If you think of the earthworm body plan as a drinking straw within a pipe, where would
you expect to find most of the tissues that developed from endoderm?
A) lining the straw
B) lining the space between the pipe and the straw
C) forming the outside of the pipe
D) forming the outside of the straw
Which of the following is true for this reaction?
A) The reaction is nonreversible.
B) Hydrogen and nitrogen are the reactants of the reverse reaction.
C) Ammonia is being formed and decomposed simultaneously.
D) Only the forward or reverse reactions can occur at one time.
In testing a hypothesis that “territorial defense in European robins is a fixed action
pattern that is released by the sight of orange feathers,” researchers found that robins
defended their territory by attacking anything that was of similar size and had an orange
patch. What experiment would you perform next to determine that the color initiated the
defense response?
A) Repeat the experiment using a blue patch instead of an orange patch.
B) Repeat the experiment by removing the patch completely.
C) Repeat the experiment by using a model of a robin that was twice the size of a
normal robin but with a small orange patch.
D) Repeat the experiment by using a model of a robin that had an orange patch that was
twice the size of a normal patch.
Which of the following processes within viral replication is the greatest source of
genetic variation in RNA virus populations?
A) High mutation rate due to lack of proofreading of RNA genome replication errors.
B) Transcription from the host cell RNA polymerase introduces numerous mutations.
C) Capsid proteins from the host cell can replace the viral capsid.
D) Viral RNA is translated by host cell ribosomes.
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.
Entrepreneurs attempted, but failed, to harvest nuts from plantations grown in Southeast
Asia. Attempts to grow Brazil nut trees in South American plantations also failed. In
both cases, the trees grew vigorously, produced healthy flowers in profusion, but set no
fruit. Consequently, what is the likely source of the problem?
A) poor sporophyte viability
B) failure to produce fertile ovules
C) failure to produce pollen
D) pollination failure
Fossil evidence indicates that the following events occurred in what sequence, from
earliest to most recent?
1. Protostomes invade terrestrial environments.
2. Cambrian explosion occurs.
3. Deuterostomes invade terrestrial environments.
4. Vertebrates become top predators in the seas.
A) 2 → 1 → 4 → 3
B) 2 → 4 → 1 → 3
C) 2 → 3 → 1 → 4
D) 2 → 1 → 3 → 4
Red-cheeked salamanders are partially protected from predators because of cardiac
glycosides they produce from glands on their back. When ingested, cardiac glycosides
disrupt normal heart rhythms. A different salamander species, the imitator salamander,
also has red cheek patches, but does not produce cardiac glycosides. It does gain
protection from predators that have learned to avoid red cheeked salamanders. How
does this relationship affect the population dynamics of both species?
A) Both species are negatively affected.
B) Both species are positively affected.
C) The red cheeked salamander is positively affected, the imitator is negatively
affected.
D) The red cheeked salamander is negatively affected, the imitator is positively
affected.
Liverworts, hornworts, and mosses are grouped together as the Bryophytes. Besides not
having vascular tissue, what do they all have in common?
A) They are all wind pollinated.
B) They are heterosporous.
C) They can reproduce asexually by producing gemmae.
D) They require water for reproduction.
Subtropical plants are commonplace in Land’s End, England, whose latitude is the
equivalent of Labrador in coastal Canada, where the local flora is subarctic. Which
statement best explains why this apparent anomaly exists between North America and
Europe?
A) Labrador does not get enough rainfall to support the subtropical flora found in
Land’s End.
B) Warm ocean currents interact with England, whereas cold ocean currents interact
with Labrador.
C) Rainfall fluctuates greatly in England; rainfall is consistently high in Labrador.
D) Labrador receives sunlight of lower duration and intensity than does Land’s End.
A vasectomy _____.
A) eliminates spermatogenesis
B) eliminates testosterone synthesis
C) prevents implantation of an embryo
D) prevents sperm from exiting the male urethra
Jaws first occurred in which extant group of fishes?
A) lampreys
B) chondrichthyans
C) ray-finned fishes
D) placoderms
Why has C. elegans proven to be a useful model for understanding apoptosis?
A) The animal does not naturally use apoptosis, but can be induced to do so in the
laboratory.
B) The nematode undergoes a fixed and easy-to-visualize number of apoptotic events
during its normal development.
C) This plant has a long-studied aging mechanism that has made understanding its
death just a last stage.
D) While the organism ages, its cells die progressively until the whole organism is
dead.
An example of an ectothermic organism that has few or no behavioral options when it
comes to its ability to adjust its body temperature is a _____.
A) sea star living deep in the ocean
B) bass living in a farm pond
C) hummingbird flying through a prairie
D) honeybee in a hive on a rural farm
Centromeres split and sister chromatids migrate to opposite poles in meiosis _____.
A) anaphase I
B) telophase I
C) anaphase II
D) telophase II
To adjust blood pressure independently in the capillaries of the gas-exchange surface
and in the capillaries of the general body circulation, an organism would need a(n)
_____.
A) open circulatory system
B) hemocoel
C) two-chambered heart
D) four-chambered heart
Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a
gene on the human X chromosome. The patients have muscles that weaken over time
because they have absent or decreased dystrophin, a muscle protein. They rarely live
past their twenties. How likely is it for a woman to have this condition?
A) Women can never have this condition.
B) One-fourth of the daughters of an affected man would have this condition.
C) One-half of the daughters of an affected father and a carrier mother could have this
condition.
D) Only if a woman is XXX could she have this condition.
Tadpoles must undergo a major metamorphosis to become frogs. This change includes
reabsorption of the tail, growth of limbs, calcification of the skeleton, increase in
rhodopsin in the eye, development of lungs, change in hemoglobin structure, and
reformation of the gut from the long gut of an herbivore to the short gut of a carnivore.
Amazingly, all of these changes are induced by thyroxine. What is the most likely
explanation for such a wide array of effects of thyroxine?
A) There are many different forms of thyroxine, each specific to a different tissue.
B) Different tissues have thyroxine receptors that activate different signal transduction
pathways.
C) Some tissues have membrane receptors for thyroxine, while other tissues have
thyroxine receptors within the nucleus.
D) Different releasing hormones release thyroxine to different tissues.
Upon closer inspection of the leaves of “flower of stone,” one can observe tiny,
cone-like structures. Each cone-like structure emits spores of two different sizes.
Further investigation also reveals that the roots of “flower of stone” branch only at the
growing tip of the root, forming a Y-shaped structure. Based on these additional
observations, which of the following can be properly inferred about “flower of stone”?
1. It is heterosporous.
2. It is a fern.
3. The cone-like structures are sori.
4. It is a lycophyte.
5. It has separate male and female gametophytes.
A) 1 and 5
B) 2 and 3
C) 1, 2, and 3
D) 1, 4, and 5
In 1986, a nuclear power accident in Chernobyl, USSR (now Ukraine), led to high
radiation levels for miles surrounding the plant. The high levels of radiation caused
elevated mutation rates in the surviving organisms, and evolutionary biologists have
been studying rodent populations in the Chernobyl area ever since. Based on your
understanding of evolutionary mechanisms, which of the following most likely
occurred in the rodent populations following the accident?
A) Mutations caused major changes in rodent physiology over time.
B) Mutation led to increased genetic variation.
C) Mutation caused genetic drift and decreased fitness.
D) Mutation caused the fixation of new alleles.
Which of the life cycles is typical for plants and some algae?
A) I only
B) II only
C) III only
D) I and III
A population is correctly defined as having which of the following characteristics?
I) inhabiting the same general area
II) belonging to the same species
III) possessing a constant and uniform density and dispersion
A) III only
B) I and II only
C) II and III only
D) I, II, and III
In the pressure-flow mechanism, loading of sucrose from companion cells to sieve-tube
elements takes place through _____.
A) plasmodesmata
B) facilitated diffusion
C) sucrose-H+ symporters
D) sucrose-H+ antiporters
During metamorphosis, a tadpoles tail is reduced in size by the process of _____.
A) regeneration
B) apoptosis
C) oxidative phosphorylation
D) re-differentiation
Motor proteins provide for molecular motion in cells by interacting with what types of
cellular structures?
A) membrane proteins of the inner nuclear envelope
B) free ribosomes and ribosomes attached to the ER
C) components of the cytoskeleton
D) cellulose fibers in the cell wall
The concentrations of ions are very different inside and outside a nerve cell due to
_____.
A) osmosis
B) diffusion
C) sodium-potassium pumps
D) symports and antiports
The highest amount of oxygen will be found in soils containing large amounts of
_____.
A) clay
B) sand
C) gravel
D) silt
Why is terrestrial productivity higher in equatorial climates?
A) Productivity increases with temperature.
B) Productivity increases with water availability.
C) Productivity increases with available sunlight.
D) The answer is most likely a combination of the other responses.
A group of cells is assayed for DNA content immediately following mitosis and is
found to have an average of 8 picograms of DNA per nucleus. How many picograms
would be found at the end of S and the end of G2?
A) 8; 8
B) 8; 16
C) 16; 8
D) 16; 16
Female birds lay their eggs, thereby facilitating flight by reducing weight. Which
‘strategy” seems most likely for female bats to use to achieve the same goal?
A) limit litters to a single embryo
B) refrain from flying throughout pregnancy (about six weeks long)
C) give birth to underdeveloped young, and subsequently carry them in a pouch that has
teats
D) feed multiple embryos internally using placentas
As N approaches K for a certain population, which of the following is predicted by the
logistic equation?
A) The growth rate will not change.
B) The growth rate will approach zero.
C) The population will increase exponentially.
D) The carrying capacity of the environment will increase.
Orchid seeds are tiny, with virtually no endosperm and with miniscule cotyledons. If
such seeds are deposited in a dark, moist environment, then which of the following
represents the most likely means by which fungi might assist in seed germination, given
what the seeds lack?
A) by transferring some chloroplasts to the embryo in each seed
B) by providing the seeds with water and minerals
C) by providing the embryos with some of the organic nutrients they have absorbed
D) by strengthening the seed coat that surrounds each seed
How many electron pairs does carbon share to complete its valence shell?
A) 2
B) 3
C) 4
D) 8
Hyphae form a covering over roots. These hyphae create a large surface area that helps
to do which of the following?
A) aid in absorbing minerals and ions
B) maintain cell shape
C) increase cellular respiration
D) anchor a plant