If global warming continues at its present rate, which biomes will likely take the place
of the coniferous forest (taiga)?
A) temperate broadleaf forest and grassland
B) desert and chaparral
C) tropical forest and savanna
D) chaparral and temperate broadleaf forest
Which statement best describes what ultimately happens to the chemical energy that is
not converted to new biomass in the process of energy transfer between trophic levels in
an ecosystem?
A) It is undigested and winds up in the feces and is not passed on to higher trophic
levels.
B) It is used by organisms to maintain their life processes through the reactions of
cellular respiration.
C) Heat produced by cellular respiration is used by heterotrophs for thermoregulation.
D) It is eliminated as feces or is dissipated into space as heat, consistent with the second
law of thermodynamics.
Saturated fatty acids _____.
A) have double bonds between carbon atoms of the fatty acids
B) are the principal molecules in lard and butter
C) are usually liquid at room temperature
D) are usually produced by plants
A man who is an achondroplastic dwarf with normal vision marries a color-blind
woman of normal height. The man’s father was six feet tall, and both the woman’s
parents were of average height. Achondroplastic dwarfism is autosomal dominant, and
red-green color blindness is X-linked recessive. What proportion of their sons would be
color-blind and of normal height?
A) none
B) half
C) one out of four
D) all
Testosterone is an example of a chemical signal that affects the very cells that
synthesize it, the neighboring cells in the testis, along with distant cells outside the
gonads. Thus, testosterone is an example of _____.
I) an autocrine signal
II) a paracrine signal
III) an endocrine signal
A) only I and II
B) only II and III
C) only I and III
D) I, II, and III
If you were using cladistics to build a phylogenetic tree of cats, which of the following
would be the best outgroup?
A) lion
B) domestic cat
C) wolf
D) leopard
Which of the three types of viruses shown above would you expect to include
glycoproteins?
A) I only
B) II only
C) III only
D) I and II only
Consider the food chain of grass → grasshopper → mouse → snake → hawk. About
how much of the chemical energy fixed by photosynthesis of the grass (100 percent) is
available to the hawk?
A) 0.01%
B) 0.1%
C) 1%
D) 10%
Which of the following is an example of a commensalism?
A) fungi residing in plant roots, such as endomycorrhizae
B) bacteria fixing nitrogen in plants
C) rancher ants that protect aphids in exchange for sugar-rich honeydew
D) cattle egrets eating insects stirred up by grazing bison
The figure above represents tRNA that recognizes and binds a particular amino acid (in
this instance, phenylalanine). Which codon on the mRNA strand codes for this amino
acid?
A) UGG
B) GUG
C) GUA
D) UUC
A noncompetitive inhibitor decreases the rate of an enzyme reaction by _____.
A) binding at the active site of the enzyme
B) changing the shape of the enzyme’s active site
C) changing the free energy change of the reaction
D) acting as a coenzyme for the reaction
Which of the following are functions of rhizobacteria?
I) produce hormones that stimulate plant growth
II) produce antibiotics that protect roots from disease
III) absorb toxic metals
IV) carry out nitrogen fixation
A) only II and IV
B) only I, II, and III
C) only III and IV
D) I, II, III, and IV
Which of the following types of reactions would decrease the entropy within a cell?
A) anabolic reactions
B) hydrolysis
C) digestion
D) catabolic reactions
Oxytocin and antidiuretic hormone (ADH) are synthesized in the _____.
A) hypothalamus
B) adenohypophysis
C) anterior pituitary
D) posterior pituitary
What is a major difference between eukaryotic DNA replication and prokaryotic DNA
replication?
A) Prokaryotic replication does not require a primer.
B) Prokaryotic chromosomes have a single origin of replication, while eukaryotic
chromosomes have multiple origins of replication.
C) DNA replication in prokaryotic cells is conservative. DNA replication in eukaryotic
cells is semi-conservative.
D) DNA polymerases of prokaryotes can add nucleotides to both and ends of DNA
strands, while those of eukaryotes function only in the → direction.
Which of the following amino acids are most frequently phosphorylated by protein
kinases in the cytoplasm during signal transduction?
A) tyrosines
B) glycine and histidine
C) serine and threonine
D) glycine and glutamic acid
Hawaii is the most southeastern of the seven largest islands and is also closest to the
sea-floor spreading center from which the Pacific plate originates, which lies about
5600 km further to the southeast. Assuming equal sedimentation rates, what should be
the location of the thickest sediment layer and, thus, the area with the greatest diversity
of fossils above the oceanic crust?
A) between the island of Hawaii and the sea-floor spreading center
B) around the base of the island of Hawaii
C) around the base of Kauai, the oldest of the large Hawaiian islands
D) where the islands are most concentrated (highest number of islands per unit surface
area)
After surgical removal of an infected gallbladder, a person must be especially careful to
restrict dietary intake of _____.
A) protein
B) sugar
C) fat
D) water
Among mammals, the male and female genital structures that consist mostly of erectile
tissue include the _____.
A) penis and clitoris
B) vas deferens and oviduct
C) testes and ovaries
D) prostate and ovaries
During mammalian labor and delivery, the contraction of uterine muscles is enhanced
by oxytocin. This is an example of _____.
A) a negative feedback system
B) a hormone that acts in an antagonistic way with another hormone
C) a hormone that is involved in a positive feedback loop
D) signal transduction immediately changing gene expression in its target cells
Which of the following is characteristic of the lytic cycle?
A) Viral DNA is incorporated into the host genome.
B) The viral genome replicates without destroying the host.
C) A large number of phages are released at a time.
D) The virushost relationship usually lasts for generations.
Evidence suggests that factors which contribute towards the virulence of E. coli strain
O157:H7, a bacterial strain reported to cause several food poisoning deaths, are caused
by genes from a virus that infects bacteria. Considering this evidence, which statement
most likely explains how the O157:H7 population acquired the genetic variation that
distinguishes the strain from harmless E. coli strains, such as those that reside in our
intestines?
A) The virus entered the bacterial cell and incorporated its DNA into the bacterial
genome, allowing the bacteria’s cellular machinery to create new viruses.
B) Viral envelope proteins bind to receptors on the bacterial membrane, allowing the
viral genetic material to enter the bacterium and become translated into proteins.
C) The virus entered the cell and acquired specific genes from the bacteria to increase
the virulence of the virus.
D) The virus infected the bacterium, and allowed the bacterial population to replicate
with a copy of the phage genome in each new bacterium.
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, which of the
following is the closest living relative of “flower of stone”?
A) true moss
B) club moss
C) liverwort
D) fern
Mendel’s observation of the segregation of alleles in gamete formation has its basis in
which of the following phases of cell division?
A) prophase I of meiosis
B) anaphase II of meiosis
C) metaphase II of meiosis
D) anaphase I of meiosis
A graded hyperpolarization of a membrane can be induced by _____.
A) increasing its membrane’s permeability to Na+
B) decreasing its membrane’s permeability to Cl–
C) increasing its membrane’s permeability to Ca++
D) increasing its membrane’s permeability to K+
When the atoms involved in a covalent bond have the same electronegativity, what type
of bond results?
A) an ionic bond
B) a hydrogen bond
C) a nonpolar covalent bond
D) a polar covalent bond
When climbing a mountain, we can observe transitions in biological communities that
are analogous to the changes _____.
A) in biomes at different latitudes
B) in a community through different seasons
C) in an ecosystem as it evolves over time
D) across the United States from east to west
Use the following information to answer the question(s) below.
Scarlet gilia (Ipomopsis aggregata) usually has red flowers in an inflorescence of up to
250 flowers. In certain populations in the Arizona mountains, however, the flowers
range from red to pink to white. In early summer, most of the flowers were red. Six to
eight weeks later, the same individual plants were still present; the flowers ranged from
pink to white, and few red flowers were present. The major pollinators early in the
season were two species of hummingbirds active during the day; they emigrated to
lower elevations, and the major pollinator later in the season was a hawk moth (a type
of moth). The hawk moth was most active at sunset and later, and it preferred light pink
to white flowers after dark. When hummingbirds were present, more red flowers than
white flowers produced fruit. When only hawk moths were present, more white flowers
produced fruit (K. N. Paige and T. G. Whitham. 1985. Individual and population shifts
in flower color by scarlet gilia: A mechanism for pollinator tracking. Science
227:315-17).
Refer to the paragraph on scarlet gilia. What is the significance of measuring fruit
production?
A) It is a measure of pollination success.
B) It is a measure of seed dispersal success.
C) It is easier than counting flowers.
D) It is an indication of predation on the seeds of the plants.
Why do Na+ ions enter the cell when voltage-gated Na+ channels are opened in
neurons?
A) because the Na+ concentration is much lower outside the cell than it is inside
B) because the Na+ ions are actively transported by the sodium-potassium pump into
the cell
C) because the Na+ concentration is much higher outside the cell than it is inside, and
the Na+ ions are attracted to the negatively charged interior
D) because the Na+ concentration is much higher outside the cell than it is inside, and
the Na+ ions are actively transported by the sodium-potassium pump into the cell
A toxin that binds specifically to voltage-gated sodium channels in axons would be
expected to _____.
A) prevent the hyperpolarization phase of the action potential
B) prevent the depolarization phase of the action potential
C) prevent graded potentials
D) increase the release of neurotransmitter molecules
According to the theory of sea-floor spreading, oceanic islands, such as the Hawaiian
Islands depicted in the figure above, form as oceanic crustal plates move over a
stationary “hot spot” in the mantle. Currently, the big island of Hawaii is thought to be
over a hot spot, which is why it is the only one of the seven large islands that has active
volcanoes. What should be true of the island of Hawaii?
1. Scientists in search of ongoing speciation events are more likely to find them here
than on the other six large islands.
2. Its species should be more closely related to those of nearer islands than to those of
farther islands.
3. It should have a rich fossil record of terrestrial organisms.
4. It should have species that are not found anywhere else on Earth.
5. On average, it should have fewer species per unit surface area than the other six
islands.
A) 1, 2, and 3
B) 1, 2, and 5
C) 1, 2, 3, and 4
D) 1, 2, 4, and 5
Oxygen has an atomic number of 8 and most commonly, a mass number of 16. Thus,
what is the atomic mass of an oxygen atom?
A) approximately 8 grams
B) approximately 8 daltons
C) approximately 16 grams
D) approximately 16 daltons
The shell of a fertilized animal egg has what type of analog in angiosperms?
A) endosperm
B) carpels
C) fruit
D) seed coat