Bonds between two atoms that are equally electronegative are _____.
A) hydrogen bonds
B) polar covalent bonds
C) nonpolar covalent bonds
D) ionic bonds
Independent assortment of chromosomes occurs during _____.
A) meiosis I only
B) meiosis II only
C) mitosis and meiosis I
D) mitosis and meiosis II
Which of the following human diseases is caused by a virus that requires reverse
transcriptase to transcribe its genome inside the host cell?
A) herpes
B) AIDS
C) smallpox
D) influenza
You have isolated DNA from three different cell types of the same organism,
determined the relative DNA content for each type, and plotted the results on the graph
shown in the figure below. Refer to the graph to answer the following question(s).
Which sample might represent a zygote?
A) I
B) II
C) III
D) either I or II
Which of the following develops the greatest pressure on the blood in the mammalian
aorta?
A) systole of the left atrium
B) diastole of the right ventricle
C) systole of the left ventricle
D) diastole of the right atrium
Once heat is transferred to the soil, where does it go next (reference the study by
Noormets et al. 2004)?
I) The heat is emitted back to the atmosphere.
II) The heat is transferred to other soil layers.
III) The heat is stored in the soil.
A) only I
B) only II
C) only III
D) I, II, and III
The various taxonomic levels (for example, phyla, genera, classes) of the hierarchical
classification system differ from each other on the basis of _____.
A) how widely the organisms assigned to each are distributed throughout the
environment
B) their inclusiveness
C) the relative genome sizes of the organisms assigned to each
D) morphological characters that are applicable to all organisms
Increasing the substrate concentration in an enzymatic reaction could overcome which
of the following?
A) the need for a coenzyme
B) allosteric inhibition
C) competitive inhibition
D) insufficient cofactors
A hypothetical bacterium swims among human intestinal contents until it finds a
suitable location on the intestinal lining. It adheres to the intestinal lining using a
feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal
matter from a human in whose intestine this bacterium lives can spread the bacterium,
even after being mixed with water and boiled. The bacterium is not susceptible to the
penicillin family of antibiotics. It contains no plasmids and relatively little
peptidoglycan.
This bacterium derives nutrition by digesting human intestinal contents. Thus, this
bacterium is an _____.
A) aerobic chemoheterotroph
B) aerobic chemoautotroph
C) anaerobic chemoheterotroph
D) anaerobic chemoautotroph
The figure above shows a simple metabolic pathway. According to Beadle and Tatum’s
hypothesis, how many genes are necessary for this pathway?
A) 1
B) 2
C) 3
D) It cannot be determined from the pathway.
When the Bicoid protein is expressed in Drosophila, the embryo is still syncytial
(divisions between cells are not yet fully developed). This information helps to explain
which observation by Nsslein-Volhard and Wieschaus?
A) mRNA from the egg is translated into the Bicoid protein.
B) Bicoid protein diffuses throughout the embryo in a concentration gradient.
C) Bicoid protein serves as a transcription regulator.
D) Bicoid protein determines the dorsoventral axis of the embryo.
Stimuli alter the activity of excitable sensory cells and generate action potentials via
_____.
A) integration
B) transmission
C) transduction
D) amplification
The cortical reaction of sea urchin eggs functions directly in _____.
A) the formation of a fertilization envelope
B) the production of a fast block to polyspermy
C) the release of hydrolytic enzymes from the sperm
D) the generation of an electrical impulse by the egg
Which of the following would inhibit the growth of most plants?
A) abundant humus
B) air spaces
C) good drainage
D) a pH above 10.0
Which of the following would be LEAST likely to affect osmosis in plants?
A) a difference in solute concentrations
B) receptor proteins in the membrane
C) aquaporins
D) a difference in water potential
Rate of an enzyme-catalyzed reaction as a function of varying reactant concentration,
with the concentration of enzyme constant.
In the figure, why does the reaction rate plateau at higher reactant concentrations?
A) Feedback inhibition by product occurs at high reactant concentrations.
B) Most enzyme molecules are occupied by substrate at high reactant concentrations.
C) The reaction nears equilibrium at high reactant concentrations.
D) The rate of the reverse reaction increases with reactant concentration.
Protein kinases are enzymes that transfer the terminal phosphate from ATP to an amino
acid residue on the target protein. Many are located on the plasma membrane as integral
membrane proteins or peripheral membrane proteins. What purpose may be served by
their plasma membrane localization?
A) ATP is more abundant near the plasma membrane.
B) They can more readily encounter and phosphorylate other membrane proteins.
C) Membrane localization lowers the activation energy of the phosphorylation reaction.
D) They flip back and forth across the membrane to access target proteins on either
side.
Which of the following statements is true concerning the accompanying figure?
A) It represents a C4 photosynthetic system.
B) It represents an adaptation that maximizes photorespiration.
C) It represents a C3 photosynthetic system.
D) It represents a CAM photosynthetic system.
The proximate causes of behavior are interactions with the environment, but behavior is
ultimately shaped by _____.
A) hormones
B) evolution
C) pheromones
D) the nervous system
Many species of snakes lay eggs. However, in the forests of northern Minnesota, where
growing seasons are short, only live-bearing snake species are present. This trend
toward species that have live birth in a particular environment is an example of _____.
A) an exaptation
B) sexual selection
C) species selection
D) goal direction in evolution
Based on the data in the Amino Acid Identity Table, which two members of the human
globin gene family are the most divergent?
A) a1 and ß
B) ? and ß
C) a1 and a2
D) a1 and G?
In the process of science, which of these is tested?
A) a result
B) an observation
C) a hypothesis
D) a control group
A person is most likely to recover from a viral infection if the infected cells _____.
A) can undergo normal cell division
B) can carry on translation, at least for a few hours
C) produce and release viral protein
D) transcribe viral mRNA
Sex determination in mammals is due to the SRY gene. Which of the following could
allow a person with an XX karyotype to develop a male phenotype?
A) the loss of the SRY gene from an autosome
B) translocation of SRY to a X chromosome
C) a person with an extra autosomal chromosome
D) a person with one normal and one shortened (deleted) X
Asexual reproduction in yeasts occurs by budding. Due to unequal cytokinesis, the
“bud” cell receives less cytoplasm than the parent cell. Which of the following should
be true of the smaller cell until it reaches the size of the larger cell?
A) It should produce fewer fermentation products per unit time.
B) It should be transcriptionally less active.
C) It should have reduced motility.
D) It should have a smaller nucleus.
Two populations of birds with somewhat different coloration live on opposite sides of a
peninsula. The habitat between the populations is not suitable for these birds. When
birds from the two populations are brought together, they produce young whose
appearance is intermediate between the two parents. These offspring will breed with
each other or with birds from either parent population, and all offspring of these
pairings appear intermediate to various degrees.
The two populations are _____.
A) different subspecies, under the morphological species concept
B) different species, under the biological species concept
C) different species, under the phylogenetic species concept
Which of the following is a true statement about plant reproduction?
A) Embryophytes are small plants in an early developmental stage.
B) Male and female bryophytes each produce a type of gametangia.
C) Eggs and sperm of most land plants swim toward one another.
D) Bryophytes are limited to asexual reproduction.
Several scientific laboratories across the globe are involved in research concerning the
origin of life on Earth. Which of these questions is currently the most problematic and
would have the greatest impact on our understanding if we were able to answer it?
A) How can amino acids, simple sugars, and nucleotides be synthesized abiotically?
B) How did RNA sequences come to carry the code for amino acid sequences?
C) How could polymers involving lipids and/or proteins form membranes in aqueous
environments?
D) How can RNA molecules act as templates for the synthesis of complementary RNA
molecules?
When an ionic compound such as sodium chloride (NaCl) is placed in water, the
component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and
chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g.,
glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution.
Which of the following solutions would be expected to contain the greatest number of
solute particles (molecules or ions)?
A) 1 liter of 0.5M NaCl
B) 1 liter of 1.0M NaCl
C) 1 liter of 1.0M glucose
D) 1 liter of 1.0 M NaCl and 1 liter of 1.0 M glucose will contain equal numbers of
solute particles.
In mitochondria, chemiosmosis moves protons from the matrix into the intermembrane
space, whereas in chloroplasts, chemiosmosis moves protons from the _____.
A) matrix to the stroma
B) stroma to the thylakoid space
C) intermembrane space to the matrix
D) thylakoid space to the stroma
Due to its system of air sacs connected to the lungs, the respiratory system of birds is
arguably the most effective respiratory system of all air-breathers. Upon inhalation, air
first flows into posterior air sacs, then into the lungs, and then into anterior air sacs on
the way to being exhaled. Thus, there is one-way flow of air through the lungs, along
thousands of tubules called parabronchi.
If the inner lining of the air sacs is neither thin nor highly vascularized, then what can
be inferred about the air sacs?
A) They must not belong to the respiratory system.
B) They cannot be derived from endoderm.
C) They are not efficient sites of gas exchange between air and blood.
D) They cannot effectively moisturize the air before it reaches the lungs.
Many flowering plants coevolve with specific pollinators. The Madagascar orchid has a
12-inch floral tube and is a reliable nectar source for the hawkmoth, which has a
correspondingly long proboscis (tongue). Which statement most accurately describes
how coevolution might have occurred for the hawkmoth and Madagascar orchid shown
here?
A) The hawkmoths that expended the most effort to reach the nectar would be the most
fit, and pass the longer tongue phenotype to their offspring.
B) Natural selection would favor orchids with nectar tubes just long enough to for an
insect with pollen to make contact. Hawkmoths whose tongue could reach the deep
tubes would be more fit.
C) Hawkmoths whose tongue was just long enough to obtain nectar, but not able to pick
up pollen would become the most fit in the population.
D) It is most likely that mutations that resulted in both the length of the orchid floral
tube and the length of the hawkmoth tongue occurred abruptly and simultaneously.
If pigments from a particular species of plant are extracted and subjected to paper
chromatography, which of the following is most likely?
A) Paper chromatography for the plant would isolate a single band of pigment that is
characteristic of that particular plant.
B) Paper chromatography would separate the pigments from a particular plant into
several bands.
C) The isolated pigments would be some shade of green.
D) Paper chromatography would isolate only the pigments that reflect green light.