Rank the following one-base point mutations (from most likely to least likely) with
respect to their likelihood of affecting the structure of the corresponding polypeptide.
1. insertion mutation deep within an intron
2. substitution mutation at the third position of an exonic codon
3. substitution mutation at the second position of an exonic codon
4. deletion mutation within the first exon of the gene
A) 1, 2, 3, 4
B) 4, 3, 2, 1
C) 2, 1, 4, 3
D) 3, 1, 4, 2
Unripe fruits protect seeds from predation and early germination. What is the major
function of ripe fruits?
A) attracting pollinators
B) dispersing seed
C) releasing nutrients to seeds
D) keeping the seed hydrated before germination
How might a single base substitution in the sequence of a gene affect the amino acid
sequence of a protein encoded by the gene, and why?
A) Only a single amino acid could change, because the reading frame is unaffected.
B) The amino acid sequence would be substantially altered, because the reading frame
would change with a single base substitution.
C) All amino acids following the substitution would be affected, because the reading
frame would be shifted.
D) It is not possible for a single base substitution to affect protein structure, because
each codon is three bases long.
Starting from a single individual, what is the size of a population of bacteria at the end
of a two-hour time period if they reproduce by binary fission every twenty minutes?
(Assume unlimited resources and no mortality.)
A) 16
B) 32
C) 64
D) 128
How many unique gametes could be produced through independent assortment by an
individual with the genotype AaBbCCDdEE?
A) 4
B) 8
C) 16
D) 64
Which of the following must exist in a population before natural selection can act upon
that population?
A) genetic variation among individuals
B) variation among individuals caused by environmental factors
C) sexual reproduction
D) the population has predators
A 0.01 M solution of a substance has a pH of 2. What can you conclude about this
substance?
A) It is a strong acid that dissociates completely in water.
B) It is a strong base that dissociates completely in water.
C) It is a weak acid.
D) It is a weak base.
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.
If scientists are trying to use what they know about HSV to devise a means of
protecting other people from being infected, which of the following would have the best
chance of lowering the number of new cases of infection?
A) vaccinate of all persons with preexisting cases of HSV
B) interfere with new viral replication in preexisting cases of HSV
C) treat HSV lesions to shorten the breakout
D) educate people about avoiding sources of infection
Activity of various enzymes at various temperatures (a) and at various pH (b).
Which curves on the graphs may represent the temperature and pH profiles of an
enzyme taken from a bacterium that lives in a mildly alkaline hot springs at
temperatures of 70C or higher?
A) curves 1 and 5
B) curves 2 and 5
C) curves 3 and 4
D) curves 3 and 5
Compare the bacteria in the figure above in generation 1 and generation 20,000. The
bacteria in generation 1 have a greater _____.
A) efficiency at exporting glucose from the cell to the environment
B) ability to survive on simple sugars, other than glucose
C) ability to synthesize glucose from amino acid precursors
D) reliance on glycolytic enzymes
Two small, poorly drained lakes lie close to each other in a northern forest. The basins
of both lakes are composed of the same geologic substratum. One lake is surrounded by
a dense Sphagnum mat; the other is not. Compared to the pond with Sphagnum, the
pond lacking the moss mat should have _____.
A) lower numbers of bacteria
B) reduced rates of decomposition
C) reduced oxygen content
D) less-acidic water
The leading and the lagging strands differ in that _____.
A) the leading strand is synthesized in the same direction as the movement of the
replication fork, and the lagging strand is synthesized in the opposite direction
B) the leading strand is synthesized by adding nucleotides to the end of the growing
strand, and the lagging strand is synthesized by adding nucleotides to the end
C) the lagging strand is synthesized continuously, whereas the leading strand is
synthesized in short fragments that are ultimately stitched together
D) the leading strand is synthesized at twice the rate of the lagging strand
Why does ice float in liquid water?
A) The high surface tension of liquid water keeps the ice on top.
B) The ionic bonds between the molecules in ice prevent the ice from sinking.
C) Stable hydrogen bonds keep water molecules of ice farther apart than water
molecules of liquid water.
D) The crystalline lattice of ice causes it to be denser than liquid water.
If a horticulturist breeding gardenias succeeds in having a single plant with a
particularly desirable set of traits, which of the following would be her most probable
and efficient route to establishing a line of such plants?
A) Backtrack through her previous experiments to obtain another plant with the same
traits.
B) Breed this plant with another plant with much weaker traits.
C) Clone the plant.
D) Force the plant to self-pollinate to obtain an identical one.
A young dog has never had much energy. He is brought to a veterinarian for help and
she decides to conduct several diagnostic tests. She discovers that the dog’s
mitochondria can use only fatty acids and amino acids for respiration, and his cells
produce more lactate than normal. Of the following, which is the best explanation of the
dog’s condition?
A) His mitochondria lack the transport protein that moves pyruvate across the outer
mitochondrial membrane.
B) His cells cannot move NADH from glycolysis into the mitochondria.
C) His cells lack the enzyme in glycolysis that forms pyruvate.
D) His cells have a defective electron transport chain, so glucose goes to lactate instead
of to acetyl CoA.
Which of the following features of how seedless land plants get sperm to egg are the
same as for some of their algal ancestors?
A) Conjugation tubes are formed between sperm and egg cells.
B) Packets of sperm are delivered by wind to the eggs.
C) Aquatic invertebrates carry sperm to eggs.
D) Flagellated sperm swim to the eggs in a water drop.
Which of these are spore-producing structures?
A) sporophyte (capsule) of a moss
B) antheridium of a moss or fern
C) archegonium of a moss or fern
D) gametophyte of a moss
Based on their effects, which pair below would NOT be expected to be active at the
same time and place?
A) prostaglandin and nitric oxide
B) endocrine and exocrine glands
C) hormones and target cells
D) neurosecretory cells and neurotransmitters
What does it mean when we say the genetic code is redundant?
A) A single codon can specify the addition of more than one amino acid.
B) The genetic code is different for different domains of organisms.
C) The genetic code is universal (the same for all organisms).
D) More than one codon can specify the addition of the same amino acid.
Use the following information to answer the question(s) below.
Rose-picker’s disease is caused by the yeast Sporothrix schenkii (S. schenkii). The yeast
grows on the exteriors of rose-bush thorns. If a human gets pricked by such a thorn, the
yeasts can be introduced under the skin. The yeasts then assume a hyphal morphology
and grow along the interiors of lymphatic vessels until they reach a lymph node. This
often results in the accumulation of pus in the lymph node, which subsequently
ulcerates through the skin surface and then drains.
Humans have immune systems in which lymph nodes are important, because many
phagocytes and lymphocytes reside there. Given that a successful infection by S.
schenkii damages lymph nodes themselves, which of the following is most probable?
A) The hyphae secrete antibiotics, which increases the ability of the infected human to
tolerate the fungus.
B) Their conversion from yeast to hyphal morphology allows such fast growth that the
body’s defenses are at least temporarily overwhelmed.
C) Defensive cells of humans cannot detect foreign cells that are covered with cell
walls composed of cellulose.
D) Given that most fungal pathogens attack plants, human defenses are simply not
adapted to seek out and destroy fungi.
Two examples of lateral meristems in plants are _____.
A) vascular cambium, producing cork; cork cambium, producing secondary phloem
B) vascular cambium, producing secondary xylem; cork cambium, producing secondary
phloem
C) vascular cambium, producing secondary xylem; cork cambium, producing cork
D) vascular cambium, producing secondary phloem; cork cambium, producing
secondary xylem
Some cells have several nuclei per cell. How could such multinucleated cells be
explained?
A) The cell underwent repeated cytokinesis but no mitosis.
B) The cell underwent repeated mitosis with simultaneous cytokinesis.
C) The cell underwent repeated mitosis, but cytokinesis did not occur.
D) The cell had multiple S phases before it entered mitosis.
The biological clock controlling circadian rhythms must ultimately_____.
A) depend on environmental cues
B) affect gene transcription
C) stabilize on a 24-hour cycle
D) speed up or slow down with increasing or decreasing temperature
Researchers have been studying a rare population of eighty-seven voles in an isolated
area. Ten voles from a larger population were added to this isolated population. Besides
having ten additional animals, what benefits are there to importing individuals?
A) Additional animals from a distant population will likely bring genetic diversity and
reduce inbreeding depression.
B) Additional animals will bring additional competition and could hurt the population.
C) Additional animals would increase beneficial genetic drift.
D) There is no benefit other than increasing the overall population size.
The figure above represents the dynamics of _____.
A) metapopulations
B) extinction
C) emigration
D) both extinction and emigration
When two excitatory postsynaptic potentials (EPSPs) occur at a single synapse so
rapidly in succession that the postsynaptic neuron’s membrane potential has not
returned to the resting potential before the second EPSP arrives, the EPSPs add together
producing _____.
A) temporal summation
B) spatial summation
C) tetanus
D) the refractory state
It is more difficult to identify eukaryotic genes than prokaryotic genes because in
eukaryotes _____.
A) the proteins are larger than in prokaryotes
B) the coding portions of genes are shorter than in prokaryotes
C) there are no start codons
D) there are introns
Simard et al. (1997) further hypothesized that if reciprocal transfer did occur, it would
be a source-sink relationship driven by photosynthetic rates. That is, if one seedling is
in full sun and the other in deep shade, there will be a net movement of carbon from the
seedling in full sun to the one in deep shade. If a shade was placed over the birch
seedlings and the cedar, and the Douglas fir was left in full sun, what result could
Simard and colleagues expect?
A) More 13C would be found in the birch than in the Douglas fir.
B) More 13C would be found in the Douglas fir than in the birch.
C) The most 13C would be found in the cedar.
D) The most 14C would be found in the cedar.
Which of the following structures in females is analogous in function to the vas
deferens in males?
A) urethra
B) oviduct
C) uterus
D) vagina
Yeast cells are frequently used as hosts for cloning because they _____.
A) easily form colonies
B) can remove exons from mRNA
C) do not have plasmids
D) are eukaryotic cells
Which of the following statements best describes the rationale for applying the
principle of parsimony in constructing phylogenetic trees?
A) Parsimony allows the researcher to “root” the tree.
B) Similarity due to common ancestry should be more common than similarity due to
convergent evolution.
C) The molecular clock validates the principle of parsimony.
D) The outgroup roots the tree, allowing the principle of parsimony to be applied.
Which of the functional groups below acts most like an acid in water?
A) amino
B) carbonyl
C) carboxyl
D) hydroxyl
Use the following diagram of five islands formed at around the same time near a
particular mainland, as well as MacArthur and Wilson’s island biogeography principles,
to answer the question(s) below.
Which island would likely have the lowest extinction rate?
A) A
B) C
C) D
D) E
The voltage across a membrane is called the _____.
A) chemical gradient
B) membrane potential
C) osmotic potential
D) electrochemical gradient
Suppose you are provided with an actively dividing culture of E. coli bacteria to which
radioactive thymine has been added. What would happen if a cell replicates once in the
presence of this radioactive base?
A) One of the daughter cells, but not the other, would have radioactive DNA.
B) Neither of the two daughter cells would be radioactive.
C) All four bases of the DNA would be radioactive.
D) DNA in both daughter cells would be radioactive.