In 2011, scientists investigated whether the salts that are spread on icy roads to melt the
ice are diluted enough by spring rainfall so that they do not have negative effects on
amphibian species that breed in nearby areas. They exposed clutches (groups of eggs)
of salamanders to three test conditions with varying salt concentrations (road salts
mixed with dechlorinated tap water) to simulate salt concentrations of small pools of
water located near highways that are typically fed by rainareas where salamanders often
lay their eggs. After 9 days, the scientists placed the three groups in “normal” water and
measured how much body mass the salamanders lost every 3 days for 9 days. They
chose to measure change in mass because salamanders are able to take in water, which
helps lower the chances of salamander embryos dying from freezing, disease, or
predation. The table below provides partial results of this study.
What conclusion did scientists likely draw from this study?
A) Rainy conditions may not be enough to dilute road salts that have high salt
concentrations. Therefore, salamander clutches will experience minimal physiological
damage.
B) Rainy conditions are enough to completely dilute road salts that have high salt
concentrations. Therefore, salamander clutches will not experience any permanent
physiological damage.
C) Rainy conditions are enough to completely dilute road salts that have high salt
concentrations. Therefore, salamander clutches will experience minimal physiological
damage.
D) Rainy conditions may not be enough to dilute road salts that have high salt
concentrations. Therefore, salamander clutches will face irreversible physiological
damage.
A mutation in the gene for hormone A causes it to be unable to bind to its receptor
protein. What do you predict will happen?
A) The receptor protein will not be activated and therefore will not initiate a signal
transduction pathway.
B) The receptor protein will change shape in order to bind with hormone A.
C) The water-soluble hormone molecule will not be able to pass through the
phospholipid bilayer.
D) The water-soluble hormone molecule will not be able to pass through the interstitial
fluid.
The main function of an earthworm’s gizzard is to
A) moisten food.
B) store food.
C) absorb food.
D) grind food.
In the North Pacific Ocean, two groups of the same species of killer whales (Orcinus
orca) appear to be forming two different species based on what they eat. One group eats
fish and the other eats mammals such as seals. Scientists can tell what they eat based on
their teeth, because whales that feed on fish have significantly different wear patterns.
Another difference between the two groups is in how they hunt. Whales that hunt fish
tend to travel in large pods (groups of whales) and vocalize often. Whales that hunt
seals, however, tend to travel in very small groups and vocalize very little, likely
because of the excellent hearing ability of seals. If these differences brought about
speciation, the separation would be considered
A) habitat isolation.
B) temporal isolation.
C) behavioral isolation.
D) mechanical isolation.
The sum total of a population’s use of the biotic and abiotic resources of its habitat
constitutes its
A) environment.
B) evolution.
C) range.
D) niche.
When one DNA molecule is copied to make two DNA molecules, the new DNA
contains
A) none of the parent DNA.
B) 50% of the parent DNA.
C) 75% of the parent DNA.
D) 100% of the parent DNA
What is the general function of enzymes within a cell?
A) to promote the synthesis of monomers
B) to induce chemical reactions
C) to stop chemical reactions
D) to speed up chemical reactions
Propanol and isopropanol are isomers. This means that they have
A) the same molecular formula but different chemical properties.
B) different molecular formulas but the same chemical properties.
C) the same molecular formula and the same chemical properties.
D) the same molecular formula but represent different states of the compound.
Which of the following statements about plant cell walls is false?
A) Plant cell walls consist of cellulose fibers embedded in a matrix of polysaccharides
and proteins.
B) Plant cell walls are multilayered structures.
C) Plant cell walls protect plant cells by forming an impermeable layer around the cell.
D) Wood is primarily composed of plant cell walls.
An oil may be converted into a substance that is solid at room temperature by
A) adding hydrogens, decreasing the number of double bonds in the molecules.
B) removing water, causing a dehydration synthesis reaction to occur.
C) removing hydrogens, increasing the number of double bonds in the molecules.
D) cooling it, so that double bonds form and the fats solidify.
An example of an organism that parasitizes a host plant is
A) a mycorrhizal fungus.
B) nitrogen-fixing bacteria in root nodules.
C) a Venus flytrap.
D) mistletoe.
When mothers transmit IgG to their developing child during gestation, such as in the
case of a tetanus antibody, the mothers are providing a form of _________ immunity.
A) nonspecific
B) passive
C) humoral
D) active
Some RNA molecules can function like enzymes. These particular enzymatic RNA
molecules are called
A) ribosomes.
B) mRNA.
C) ribozymes.
D) RNase.
One advantage of gas exchange in water is that
A) water can contain more oxygen than air.
B) carbon dioxide is easier to eliminate in water than in air.
C) it is easy to keep the exchange surface wet.
D) ventilating gills in water requires very little energy.
When a nursery worker pinches off the terminal buds on a young chrysanthemum plant
to make it grow bushy, which of the following plant hormones is mainly responsible for
growth of side branches?
A) an auxin
B) a gibberellin
C) a cytokinin
D) abscisic acid
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.
Divergence time estimates based on molecular clocks are
A) best interpreted with caution, since they depend on assumptions that are difficult to
test.
B) likely to be correct plus or minus a few decades.
C) usually worthless since we cannot directly observe divergence times unless we
invent a time machine.
D) more reliable than divergence dates that are based on analysis of the fossil record.
The Heimlich maneuver is performed to forcibly
A) elevate the diaphragm.
B) depress the diaphragm.
C) squeeze the ribs.
D) compress the intestines.
Prolactin is a hormone whose molecular structure has remained stable over evolutionary
time but whose hormonal role has changed dramatically in different animal species.
This is an excellent example of how evolution
A) is responsible for mutation in vertebrates.
B) occurs rapidly at the molecular level to keep up with changing environmental
influences.
C) has stayed within narrow boundaries in regard to regulation of homeostasis.
D) can both preserve unity and promote diversity.
The need for intense parental care of offspring favors mating systems that are
A) polygamous.
B) diurnal.
C) monogamous.
D) promiscuous.
Which blood vessels have the thinnest walls?
A) arterioles
B) veins
C) venules
D) capillaries
Most plants can absorb and use which of the following forms of nitrogen directly?
A) nitrite and nitrate
B) nitrate only
C) ammonium and nitrogen gas
D) nitrate and ammonium
The largest estuary in the United States is the Chesapeake Bay, which extends through
six states, including Maryland, Virginia, and Pennsylvania. The bay is one of the most
productive natural areas in the world. It is home to thousands of plants and animals,
including many commercially important species. The water of the bay is relatively
shallow. Many areas are no more than 10 feet deep, with an average depth of 30 feet.
Light penetrates the shallow water and supports the submerged plants that provide food
and shelter for the many species living in the bay ecosystem. However, like many
estuaries, the bay receives large amounts of fertilizer runoff from farms, lawns, and
wastewater treatment facilities.
Which of the following is the most probable sequence of events when fertilizer runoff
reaches the bay?
A) submerged vegetation increases, food for fish and shellfish increases, fish and
shellfish populations increase
B) phytoplankton population increases, food for fish and shellfish increases, fish and
shellfish populations increase
C) phytoplankton population increases, it blocks sunlight to submerged vegetation,
submerged vegetation dies, fish and shellfish populations decrease
D) submerged vegetation decreases, fish and shellfish feed on decaying plants,
phytoplankton feed on fish and shellfish, commercial fisheries decline
Eukaryotic chromosomes differ from prokaryotic chromosomes in that they
A) are simpler.
B) are circular in structure.
C) include fewer proteins.
D) are housed in a membrane-enclosed nucleus.
Consider the following marine community: Sea otters prey on sea urchins and therefore
help maintain a healthy sea urchin population. Sea urchins prey on kelp. By helping to
maintain viable sea urchin populations, the sea otters are also allowing enough kelp to
grow and act as a habitat for other organisms.
Suppose that a bacterial infection swept across a sea otter population and killed most
sea otters before they could reproduce. How would the marine community be affected?
A) For a period of time, there would be overpopulations of sea urchins and therefore a
decline in kelp populations.
B) For a period of time, there would be an overpopulation of kelp and therefore a
decline in sea urchins.
C) Sea otters would continue to decline until they reached extinction.
D) Kelp would become a primary predator of sea urchins.
In May 2013, a drug-resistant strain of H7N9 bird flu was discovered in China. The
implication(s) of a drug-resistant virus strain is(are)
A) that it will be difficult to eradicate.
B) that it could proliferate quickly.
C) that it should be studied carefully.
D) all of the above.
Which of the following is considered a likely explanation for the events of the
Cambrian explosion?
A) Complex predator-prey relationships and increased atmospheric oxygen levels
promoted animal diversification.
B) A great surge of volcanic activity was triggered by significant movements of the
continental plates and possibly by an asteroid impact.
C) Solar flares led to increased UV radiation intensity, which in turn promoted a high
rate of mutation. This led to rapid diversification of animals.
D) The massive growth of swamp vegetation depleted the atmosphere’s carbon dioxide
and eventually cooled the Earth’s climate.
What are the consequences if decomposers are removed from the carbon cycle?
A) Fewer carbon compounds are broken down; therefore, less CO2 is released into the
atmosphere.
B) Loss of decomposers causes an increase in CO2 levels in the atmosphere.
C) Primary consumers are not able to consume as many producers.
D) An increase in the burning of wood and fossil fuels will occur.
Which of the following statements regarding fungi is false?
A) Fungi are important decomposers in ecosystems.
B) Fungi can only break down plant material.
C) The distinctive flavor of certain cheeses is due to fungi.
D) The first antibiotic discovered came from a fungus.
A disaccharide forms when
A) two monosaccharides join by dehydration synthesis.
B) two starches join by dehydration synthesis.
C) two monosaccharides join by hydrolysis.
D) two starches join by hydrolysis.
While on a walk through a forest, you notice birds in trees, earthworms in the soil, and
fungi on plant litter on the forest floor. Based on your observations, you conclude that
each of these organisms occupies a different
A) habitat.
B) ecosystem.
C) biosphere.
D) biome.
Diabetes mellitus is a metabolic disease that is characterized by the buildup of glucose
in the blood, or hyperglycemia. Diabetes results either from the pancreas not being able
to produce the hormone insulin (type 1 diabetes) or if the body’s cells become resistant
to insulin (type 2 diabetes). Insulin is a protein that binds to receptors on cell surfaces to
allow glucose to enter the cell.
In order to manage the disease, type 1 diabetics require frequent insulin injections. Until
the 1970s, insulin was obtained from processing the pancreases of large mammals such
as cows and pigs; it was then purified for medicinal use. This all changed in the 1970s
with the advent of recombinant DNA technology, which allows scientists to insert genes
from other species into bacterial plasmids and have bacteria produce proteins from
these other species’ genes. In 1978, the gene that codes for human insulin was added to
a bacterial plasmid and bacteria were used to produce human insulin. These bacteria
acted as mini-factories that produced human insulin for type 1 diabetes patients. Today,
the production of human insulin from bacteria is commonplace and is a multibillion
dollar market for pharmaceutical companies.
In order to add the gene for human insulin to a bacterial plasmid, the DNA molecules
have to be “cut” with enzymes called restriction endonucleases and then pasted back
together with enzymes called DNA ligases. Imagine that during this process, the first
five nucleotides of the human insulin gene were accidentally cut out before it was
pasted into the bacterial plasmid. What is the most likely outcome if this plasmid was
added to bacterial cells?
A) Transcription would not take place because the RNA polymerase would not
recognize the promoter.
B) The human insulin protein would be produced as normal.
C) The human insulin protein would not be produced because the start codon is
missing.
D) The human insulin protein would be shorter than normal because it will be missing
one amino acid.
Suppose that diploid cells of the seminiferous tubules encounter errors during the cell
cycle and mitosis. This results in the primary spermatocytes having a 4n number of
chromosomes. Assuming that meiosis proceeds normally, which of the following would
betrue?
A) Sperm cells would have an n number of chromosomes.
B) Sperm cells would have a 2n number of chromosomes.
C) Secondary spermatocytes would have a 4n number of chromosomes.
D) Secondary spermatocytes would have an n number of chromosomes.
Which of the following correctly lists organisms from least complex in overall
development to most complex?
A) hydras, sponges, lobsters, clams, tunicates
B) sponges, hydras, clams, lobsters, tunicates
C) sponges, clams, lobsters, tunicates, hydras
D) clams, sponges, hydras, tunicates, lobsters