A plant’s first line of defense against infection is
A) Avr genes.
B) its epidermis.
C) R genes.
D) salicylic acid.
Which of the following processes underlies the thigmotropic behavior of a green bean
tendril?
A) rotation of the tendril in response to photoperiod
B) rotation of the tendril in response to a biological clock
C) extra proliferation of cells on the shaded side of the tendril
D) slower growth on the side where an object is touching the tendril
The maximum number of individuals a habitat can support is called its
A) reproductive potential.
B) carrying capacity.
C) community size.
D) density-dependent factor.
In yeast cells,
A) lactic acid is produced during anaerobic respiration.
B) lactic acid is produced during glycolysis.
C) alcohol is produced during the citric acid cycle.
D) alcohol is produced after glycolysis.
Atrazine is a widely used herbicide that binds to a protein in photosystem II, ultimately
causing a breakdown in electron transport. Atrazine would first inhibit the production of
A) NADPH.
B) G3P.
C) ATP.
D) O2.
Which of the following contributes to gas exchange in the human fetus?
A) the lower blood pH of the embryo
B) the lack of turbulence in fetal blood
C) the high oxygen levels maintained in the amniotic fluid by the placenta
D) the stronger attraction that fetal hemoglobin has for oxygen when compared to adult
hemoglobin
How can the success of one group of organisms promote the adaptive radiation of a
second group?
A) by providing new food resources, habitats, etc. for the second group
B) by competing with the second group, promoting its adaptive radiation
C) by preying on the second group, which hastens its adaptation
D) by filling most of the available niches, which forces the second group to evolve
greater diversity
What was the probable role of oxygen gas in the early stages of life’s appearance on
Earth?
A) Cellular respiration, which depends on oxygen availability, provided abundant
energy to the first life-forms.
B) Oxygen promoted the formation of complex organic molecules through physical
processes.
C) Oxygen gas tends to disrupt organic molecules, so its absence promoted the
formation and stability of complex organic molecules on the early Earth.
D) Abundant atmospheric oxygen would have created an ozone layer, which blocked
out ultraviolet light and thereby protected the earliest life-forms.
Which of the following is another term used for atomic mass?
A) darwin
B) mendel
C) dalton
D) calvin
Unlike animal cells, plant cells have ________ and ________. Unlike plant cells,
animal cells have ________.
A) chloroplasts; cell walls; centrioles
B) centrioles; chloroplasts; cell walls
C) chloroplasts; cell walls; a nucleus
D) centrioles; cell walls; large central vacuoles
Which of the following is an example of a population?
A) all of the microorganisms on your skin
B) all of the students in your classroom
C) all students attending colleges and universities in your state
D) the various plants found in prairies in the western United States
The trickling filter at a sewage treatment plant works by
A) passing wastewater through fine sand, mechanically removing fine pollution
particles.
B) passing wastewater through a thick bed of rocks that contain chemicals that sterilize
the water and neutralize chemical pollutants or bind with them to produce a harmless
precipitate.
C) passing wastewater through a thick bed of rocks. Biofilms of bacteria and fungi on
the rocks remove much of the organic material dissolved in the wastewater.
D) adding fertilizer to wastewater and passing it through a culture medium rich in
oil-eating prokaryotes.
One assumption about plant reproduction is that because it requires so many resources
(energy and molecules), reproductive output is resource-limited. Which of the following
statements provides evidence that this assumption may be incorrect?
A) There is a correlation between the amount of sunlight a plant receives and how much
fruit it produces.
B) Hand-pollinated plants produce more seeds than naturally pollinated plants.
C) Plants growing in moist conditions produce more flowers than plants growing in dry
conditions.
D) Domesticated plants produce more seeds than wild plants.
Which of the following cell types is responsible for the humoral immune response?
A) B cells
B) neutrophils
C) natural killer cells
D) macrophages
Over the past 500 million years, there have been ________ mass extinctions, and each
time, at least ________ of the species on Earth became extinct.
A) two; 25%
B) five; 25%
C) five; 50%
D) twelve; 96%
To protect U.S. soldiers serving overseas, each soldier receives vaccinations against
several diseases, including smallpox, before deployment. Following intelligence about
an imminent smallpox threat in Iraq, the U.S. Army wants to ensure that soldiers
stationed there are fully protected from exposure to the disease, so all the soldiers in the
threat zone are given a second vaccination against smallpox.
The first vaccination provides immunity because
A) a localized inflammatory response is initiated.
B) the vaccine contains manufactured antibodies against smallpox.
C) antigenic determinants in the vaccine activate B cells, which form plasma cells as
well as memory cells.
D) the vaccine contains antibiotics and other drugs that kill the smallpox virus.
As global temperatures continue to rise, what is a likely outcome?
A) loss of populations of fish
B) greater overharvesting of medicinal plant species
C) less greenhouse gas emissions
D) formation of new glaciers
Which of the following is a normal process of photosynthesis that could not occur if all
reaction centers were inactivated by a toxin?
A) donation of excited electrons by chlorophyll a to a primary electron acceptor
B) donation of excited electrons by chlorophyllb to a primary electron acceptor
C) absorption of photons by chlorophyll b
D) absorption of photons by carotenoids
The fossil “hobbits” discovered in Indonesia may be ________ that lived ________.
A) a newly discovered species of Homo; as recently as 18,000 years ago
B) a population of Homo sapiens with a genetic disorder; at the same time as the
Neanderthals
C) a lineage of early hominins; about 5 million years ago
D) a dwarf lineage of Australopithecus; around the same time as “Lucy”
During a discussion about ecosystems, a student says, “Plants eat sunlight, and animals
eat other organisms.” Which of the following responses to the student’s comment is
most accurate?
A) Plants don’t eat sunlight; they eat sugars that they get from the soil.
B) Plants don’t eat sunlight; they use it to make sugars.
C) Plants eat sunlight, but they also eat other organism such as decomposers.
D) Plants eat sunlight, but animals also eat bacteria, which are not considered
organisms.
Which of the following is a nonsteroid hormone?
A) glucagon
B) a glucocorticoid
C) estrogen
D) androgen
The structure of the esophagus fits its function in that
A) it can direct food to the lungs or stomach.
B) it has smooth muscle for peristalsis.
C) it is regulated by contractions in the pharynx.
D) its length determines the volume of food an animal can ingest.
Which of the following statements regarding the movement of electrons during cellular
respiration is true?
A) Electrons tend to move away from O2.
B) O2 is eventually oxidized by the electrons to form water.
C) The electrons release large amounts of energy each time they are transferred from
one molecule to another.
D) O2 is reduced when it accepts electrons and forms water.
Mad cow disease serves as an example of how interdependent ________ and ________
are to protein.
A) solubility; texture
B) form; construction
C) structure; function
D) adaptability; development
Which of the following causes food poisoning and typhoid fever?
A) Escherichia coli
B) Bacillus anthracis
C) Clostridium botulinum
D) Salmonella
Which of the following statements about herpesviruses is false?
A) Herpesviruses reproduce inside the host cell’s mitochondria.
B) Herpesviruses acquire their envelopes from the host cell nuclear membrane.
C) Herpesviruses may remain dormant for long periods of time while inside the host
cell nucleus.
D) Herpesviruses may cause cold sores or genital sores to appear during times of
physical or emotional stress.
The way that genetic material of a bacteriophage enters a bacterium is most like the
way that
A) a drug is injected with a hypodermic needle.
B) a person swallows a pill.
C) skin lotion is rubbed onto the hands.
D) water soaks into a sponge.
Complete the analogy: ________ is/are to birds as ________ is/are to mammals.
A) Wings; legs
B) Water; milk
C) Feathers; hair
D) Wings; opposable thumbs
Speciation, or the formation of new species, is
A) a form of microevolution.
B) responsible for the diversity of life.
C) necessary for natural selection and adaptation.
D) an event that has occurred only a few times in the history of the planet.
About 80% of plants have mycorrhizae linking them to
A) chytrids.
B) glomeromycetes.
C) ascomycetes.
D) basidiomycetes.
Which of the following permits a single gene to code for more than one polypeptide?
A) retention of different introns in the final version of the different mRNA strands
B) alternative RNA splicing
C) genetic differentiation
D) addition of different types of caps and tails to the final version of the mRNA strands
Skin cells are fastened into strong sheets by
A) basal bodies.
B) anchoring junctions.
C) tight junctions.
D) communicating junctions.
What type of immune response is always disadvantageous to a person?
A) inflammatory
B) humoral
C) autoimmune
D) complement-mediated
Which of the following will likely decrease a population’s size?
A) improving the quality of its habitat
B) increasing the size of its habitat
C) practicing sustainable resource management in its habitat
D) decreasing the food supply available to the population