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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.
For the enzyme- catalyzed reaction shown in the figure, if the initial reactant
concentration is 1.0 micromolar, which of these treatments will cause the greatest
increase in the rate of the reaction?
A) doubling the activation energy needed
B) cooling the reaction by 10oC
C) doubling the enzyme concentration
D) increasing the concentration of reactants to 10.0 micromolar, while reducing the
concentration of enzyme by 1/2
Which of the following is the best explanation for why vegetable oil is a liquid at room
temperature while animal fats are solid?
A) Vegetable oil has more double bonds than animal fats.
B) Vegetable oil has fewer double bonds than animal fats.
C) Animal fats have no amphipathic character.
D) Vegetable oil has longer fatty-acid tails than animal fats have.
Which of the following is an example of potential rather than kinetic energy?
A) water rushing over Niagara Falls
B) light flashes emitted by a firefly
C) a molecule of glucose
D) a crawling beetle foraging for food
The following questions are based on the reaction A+ B ↔C+ Dshown in the
accompanying figure.
Which of the following represents the activation energy required for the
enzyme-catalyzed reaction in the figure?
A) a
B) b
C) c
D) d
During a field trip, an instructor touched a moth resting on a tree trunk. The moth raised
its forewings to reveal large eyespots on its hind wings. The instructor asked why the
moth lifted its wings. One student answered that sensory receptors had fired and
triggered a neuronal reflex culminating in the contraction of certain muscles. A second
student responded that the behavior might frighten predators. Which statement best
describes these explanations?
A) The first explanation is correct, but the second is incorrect.
B) The first explanation refers to proximate causation, whereas the second refers to
ultimate causation.
C) The first explanation is testable as a scientific hypothesis, whereas the second is not.
D) Both explanations are reasonable and simply represent a difference of opinion.
Which of the following evidence most strongly supports the common origin of all life
on Earth? All organisms _____.
A) require energy
B) use essentially the same genetic code
C) reproduce
D) show heritable variation
Which of the following is generally true of aneuploidies in newborns?
A) A monosomy is more frequent than a trisomy.
B) Monosomy X is the only viable monosomy known to occur in humans.
C) Human aneuploidy usually conveys an adaptive advantage in humans.
D) An aneuploidy resulting in the deletion of a chromosome segment is less serious
than a duplication.
What is the reason that closely linked genes are typically inherited together?
A) They are located close together on the same chromosome.
B) The number of genes in a cell is greater than the number of chromosomes.
C) Alleles are paired together during meiosis.
D) Genes align that way during metaphase I of meiosis.
Allosteric enzyme regulation is usually associated with _____.
A) feedback inhibition
B) activating activity
C) an enzyme with more than one subunit
D) the need for cofactors
Brown et al. and Morwood et al. reported in 2004 that they had found skeletal remains
of a previously unknown type of hominin, now dubbed Homo floresiensis, on the
Indonesian island of Flores. These hominins were small (approximately 1 meter tall)
with small braincases (approximately 380 cubic centimeters) as compared with other
hominins. The remains of H. floresiensis were found alongside handmade stone tools
and the remains of dwarf elephants that also inhabited the island, suggesting that H.
floresiensis was able both to make tools and to coordinate the hunting of animals much
larger than itself. H. floresiensis is estimated to have lived at the site where the remains
were found from at least 38,000 years ago to 18,000 years ago.
Refer to the paragraph on Brown et al. and Morwood et al. Which would be the most
feasible method of figuring out to which other hominin species H. floresiensis was most
closely related?
A) Compare the type of prey hunted by H. floresiensis to that hunted by each of the
other hominin species.
B) Compare the average body size of H. floresiensis to that of each of the other hominin
species.
C) Compare the skeletal morphology of H. floresiensis to that of each of the other
hominin species.
D) Compare the estimated life span of H. floresiensis to that of each of the other
hominin species.
Umami perception would be stimulated by _____.
A) chocolate milk
B) a slice or roast beef
C) acidic orange juice
D) salt water
Immediately after putting on a shirt, your skin might feel itchy. However, this
perception soon fades due to _____.
A) sensory adaptation
B) accommodation
C) reduced motor unit recruitment
D) reduced receptor amplification
Which of the following would be inhibited by a drug that specifically blocks the
addition of phosphate groups to proteins?
A) G protein-coupled receptor binding
B) ligand-gated ion channel signaling
C) adenylyl cyclase activity
D) receptor tyrosine kinase activity
Use the following diagram showing the spread of the cattle egret, Bubulcus ibis, since
its arrival in the New World, to answer the question below.
The range of cattle egrets has expanded between 1937 and today. How would an
ecologist likely explain the expansion of the cattle egret?
A) Climatic factors, such as temperature and precipitation, provide a suitable habitat for
cattle egrets.
B) There are no predators for cattle egrets in the New World, so they continue to expand
their range.
C) A habitat left unoccupied by native herons and egrets met the biotic and abiotic
requirements of the cattle egret transplants and their descendants.
D) The first egrets to colonize South America evolved into a new species capable of
competing with the native species of herons and egrets.
Bioinformatics can be used to scan for short sequences that specify known mRNAs,
called _____.
A) expressed sequence tags
B) multigene families
C) proteomes
D) short tandem repeats
Which of the following is a representation of gene density?
A) Humans have 2900 Mb per genome.
B) C. elegans has ~20,000 genes.
C) Humans have ~20,000 protein-encoding genes in 2900 Mb.
D) Fritillaria has a genome 40 times the size of a human.
Harold and Kumar are pre-med and pre-pharmacy students, respectively. They
complain to their biology professor that they should not have to study about plants
because plants have little relevance to their chosen professions.
Which adaptations of land plants are likely to provide Harold with future patients?
I) sporophyte dominance
II) defenses against herbivory
III) adaptations related to wind dispersal of pollen
A) I and II
B) II and III
C) I and III
D) I, II, and III
In the ocean, on either side of the Isthmus of Panama, are thirty species of snapping
shrimp; some are shallow-water species, others are adapted to deep water. There are
fifteen species on the Pacific side and fifteen different species on the Atlantic side. The
Isthmus of Panama started rising about ten million years ago. The oceans were
completely separated by the isthmus about three million years ago.
In the following figure, the isthmus separates the Pacific Ocean on the left (side A)
from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus
is separated into five depth habitats (1-5), with 1 being the shallowest.
Which of these habitats is likely to harbor the most recently diverged species?
A) A5
B) B4
C) A3
D) A1
Which of the following is correctly paired with its structure and function?
A) sclerenchyma supporting cells with thick secondary walls
B) ground meristem protective coat of woody stems and roots
C) guard cells waterproof ring of cells surrounding the central stele in roots
D) periderm parenchyma cells functioning in photosynthesis in leaves
According to bottom-up and top-down control models of community organization,
which of the following expressions would imply that an increase in the size of a
carnivore (C) population would negatively impact its prey (P) population, but not vice
versa?
A) P ← C
B) P → C
C) C ↔ P
D) P ← C → P
The mechanism in which the end product of a metabolic pathway inhibits an earlier step
in the pathway is most precisely described as _____.
A) metabolic inhibition
B) feedback inhibition
C) allosteric inhibition
D) noncooperative inhibition
Which of the following best summarizes the relationship between dehydration reactions
and hydrolysis?
A) Dehydration reactions assemble polymers; hydrolysis reactions break polymers
apart.
B) Dehydration reactions eliminate water from membranes; hydrolysis reactions add
water to membranes.
C) Dehydration reactions and hydrolysis reactions assemble polymers from monomers.
D) Hydrolysis reactions create polymers and dehydration reactions create monomers.
In the ocean, on either side of the Isthmus of Panama, are thirty species of snapping
shrimp; some are shallow-water species, others are adapted to deep water. There are
fifteen species on the Pacific side and fifteen different species on the Atlantic side. The
Isthmus of Panama started rising about ten million years ago. The oceans were
completely separated by the isthmus about three million years ago.
In the following figure, the isthmus separates the Pacific Ocean on the left (side A)
from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus
is separated into five depth habitats (1-5), with 1 being the shallowest.
Why should deepwater shrimp on different sides of the isthmus have diverged from
each other earlier than shallow-water shrimp?
A) They have been geographically isolated from each other for a longer time.
B) Cold temperatures, associated with deep water, have accelerated the mutation rate,
resulting in faster divergence in deepwater shrimp.
C) The rise of the land bridge was accompanied by much volcanic activity. Volcanic ash
contains heavy metals, which are known mutagens. Ash fall caused high levels of heavy
metals in the ocean sediments underlying the deep water, resulting in accelerated
mutation rates and faster divergence in deepwater shrimp.
D) Fresh water entering the ocean from the canal is both less dense and cloudier than
seawater. The cloudy fresh water interferes with the ability of shallow-water shrimp to
locate mating partners, which reduces the frequency of mating, thereby slowing the
introduction of genetic variation.
You are studying a large tropical reptile that has a high and relatively stable body
temperature. How would you determine whether this animal is an endotherm or an
ectotherm?
A) You know from its high and stable body temperature that it must be an endotherm.
B) You know that it is an ectotherm because it is not a bird or mammal.
C) You subject this reptile to various temperatures in the lab and find that its body
temperature and metabolic rate change with the ambient temperature. You conclude that
it is an ectotherm.
D) You note that its environment has a high and stable temperature. Because its body
temperature matches the environmental temperature, you conclude that it is an
ectotherm.
The correct sequence of sensory processing is _____.
A) sensory adaptation → stimulus reception → sensory transduction → sensory
perception
B) stimulus reception → sensory transduction → sensory perception → sensory
adaptation
C) sensory perception → stimulus reception → sensory transduction → sensory
adaptation
D) stimulus reception → sensory perception → sensory adaptation → sensory
transduction
Gene therapy requires _____.
A) knowledge and availability of the normal allele of the defective gene
B) the ability to introduce the normal allele into the patient
C) the ability to express the introduced gene at the correct level, time, and tissue site
within the patient
D) knowledge and availability of the normal allele of the defective gene, an ability to
introduce the normal allele into the patient, and an ability to express the introduced
gene at the correct level, and time, and tissue site within the patient
An organism is discovered that thrives in both the presence and absence of oxygen in
the air. Curiously, the consumption of sugar increases as oxygen is removed from the
organism's environment, even though the organism does not gain much weight. This
organism _____.
A) is a normal eukaryotic organism
B) is photosynthetic
C) is an anaerobic organism
D) is a facultative anaerobe
Fossils of Lystrosaurus, a dicynodont therapsid, are most common in parts of
modern-day South America, South Africa, Madagascar, India, South Australia, and
Antarctica. The animal apparently lived in arid regions, and was mostly herbivorous. It
originated during the mid-Permian period, survived the Permian extinction, and
dwindled by the late Triassic, though there is evidence of a relict population in Australia
during the Cretaceous period. Some dicynodonts had two large tusks, extending down
from their upper jaws. The tusks were not used for food gathering, and in some species
were limited to males. Food was gathered using an otherwise toothless beak. Judging
from the fossil record in sedimentary rocks, these pig-sized organisms were the most
common mammal-like reptiles of the Permian.
Anatomically, Lystrosaurus _____.
A) would have had a lower jaw that consisted of a single pair of bones
B) was a tetrapod
C) had skin without scales, typical of modern amphibians
D) would have had no temporal fenestra in its skull
Excretory organs known as Malpighian tubules are present in _____.
A) flatworms
B) insects
C) jellyfish
D) sea stars
The migratory neural crest cells _____.
A) form most of the central nervous system
B) form the spinal cord in the frog
C) form a variety of neural and non-neural structures
D) form the lining of the lungs and of the digestive tract
