Refer to the following graph of an action potential to answer the question(s) below.
The neuronal membrane is at its resting potential at label _____.
A) A
B) B
C) D
D) E
The necropsy (postmortem analysis) of a freshwater fish that died after being placed
accidentally in saltwater would likely show that _____.
A) loss of water by osmosis from cells in vital organs resulted in cell death and organ
failure
B) high amounts of salt had diffused into the fish’s cells, causing them to swell and lyse
C) the kidneys were not able to keep up with the water removal necessary in this
hyperosmotic environment, creating an irrevocable loss of homeostasis
D) the gills became encrusted with salt, resulting in inadequate gas exchange and a
resulting asphyxiation
An advantage of a complete digestive system over a gastrovascular cavity is that the
complete system _____.
A) excludes the need for extracellular digestion
B) allows for specialized regions with specialized functions
C) allows extensive branching
D) facilitates intracellular digestion
Members of two different species possess a similar-looking structure that they use in a
similar way to perform about the same function. Which of the following would suggest
that the relationship more likely represents homology instead of convergent evolution?
A) The two species live at great distance from each other.
B) The two species share many proteins in common, and the nucleotide sequences that
code for these proteins are almost identical.
C) The structures in adult members of both species are similar in size.
D) Both species are well adapted to their particular environments.
Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim,
but crabs have reduced tails that curl under their shells and are not used in swimming.
This is an example of _____.
A) convergent evolution
B) a homologous structure
C) natural selection
D) a vestigial trait
Which climograph shows the climate for location 2?
A) C
B) D
C) F
D) H
Male frogs give calls that attract female frogs to approach and mate. Researchers
examined mating calls of closely related tree frogs in South America. If reinforcement
is occurring, what would you expect if you compare the calls of the two species in
zones of sympatry versus zones of allopatry?
A) Calls would be about the same in both areas.
B) Calls would be more similar in areas of sympatry.
C) Calls would be more different in areas of sympatry.
Familial hypercholesterolemia is characterized by _____.
A) defective LDL receptors on the cell membranes
B) poor attachment of the cholesterol to the extracellular matrix of cells
C) a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes
D) inhibition of the cholesterol active transport system in red blood cells
A cell has enough available ATP to meet its needs for about 30 seconds. What is likely
to happen when an athlete exhausts his or her ATP supply?
A) He or she has to sit down and rest.
B) Catabolic processes are activated that generate more ATP.
C) ATP is transported into the cell from the circulatory system.
D) Other cells take over, and the muscle cells that have used up their ATP cease to
function.
Applying the principle of parsimony to the trait “ability to fly,” which of the two
phylogenetic trees above is better?
A) Tree 1
B) Tree 2
C) Both trees are equally parsimonious.
D) Since the trees show different evolutionary relationships, you cannot determine
which is more parsimonious.
Elevated carbon dioxide levels have been shown to contribute to the greenhouse effect,
resulting in an increase in mean global temperature. Ecosystems where the largest
warming has already occurred include snow-covered northern coniferous forests,
tundra, and arctic sea ice habitats. Which statement best explains how the elimination of
ice-covered ecosystems affects the rise or fall in global temperature?
A) Melting ice releases dissolved ozone gas, which adds to the greenhouse effect.
B) More reflective surfaces of ice are replaced with darker, more absorptive surfaces,
thereby contributing to the warming trend.
C) Large-scale ice melts actually contribute toward lowering global temperatures by
decreasing salinity of the oceans.
D) Carbon dioxide levels are lowered as a result of greater volume of water to
accommodate greater dissolved gas.
Mitochondria are thought to be the descendants of certain alpha proteobacteria. They
are, however, no longer able to lead independent lives because most genes originally
present on their chromosomes have moved to the nuclear genome. Which phenomenon
accounts for the movement of these genes?
A) plasmolysis
B) conjugation
C) translation
D) horizontal gene transfer
Atria contract _____.
A) just prior to the beginning of diastole
B) during diastole
C) immediately after systole
D) during systole
The heartworms that can accumulate within the hearts of dogs and other mammals have
a pseudocoelom, an alimentary canal, and an outer covering that is occasionally shed.
To which phylum does the heartworm belong?
A) Platyhelminthes
B) Arthropoda
C) Nematoda
D) Annelida
You are most likely to observe coprophagy in _____.
A) carnivores
B) herbivores
C) fluid feeders
D) suspension feeders
In a meristematic region, the cell plate during mitosis is perpendicular to the side of the
stem. In what direction will the stem grow?
A) laterally in width
B) vertically in height
C) at a 45-degree angle from the ground
D) away from the sun
Which structure is NOT part of the endomembrane system?
A) nuclear envelope
B) chloroplast
C) Golgi apparatus
D) plasma membrane
Absorbance at Various pH Levels
The accompanying table represents the results of an experiment where the effects of pH
buffers on an enzyme found in saliva (amylase) were studied. A spectrophotometer set
at 500nm was used to measure absorbance at the various pH levels every 20 sec for 2
min. The higher absorbance values would indicate greater enzyme activity. All
experiments were conducted at the same temperature.
Which statement correctly identifies the result that the optimum pH for amylase
function is 7?
A) The pH with the lowest absorbance values would indicate the optimum pH for
amylase since this pH does not affect the structure or function of the protein.
B) The pH with the highest absorbance values would indicate the optimum pH for
amylase since this pH does not affect the structure or function of the protein.
C) At pH 9, the enzyme is denatured and will lose its function, but not its structure.
D) At pH 4, the structure of the enzyme will be altered, and the enzyme would not be
able to catalyze the reaction.
Food and water appetites are under the regulatory influence of the _____.
A) cerebrum
B) thalamus
C) hypothalamus
D) medulla oblongata
Preparation for the fight-or-flight response includes activation of the _____ nervous
system
A) sympathetic
B) somatic
C) central
D) parasympathetic
If you experimentally increase the concentration of Na+ outside a cell while
maintaining other ion concentrations as they were, what would happen to the cell’s
membrane potential?
A) The membrane potential would decrease.
B) The membrane potential would increase.
C) The membrane potential would be unaffected.
D) The answer depends on the thermodynamic potential.
In eukaryotes, genetic information is passed to the next generation by processes that
include mitosis or meiosis. Which of the explanations identifies the correct process and
supports the claim that heritable information is passed from one generation to another?
A) During mitosis, DNA replication occurs twice within the cell cycle to insure a full
set of chromosomes within each of the daughter cells produced.
B) Mitosis, followed by cytokinesis, produces daughter cells that are genetically
different from the parent cell, thus insuring variation within the population.
C) In asexual reproduction, a single individual is the sole parent and passes copies of its
genes to its offspring without the fusion of gametes.
D) Single-celled organisms can fuse their cells, reproducing asexually through mitosis
to form new cells that are not identical to the parent cell.
Marfan syndrome in humans is caused by an abnormality of the connective tissue
protein fibrillin. Patients are usually very tall and thin, with long spindly fingers,
curvature of the spine, sometimes weakened arterial walls, and sometimes ocular
problems, such as lens dislocation. Which of the following would you conclude about
Marfan syndrome from this information?
A) It is recessive.
B) It is dominant.
C) It is pleiotropic.
D) It is epistatic.
The main reason polar regions are cooler than the equator is that _____.
A) sunlight strikes the poles at a lower angle
B) the poles are farther from the sun
C) the polar atmosphere is thinner and contains fewer greenhouse gases
D) the poles are permanently tilted away from the sun
When antibodies bind antigens, the clumping of antigens results from _____.
A) the antibody having at least two binding regions
B) disulfide bridges between the antigens
C) bonds between class I and class II MHC molecules
D) denaturation of the antibodies
The hormone that stimulates the production of red blood cells, and the organ where this
hormone is synthesized, are _____.
A) growth hormone and pancreas, respectively
B) erythropoietin and kidney, respectively
C) cortisol and adrenal gland, respectively
D) acetylcholine and bone marrow, respectively
Translation requires _____.
A) mRNA, tRNA, DNA, and rRNA
B) mRNA, DNA, and rRNA
C) mRNA, tRNA, and rRNA
D) mRNA, tRNA, and DNA
Which of the following graphs best illustrates the growth curve of a small population of
rodents that has increased to a static carrying capacity?
A)
B)
C)
D)
Which of these statements accurately describes a similarity between sharks and
ray-finned fishes?
A) They are equally able to exchange gases with the environment while stationary.
B) They are highly maneuverable due to their flexibility.
C) They have a lateral line that is sensitive to vibrations.
D) A swim bladder helps control buoyancy.
Which habitat type in the figure above makes available the most new tissue to
consumers?
A) tropical wet forest
B) open ocean
C) algal beds and reefs
D) wetlands
Which of the following can occur by the process of meiosis but not mitosis?
A) Haploid cells fuse to form diploid cells.
B) Haploid cells multiply into more haploid cells.
C) Diploid cells form haploid cells.
D) A diploid cell combines with a haploid cell.
Suppose you laid a seedling on its side so that the root was parallel to the ground as
shown in the figure above. Several hours after the change in position, where in the root
cells (position A, B, or C in the figure above) would you find the amyloplasts?
A) A
B) B
C) C
In which of the following would there be the greatest need for osmoregulation?
A) an animal connective tissue cell bathed in isotonic body fluid
B) a salmon moving from a river into an ocean
C) a red blood cell surrounded by plasma
D) a plant being grown hydroponically in a watery mixture of designated nutrients
Which of the following is most critical for the association between histones and DNA?
A) Histones are small proteins.
B) Histones are highly conserved (that is, histones are very similar in every eukaryote).
C) There are at least five different histone proteins in every eukaryote.
D) Histones are positively charged.