CAP is said to be responsible for positive regulation of the lac operon because _____.
A) CAP binds cAMP
B) CAP binds to the CAP-binding site
C) CAP prevents binding of the repressor to the operator
D) CAP bound to the CAP-binding site increases the frequency of transcription
initiation
The synthesis of ATP by oxidative phosphorylation, using the energy released by
movement of protons across the membrane down their electrochemical gradient, is an
example of _____.
A) active transport
B) an endergonic reaction coupled to an exergonic reaction
C) a reaction with a positive ΔG
D) allosteric regulation
Singer and Nicolson’s fluid mosaic model of the membrane proposed that
membranes_____.
A) are a phospholipid bilayer between two layers of hydrophilic proteins
B) are a single layer of phospholipids and proteins
C) consist of protein molecules embedded in a fluid bilayer of phospholipids
D) consist of a mosaic of polysaccharides and proteins
A biology student hiking in a forest happens upon an erect, 15-cm-tall plant that bears
microphylls and a strobilus at its tallest point. When disturbed, the cone emits a dense
cloud of brownish dust. A pocket magnifying glass reveals the dust to be composed of
tiny spheres with a high oil content.
This student has probably found a(n) _____.
A) bryophyte sporophyte
B) fern sporophyte
C) horsetail gametophyte
D) lycophyte sporophyte
What is malonic acid’s role with respect to succinate dehydrogenase? Malonic acid
_____.
A) is a competitive inhibitor
B) blocks the binding of fumarate
C) is a noncompetitive inhibitor
D) is an allosteric regulator
The circulatory systems of bony fishes, rays, and sharks are most similar to _____.
A) those of birds, with a four-chambered heart
B) the portal systems of mammals, where two capillary beds occur sequentially, without
passage of blood through a pumping chamber
C) those of sponges, where gas exchange in all cells occurs directly with the external
environment
D) those of humans, where there are four pumping chambers to drive blood flow
When 10,000 molecules of ATP are hydrolyzed to ADP and i in a test tube, about half
as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of
the following is the best explanation for this observation?
A) Cells are open systems, but a test tube is an isolated system.
B) Cells are less efficient at heat production than nonliving systems.
C) The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube
does not need enzymes.
D) Reactant and product concentrations in the test tube are different from those in the
cell.
A phylogenetic tree constructed using sequence differences in mitochondrial DNA
would be most valid for discerning the evolutionary relatedness of _____.
A) archaeans and bacteria
B) fungi and animals
C) chimpanzees and humans
D) sharks and dolphins
Fossil fungi date back to the origin and early evolution of plants. What combination of
environmental and morphological change is similar in the evolution of both fungi and
plants?
A) presence of “coal forests” and change in mode of nutrition
B) periods of drought and presence of filamentous body shape
C) predominance in swamps and presence of cellulose in cell walls
D) colonization of land and loss of flagellated cells
You observe a species of bird that, upon hatching, has contact with its parents only
while being fed. You also never hear the parents sing during the feeding process. What
would you propose about song learning in this species of bird?
A) Song learning in this species is most likely learned.
B) The period of imprinting is likely later in the bird’s life.
C) The males will learn song when they congregate with other males of their species
during the winter.
D) Song learning in this species is most likely innate.
Which of the following best substantiates why location 3 is an equatorial (tropical)
climate?
A) It has a monsoon season during the winter months.
B) The temperature is high for each monthly average.
C) The temperatures reach 100F during some months.
D) The temperatures are lower in June, July, and August.
How many neutrons are present in the nucleus of a phosphorus-32 (32P) atom (see the
figure above)?
A) 15
B) 16
C) 17
D) 32
The most plausible hypothesis to explain why species richness is higher in tropical than
in temperate regions is that _____.
A) tropical communities are younger
B) tropical regions generally have more available water and higher levels of solar
radiation
C) higher temperatures cause more rapid speciation
D) tropical regions have very high rates of immigration and very low rates of extinction
Codons are part of the molecular structure of _____.
A) a protein
B) mRNA
C) tRNA
D) rRNA
A snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of _____.
A) diatoms
B) foraminiferans
C) ciliates
D) water molds
A stroke volume of 70 mL/cycle in a heart with a pulse of 72 cycles per minute results
in a cardiac output of about _____.
A) 5 liters per minute
B) 50 milliliters per minute
C) 0.5 liters per minute
D) 50 liters per minute
Pair-bonding in a population of prairie voles can be prevented by _____.
A) the ensuing confusion caused by introducing meadow voles
B) administering a drug that inhibits the brain receptor for vasopressin in the central
nervous system (CNS) of males
C) dying the coat color from brown to blond in either male or female prairie voles
D) allowing the population size to reach critically low levels
A gardener is concerned that her greenhouse is getting too hot from too much light and
seeks to shade her plants with colored translucent plastic sheets, the color of which
allows passage of only that wavelength. What color should she use to reduce overall
light energy but still maximize plant growth?
A) green
B) blue
C) orange
D) Any color will work equally well.
All female mammals have one active X chromosome per cell instead of two. What
causes this?
A) activation of the XIST gene on the X chromosome that will become the Barr body
B) activation of the BARR gene on one X chromosome, which then becomes inactive
C) inactivation of the XIST gene on the X chromosome derived from the male parent
D) attachment of methyl (CH3) groups to the X chromosome that will remain active
Melatonin is secreted by the_____.
A) hypothalamus during the day
B) pineal gland during the night
C) autonomic nervous system during the winter
D) posterior pituitary gland during the day
A patient who has a high level of mast cell activity, dilation of blood vessels, and acute
drop in blood pressure is likely suffering from _____.
A) an autoimmune disease
B) a typical skin allergy (contact dermatitis) that can be treated by antihistamines
C) an organ transplant, such as a skin graft
D) anaphylactic shock immediately following exposure to an allergen
The difference between geographic isolation and habitat differentiation (isolation) is the
_____.
A) relative locations of two populations as speciation occurs
B) speed (tempo) at which two populations undergo speciation
C) amount of genetic variation that occurs among two gene pools as speciation occurs
D) identity of the phylogenetic kingdom or domain in which these phenomena occur
According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to
keep the engulfed cell alive, rather than digesting it as food?
A) The engulfed cell provided the host cell with adenosine triphosphate (ATP).
B) The engulfed cell provided the host cell with carbon dioxide.
C) The engulfed cell allowed the host cell to metabolize glucose.
D) The host cell was able to survive anaerobic conditions with the engulfed cell alive.
Codons are three-base sequences that specify the addition of a single amino acid. How
do eukaryotic codons and prokaryotic codons compare?
A) Prokaryotic codons usually contain different bases than those of eukaryotes.
B) Prokaryotic codons usually specify different amino acids than those of eukaryotes.
C) The translation of codons is mediated by tRNAs in eukaryotes, but translation
requires no intermediate molecules such as tRNAs in prokaryotes.
D) Codons are a nearly universal language among all organisms.
Antidiuretic hormone (ADH) and the renin-angiotensin-aldosterone system (the RAAS)
work together in maintaining osmoregulatory homeostasis through which of the
following ways?
A) ADH regulates the osmolarity of the blood by altering renal reabsorption of water,
and the RAAS maintains the osmolarity of the blood by stimulating Na+ and water
reabsorption.
B) ADH and the RAAS work antagonistically; ADH stimulates water reabsorption
during dehydration and the RAAS causes increased excretion of water when it is in
excess in body fluids.
C) Both stimulate the adrenal gland to secrete aldosterone, which increases both blood
volume and pressure via its receptors in the urinary bladder.
D) ADH and the RAAS combine at the receptor sites of proximal tubule cells, where
reabsorption of essential nutrients takes place.
The diagnosis of hypertension in adults is based on the _____.
A) measurement of fatty deposits on the endothelium of arteries
B) measurement of the LDL/HDL ratio in peripheral blood
C) percentage of blood volume made up of platelets
D) blood pressure being greater than 140 mm Hg systolic and/or greater than 90 mm Hg
diastolic
Starch and cellulose _____.
A) are polymers of glucose
B) are cis-trans isomers of each other
C) are used for energy storage in plants
D) are structural components of the plant cell wall
Which of the following was derived from an ancestral cyanobacterium?
A) chloroplast
B) mitochondrion
C) flagella
D) mitosome
Why are changes in the global carbon cycle important?
I) Burning reduces available carbon for primary producers and, therefore, primary
consumers.
II) Deforestation and suburbanization reduce an area’s net primary productivity.
III) Increasing atmospheric concentrations of carbon dioxide could alter Earth’s climate.
IV) By using fossil fuels we are destroying a nonrenewable resource.
A) only I and III
B) only II and IV
C) only II, III, and IV
D) only I, II, III, and IV
Plants often use changes in day length (photoperiod) to trigger events such as dormancy
and flowering. It is logical that plants have evolved this mechanism because
photoperiod changes_____.
A) are more predictable than air temperature changes
B) predict moisture availability
C) are modified by soil temperature changes
D) can reset the biological clock
In the process of transcription, _____.
A) DNA is replicated
B) RNA is synthesized
C) proteins are synthesized
D) mRNA attaches to ribosomes
Which of the following is a producer?
A) kinetoplastid
B) apicomplexan
C) diatom
D) ciliates
Carbon dioxide (CO2) is released during which of the following stages of cellular
respiration?
A) glycolysis and the oxidation of pyruvate to acetyl CoA
B) oxidation of pyruvate to acetyl CoA and the citric acid cycle
C) oxidative phosphorylation and fermentation
D) fermentation and glycolysis