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Which statement represents the best explanation for the observation that the nuclear
DNA of wolves and domestic dogs has a very high degree of sequence homology?
Dogs and wolves _____.
A) have very similar morphologies
B) belong to the same order
C) are both members of the order Carnivora
D) share a very recent common ancestor
The most recently discovered phylum in the animal kingdom (1995) is the phylum
Cycliophora. It includes three species of tiny organisms that live in large numbers on
the outsides of the mouthparts and appendages of lobsters. The feeding stage
permanently attaches to the lobster via an adhesive disk and collects scraps of food
from its host's feeding by capturing the scraps in a current created by a ring of cilia. The
body is sac-like and has a U-shaped intestine that brings the anus close to the mouth.
Cycliophorans are coelomates, do not molt (though their host does), and their embryos
undergo spiral cleavage.
Which of these features is LEAST useful in assigning the phylum Cycliophora to a
clade of animals?
A) having a true coelom as a body cavity
B) having a body symmetry that permits a U-shaped intestine
C) having embryos with spiral cleavage
D) lacking ecdysis (molting)
Which of the pairs of molecular structures shown below depict enantiomers
(enantiomeric forms) of the same molecule?
A)
B)
C)
D)
In recent times, it has been shown that adult cells can be induced to become pluripotent
stem cells (iPS). To make this conversion, what has been done to the adult cells?
A) A retrovirus is used to introduce four specific regulatory genes.
B) The adult stem cells must be fused with embryonic cells.
C) Cytoplasm from embryonic cells is injected into the adult cells.
D) The nucleus of an embryonic cell is used to replace the nucleus of an adult cell.
Consider the global nitrogen cycle depicted in the figure above. How are humans
altering this cycle?
A) industrial nitrogen fixation
B) nitrogen lost to the atmosphere
C) reduction of nitrogen available to terrestrial ecosystems
D) reduction of nitrogen fixation by bacteria
It has been observed that organisms on islands are different from, but closely related to,
similar forms found on the nearest continent. This is taken as evidence that ____.
A) island forms are descended from mainland forms
B) common environments are inhabited by the same organisms
C) island forms and mainland forms have identical gene pools
D) the island forms and mainland forms are converging
Select the choice that correctly associates the organ with its embryonic sources.
A) anterior pituitary gland mesoderm and endoderm
B) thyroid gland mesoderm and ectoderm
C) adrenal gland ectoderm and mesoderm
D) skin endoderm and mesoderm
If plant gene alterations cause plants to be deficient in photorespiration, what would
most probably occur?
A) Photosynthetic efficiency would be reduced at low light intensities.
B) Cells would carry on the Calvin cycle at a much slower rate.
C) There would be more light-induced damage to the cells.
D) Less oxygen would be produced.
Looking at the figure above, what can be said about edge effects?
A) Biomass declines along edges of forest fragments.
B) Biomass increases along the edges of forest fragments.
C) Species diversity decreases along the edges of forest fragments.
D) Fragmentation does not affect biomass.
Not all intercellular signals require transduction. Which one of the following signals
would be processed without transduction?
A) a lipid-soluble signal
B) a signal that is weakly bound to a nucleotide
C) a signal that binds to a receptor in the cell membrane
D) a signal that binds to the ECM
The electrons of photosystem II are excited and transferred to electron carriers. From
which molecule or structure do the photosystem II replacement electrons come?
A) the electron carrier, plastocyanin
B) photosystem I
C) water
D) oxygen
In multiple sclerosis the myelin sheaths around the axons of the brain and spinal cord
are damaged and demyelination results. How does this disease manifest at the level of
the action potential?
I) Action potentials move in the opposite direction on the axon.
II) Action potentials move more slowly along the axon.
III) No action potentials are transmitted.
A) only I
B) only II
C) only III
D) only II and III
Which of the following would be considered an example of bioremediation?
A) adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen
availability
B) using a bulldozer to regrade a strip mine
C) dredging a river bottom to remove contaminated sediments
D) adding seeds of a chromium-accumulating plant to soil contaminated by chromium
If humans had been present to build log structures during the Carboniferous period
(they were not), which plant types would have been suitable sources of logs?
A) horsetails and bryophytes
B) lycophytes and bryophytes
C) ferns, horsetails, and lycophytes
D) charophytes (stoneworts), bryophytes, and gymnosperms
The following experiment is used for the corresponding question(s).
A researcher discovered a species of moth that lays its eggs on oak trees. Eggs are laid
at two distinct times of the year: early in spring when the oak trees are flowering and in
midsummer when flowering is past. Caterpillars from eggs that hatch in spring feed on
oak flowers and look like oak flowers. But caterpillars that hatch in summer feed on
oak leaves and look like oak twigs.
How does the same population of moths produce such different-looking caterpillars on
the same trees? To answer this question, the biologist caught many female moths from
the same population and collected their eggs. He put at least one egg from each female
into eight identical cups. The eggs hatched, and at least two larvae from each female
were maintained in one of the four temperature and light conditions listed below.
In each of the four environments, one of the caterpillars was fed oak flowers, the other
oak leaves. Thus, there were a total of eight treatment groups (4 environments x 2
diets).
Refer to the accompanying figure. In every case, caterpillars that feed on oak flowers
look like oak flowers. In every case, caterpillars that were raised on oak leaves looked
like twigs. These results support which of the following hypotheses?
A) The longer day lengths of summer trigger the development of twig-like caterpillars.
B) Differences in air pressure, due to elevation, trigger the development of different
types of caterpillars.
C) Differences in diet trigger the development of different types of caterpillars.
D) The differences are genetic. A female will either produce all flowerlike caterpillars
or all twig-like caterpillars.
The generative cell of male angiosperm gametophytes is haploid. This cell divides to
produce two haploid sperm cells. What type of cell division does the generative cell
undergo to produce these sperm cells?
A) mitosis
B) meiosis
C) mitosis without subsequent cytokinesis
D) meiosis without subsequent cytokinesis
An elementary school science teacher decided to liven up the classroom with a
saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher
proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided
to stock the tank with various marine invertebrates, including a polychaete, a siliceous
sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial
hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod
varieties. Lastly, she added some vertebratesa parrotfish and a clownfish. She arranged
for daily feedings of copepods and feeder fish.
The clownfish readily swims among the tentacles of the sea anemones; the parrotfish
avoids them. One hypothesis for the clownfish's apparent immunity is that they slowly
build a tolerance to the sea anemone's toxin. A second hypothesis is that a chemical in
the mucus that coats the clownfish prevents the nematocysts from being triggered.
Which of the following graphs supports the second, but not the first, of these
hypotheses?
A)
B)
C)
D)
Halobacterium has a photosynthetic membrane that appears purple. Its photosynthetic
action spectrum is the inverse of the action spectrum for green plants. (That is, the
Halobacterium action spectrum has a peak where the green plant action spectrum has a
trough.) What wavelengths of light do the Halobacterium photosynthetic pigments
absorb?
A) red and yellow
B) blue, green, and red
C) green and yellow
D) blue and red
Double fertilization means that_____.
A) flowers must be pollinated twice to yield fruits and seeds
B) one sperm is needed to fertilize the egg, and a second sperm is needed to fertilize the
polar nuclei
C) the egg of the embryo sac is diploid
D) every sperm has two nuclei
How does inefficient transfer of energy among trophic levels result in the typically high
endangerment status of many top-level predators?
A) Top-level predators are destined to have small populations that are sparsely
distributed.
B) Predators have relatively large population sizes.
C) Predators are more disease-prone than animals at lower trophic levels.
D) Top-level predators are more likely to be stricken with parasites.
Cells were infected with approximately 1000 copies of either virus A or virus B at the 0
time point. At five-minute intervals, a sample of the virus and cell mixture was
removed. The intact cells were removed from the sample, and the number of viruses per
milliliter of culture was determined.
Using the data in the figure above, how long does it take for virus A to go through one
lytic cycle?
A) 15 minutes
B) 30 minutes
C) 45 minutes
D) 90 minutes
An individual who has been bitten by a poisonous snake that has a fast-acting toxin
would likely benefit from _____.
A) vaccination with a weakened form of the toxin
B) injection of antibodies to the toxin
C) injection of interleukin-1
D) injection of interferon
The "threshold" potential of a membrane is the _____.
A) lowest frequency of action potentials a neuron can produce
B) minimum hyperpolarization needed to prevent the occurrence of action potentials
C) minimum depolarization needed to operate the voltage-gated sodium and potassium
channels
D) peak amount of depolarization seen in an action potential
What can proteomics reveal that genomics cannot?
A) the number of genes characteristic of a species
B) the patterns of alternative splicing
C) the set of proteins present within a cell or tissue type
D) the movement of transposable elements within the genome
The Brazil nut tree, Bertholletia excels (n = 17), is native to tropical rain forests of
South America. It is a hardwood tree that can grow to over 50 meters tall, is a source of
high-quality lumber, and is a favorite nesting site for harpy eagles. As the rainy season
ends, tough-walled fruits, each containing 8-25 seeds (Brazil nuts), fall to the forest
floor. Brazil nuts are composed primarily of endosperm. About $50 million worth of
nuts are harvested each year. Scientists have discovered that the pale yellow flowers of
Brazil nut trees cannot fertilize themselves and admit only female orchid bees as
pollinators. The agouti (Dasyprocta spp.), a cat-sized rodent, is the only animal with
teeth strong enough to crack the hard wall of Brazil nut fruits. It typically eats some of
the seeds, buries others, and leaves still others inside the fruit, which moisture can now
enter. The uneaten seeds may subsequently germinate.
If a female orchid bee has just left a Brazil nut tree with nectar in her stomach, and if
she visits another flower on a different Brazil nut tree, what is the sequence in which
the following events should occur?
1. double fertilization
2. pollen tube emerges from pollen grain
3. pollen tube enters micropyle
4. pollination
A) 4, 2, 3, 1
B) 4, 3, 2, 1
C) 2, 4, 3, 1
D) 2, 4, 1, 3
You are looking through a microscope at a slide of animal tissue and see a single layer
of flat, closely packed cells that cover a surface. This specific tissue is most likely
_____.
A) adipose
B) a tendon
C) epithelial
D) a neuron
Which of the listed statements describes the results of the following reaction?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
A) C6H12O6 is oxidized and O2 is reduced.
B) O2 is oxidized and H2O is reduced.
C) CO2 is reduced and O2 is oxidized.
D) O2 is reduced and CO2 is oxidized.
Which of the following would increase the rate of heat exchange between an animal
and its environment?
A) feathers or fur
B) vasoconstriction
C) wind blowing across the body surface
D) blubber or fat layer
Which of the following statements is FALSE?
A) Carbon, hydrogen, oxygen, and nitrogen are the most abundant elements of living
matter.
B) Some naturally occurring elements are toxic to organisms.
C) All life requires the same essential elements.
D) Iron is needed by all humans.
According to the lac operon model proposed by Jacob and Monod, what is predicted to
occur if the operator is removed from the operon?
A) The lac operon would be transcribed continuously.
B) Only lacZ would be transcribed.
C) Only lacY would be transcribed.
D) Galactosidase permease would be produced, but would be incapable of transporting
lactose.
Which of the following is the most predictable outcome of increased gene flow between
two populations?
A) lower average fitness in both populations
B) higher average fitness in both populations
C) increased genetic difference between the two populations
D) decreased genetic difference between the two populations
H. V. Wilson worked with sponges to gain some insight into exactly what was
responsible for holding adjacent cells together. He exposed two species of differently
pigmented sponges to a chemical that disrupted the cell-cell interaction (cell junctions),
and the cells of the sponges dissociated. Wilson then mixed the cells of the two species
and removed the chemical that caused the cells to dissociate. Wilson found that the
sponges reassembled into two separate species. The cells from one species did not
interact or form associations with the cells of the other species. How do you explain the
results of Wilson's experiments?
A) The two species of sponge had different enzymes that functioned in the reassembly
process.
B) The molecules responsible for cell-cell adhesion (cell junctions) were irreversibly
destroyed during the experiment.
C) The molecules responsible for cell-cell adhesion (cell junctions) differed between the
two species of sponge.
D) One cell functioned as the nucleus for each organism, thereby attracting only cells of
the same pigment.
