Two students studying physiology taste a known “bitter” substance, and both report
sensing bitterness. They then sample another substance. Student A reports sensing both
a bitter taste and a salty taste, but student B reports only a salty taste. What is the most
logical explanation?
A) Student A had an allergic reaction to the food, causing him to perceive the food as
being bitter.
B) Student A has normal “bitter” taste buds; student B has defective “bitter” taste buds
that result in lower sensitivity to bitterness.
C) Student A has a protein receptor capable of detecting a bitter molecule found in that
substance, whereas student B lacks that particular protein receptor.
D) Student A has normal saliva, whereas student B’s saliva is more alkaline than
normal.
A newborn who is accidentally given a drug that destroys the thymus would most likely
_____.
A) lack innate immunity
B) be unable to genetically rearrange antigen receptors
C) be unable to differentiate and mature T cells
D) have a reduced number of B cells and be unable to form antibodies
A researcher has used in vitro mutagenesis to mutate a cloned gene and then has
reinserted the mutated gene into a cell. To have the mutated sequence disable the
function of the gene, what must then occur?
A) recombination resulting in replacement of the wild type with the mutated gene
B) use of a microarray to verify continued expression of the original gene
C) replication of the cloned gene using a bacterial plasmid
D) transcription of the cloned gene using a BAC
The following questions are based on the accompanying figure.
In the figure above, MPF reaches its highest concentration during this stage.
A) I
B) II
C) III
D) IV
A researcher took water in which a Jl population had been thriving, filtered the water to
remove all bacterial cells, and then applied the water to the skins of adult amphibians to
see if there would subsequently be a reduced infection rate by Bd when frog skins were
inoculated with Bd. For which of the following hypotheses is the procedure described a
potential test?
A) the hypothesis that a toxin secreted by Jl cells kills Bd cells when both are present
together on frog skin
B) the hypothesis that Jl cells infect and kill Bd cells when both are present together on
frog skin
C) the hypothesis that Jl outcompetes Bd when both are present together on a frog’s skin
D) the hypothesis that the presence of Jl on frog skin causes a skin reaction that
prevents attachment by Bd cells
A major function of magnesium in plants is to be _____.
A) required to regenerate phosphoenolpyruvate in C4 and CAM plants
B) a component of DNA and RNA
C) a component of chlorophyll
D) active in amino acid formation
An excretory system that is partly based on the filtration of fluid under high hydrostatic
pressure is the _____.
A) flame bulb system of flatworms
B) protonephridia of rotifers
C) Malpighian tubules of insects
D) kidneys of vertebrates
Evidence that parthenogenic whiptail lizards are derived from sexually reproducing
ancestors includes _____.
A) the requirement for male-like behaviors in some females before their partners will
ovulate
B) the development and then regression of testes prior to sexual maturation
C) the observation that all of the offspring are haploid
D) the persistence of a vestigial penis among some of the females
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. Consequently, “flower of
stone’should be expected to possess which other characteristics?
1. a gametophyte generation that is dominant
2. lignified vascular tissues
3. microphylls
4. filamentous rhizoids, but not true roots
5. spores that are diploid when mature
A) 1 and 2
B) 1 and 5
C) 2 and 3
D) 3, 4, and 5
Insect hormones and their receptors _____.
A) act independently of each other
B) are a focus in pest control research
C) utilize cell-surface receptors only
D) are active independently of environmental cues
Fred and Joe, two unrelated, mature male gorillas, encounter one another. Fred is
courting a female. Fred grunts as Joe comes near. As Joe continues to advance, Fred
begins drumming (pounding his chest) and bares his teeth. Joe then rolls on the ground
on his back, gets up, and quickly leaves. This behavioral pattern is repeated several
times during the mating season. Choose the most specific behavior described by this
example.
A) agonistic behavior
B) territorial behavior
C) learned behavior
D) fixed action pattern
The questions below refer to the following description and figure.
The figure below represents a cross section of the sea floor through a mid-ocean rift
valley, with alternating patches of black and white indicating sea floor with reversed
magnetic polarities. At the arrow labeled “I” (the rift valley), the igneous rock of the sea
floor is so young that it can be accurately dated using carbon-14 dating. At the arrow
labeled “III,” however, the igneous rock is about one million years old, and
potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows
indicate the direction of sea-floor spreading, away from the rift valley.
Assuming that the rate of sea-floor spreading was constant during the one-million-year
period depicted above, on average Earth’s magnetic field has undergone reversal once
every _____.
A) 25,000 years
B) 100,000 years
C) 250,000 years
D) 1,000,000 years
Which of the following describes the events of apoptosis?
A) The cell dies, it is lysed, its organelles are phagocytized, and its contents are
recycled.
B) The cell’s DNA and organelles become fragmented, the cell dies, and it is
phagocytized.
C) The cell’s DNA and organelles become fragmented, the cell shrinks and forms blebs,
and the cell’s parts are packaged in vesicles that are digested by specialized cells.
D) The cell’s nucleus and organelles are lysed, then the cell enlarges and bursts.
A virus consisting of a single strand of RNA, which is transcribed into complementary
DNA, is a _____.
A) protease
B) retrovirus
C) RNA replicase virus
D) nonenveloped virus
The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still
possesses a cell wall. What is likely to be true of this species?
1. It is a bacterium.
2. It is an archaean.
3. The optimal pH of its enzymes will lie above pH 7.
4. The optimal pH of its enzymes will lie below pH 7.
5. It could inhabit certain hydrothermal springs.
6. It could inhabit alkaline hot springs.
A) 1, 3, and 6
B) 2, 4, and 5
C) 1, 3, and 5
D) 1, 4, and 5
Which of the following is most likely true of a protein that cotransports glucose and
sodium ions into the intestinal cells of an animal?
A) Sodium and glucose compete for the same binding site in the cotransporter.
B) Glucose entering the cell down its concentration gradient provides energy for uptake
of sodium ions against the electrochemical gradient.
C) Sodium ions can move down their electrochemical gradient through the
cotransporter whether or not glucose is present outside the cell.
D) A substance that blocks sodium ions from binding to the cotransport protein will also
block the transport of glucose.
The first gap in the cell cycle (G1) corresponds to _____.
A) normal growth and cell function
B) the phase in which DNA is being replicated
C) the beginning of mitosis
D) the phase between DNA replication and the M phase
Which of the following characteristics evolved independently in mammals and birds?
A) amniotic eggs
B) jaws
C) bone
D) endothermy
What happens if twice as many inhibitory postsynaptic potentials (IPSPs) as excitatory
postsynaptic potentials (EPSPs) arrive at a postsynaptic neuron in close proximity?
A) A stronger action potential results.
B) A weaker action potential results.
C) No action potential results.
An eccentric millionaire botanist has offered a $25,000 scholarship to anyone who can
successfully get a plant to grow through a vertical maze in complete darkness. The
maze is not in a box; the maze is simply drawn on the wall, and the contestants must get
their plant to grow in a pattern that matches the path through the maze. You need the
money and feel confident that you can accomplish this task. Which of the following
techniques will help you succeed?
A) Apply auxin directly to the shoot tip on the side to which you want the tip to bend.
B) Apply auxin directly to the part of the stem just below the tip opposite from the
direction you want the stem to bend.
C) Inject compounds that block auxin receptors into the part of the stem opposite from
the direction you want the stem to bend.
D) Plant the roots in two different pots, and apply auxin to the root bucket that is on the
same side as the direction you want the plant to bend.
Most causes of speciation are relatively slow, in that they may take many generations to
see changes, with the exception of _____.
A) polyploidy
B) reinforcement
C) colonization
D) natural selection
Use the following information to answer the question(s) below.
The herpes viruses are important enveloped DNA viruses that cause disease in
vertebrates and in some invertebrates such as oysters. Some of the human forms are
herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the
varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three
actively infects nervous tissue. Primary infections are fairly mild, but the virus is not
then cleared from the host; rather, viral genomes are maintained in cells in a latent
phase. The virus can later reactivate, replicate again, and infect others.
In electron micrographs of HSV infection, it can be seen that the intact virus initially
reacts with cell surface proteoglycans, then with specific receptors. This is later
followed by viral capsids docking with nuclear pores. Afterward, the capsids go from
being full to being “empty.” Which of the following best fits these observations?
A) Viral capsids are needed for the cell to become infected; only the capsids enter the
nucleus.
B) The viral envelope is not required for infectivity, since the envelope does not enter
the nucleus.
C) Only the genetic material of the virus is involved in the cell’s infectivity, and is
injected like the genome of a phage.
D) The viral envelope mediates entry into the cell, the capsid mediates entry into the
nuclear membrane, and the genome is all that enters the nucleus.
The fru gene in fruit flies _____.
I) controls sex-specific development in the fruit fly
II) is a master regulatory gene that directs expression of many other genes
III) can be genetically manipulated in females so that they will perform male sex
behaviors
IV) programs males for appropriate courtship behaviors
A) only I and III
B) only II and IV
C) only II, III, and IV
D) I, II, III, and IV
A solution contains 0.0000001 (10-7) moles of hydroxyl ions [OH-] per liter. Which of
the following best describes this solution?
A) acidic: H+ acceptor
B) basic: H+ acceptor
C) acidic: H+ donor
D) neutral
The evolution of animal species has been prolific (the estimates go into the millions and
tens of millions). Much of this diversity is a result of the evolution of novel ways to
_____.
A) reproduce
B) arrange cells into tissues
C) sense, feed, and move
D) form an embryo and establish a basic body plan
Which category in the figure above makes available the highest productivity per square
meter?
A) tropical wet forest
B) open ocean
C) algal beds and reefs
D) wetlands
The reason that the steroid hormone aldosterone affects only a small number of cells in
the body is that _____.
A) only its target cells get exposed to aldosterone
B) only its target cells contain aldosterone receptors
C) it is unable to enter nontarget cells
D) nontarget cells destroy aldosterone before it can produce any effect
A billionaire buys a sterile volcanic island that recently emerged from the sea. To speed
the arrival of conditions necessary for plant growth, the billionaire might be advised to
aerially sow what over the island?
A) basidiospores
B) spores of ectomycorrhizae
C) soredia
D) yeasts
Which of the following structures are correctly paired?
A) forebrain cerebellum
B) midbrain cerebrum
C) hindbrain cerebellum
D) brainstem anterior pituitary gland
Which of the following is a defining characteristic that all protocells had in common?
A) the ability to synthesize enzymes
B) a surrounding membrane or membrane-like structure
C) RNA genes
D) the ability to replicate RNA
A biologist doing a long-term study on a wild spider population observes increased
variation in silk thickness. Which of the following could the spider population be
experiencing?
A) directional selection
B) stabilizing selection
C) disruptive selection
D) genetic drift