. S-shaped
d. descending straight line