What is thought to be the correct sequence of these events, from earliest to most recent,
in the evolution of life on Earth?
1. origin of mitochondria
2. origin of multicellular eukaryotes
3. origin of chloroplasts
4. origin of cyanobacteria
5. origin of fungal-plant symbioses
A) 4, 3, 2, 1, 5
B) 4, 1, 2, 3, 5
C) 4, 1, 3, 2, 5
D) 4, 3, 1, 5, 2
Most of the water taken up by a plant is_____.
A) used as a solvent
B) used as a hydrogen source in photosynthesis
C) lost during transpiration
D) used to keep cells turgid
The symbols +, -, and o are to be used to show the results of interactions between
individuals and groups of individuals in the examples that follow. The symbol + denotes
a positive interaction, – denotes a negative interaction, and o denotes where individuals
are not affected by interacting. The first symbol refers to the first organism mentioned.
What interactions exist between a tick on a dog and the dog?
A) +/o
B) +/-
C) o/o
D) -/-
In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for
oxygen than that of adults. This is due to _____.
A) nonidentical genes that produce different versions of globins during development.
B) pseudogenes, which interfere with gene expression in adults.
C) the attachment of methyl groups to cytosine following birth, which changes the type
of hemoglobin produced.
D) histone proteins changing shape during embryonic development.
Over long periods of time, many cave-dwelling organisms have lost their eyes.
Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How
can natural selection account for these losses?
A) Natural selection cannot account for losses, but accounts only for new structures and
functions.
B) Natural selection accounts for these losses by the principle of use and disuse.
C) Under particular circumstances that persisted for long periods, each of these
structures presented greater costs than benefits.
D) The ancestors of these organisms experienced harmful mutations that forced them to
lose these structures.
Currently, two of the living elephant species (X and Y) are placed in the genus
Loxodonta and a third surviving species (Z) is placed in the genus Elephas. Assuming
this classification reflects evolutionary relatedness, which of the following is the most
accurate phylogenetic tree?
A)
B)
C)
D)
Which of the following is the best description of a control for an experiment?
A) The control group is kept in an unchanging environment.
B) The control group is matched with the experimental group except for one
experimental variable.
C) The control group is exposed to only one variable rather than several.
D) Only the experimental group is tested or measured.
Matter is gained or lost in ecosystems. How does this occur?
A) Chemoautotrophic organisms can convert matter to energy.
B) Matter can be moved from one ecosystem to another.
C) Photosynthetic organisms convert solar energy to sugars.
D) Heterotrophs convert heat to energy.
If a DNA sample were composed of 10% thymine, what would be the percentage of
guanine?
A) 10
B) 40
C) 80
D) It is impossible to tell from the information given.
During a year, plants never use 100% of the incoming solar radiation for
photosynthesis. What is a reasonable explanation for this?
I) Plants cannot photosynthesize as well during winter (in cold winter climates).
II) Plants cannot photosynthesize as well on cloudy days.
III) The pigments that drive photosynthesis respond to only a fraction of the
wavelengths that are available.
A) only I
B) only II
C) only III
D) I, II, and III
Which of these is a karyotype?
A) a display of all of the cell types in an organism
B) organized images of a cell’s chromosomes
C) the appearance of an organism
D) a display of a cell’s mitotic stages
Elephants are not the most dominant species in African grasslands, yet they influence
community structure. The grasslands contain scattered woody plants, but they are kept
in check by the uprooting activities of the elephants. Take away the elephants, and the
grasslands convert to forests or to shrublands. The newly growing forests support fewer
species than the previous grasslands. Which of the following describes why elephants
are the keystone species in this scenario?
A) Elephants exhibit a disproportionate influence on the structure of the community
relative to their abundance.
B) Grazing animals depend upon the elephants to convert forests to grassland.
C) Elephants are the biggest herbivore in this community.
D) Elephants help other populations survive by keeping out many of the large African
predators.
How does a scientific theory differ from a scientific hypothesis?
A) Theories are proposed to test scientific hypotheses.
B) Theories are usually an explanation for a more general phenomenon; hypotheses
typically address more specific issues.
C) Hypotheses are usually an explanation for a more general phenomenon; theories
typically address more specific issues.
D) Confirmed theories become scientific laws; hypotheses become theories.
In its mechanism, photophosphorylation is most similar to _____.
A) substrate-level phosphorylation in glycolysis
B) oxidative phosphorylation in cellular respiration
C) the Calvin cycle
D) reduction of NADP+
You are looking through a microscope at a slide of animal tissue and see a single layer
of flat, closely packed cells that cover a surface. This specific tissue is most likely
_____.
A) adipose
B) a tendon
C) epithelial
D) a neuron
The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that
_____.
A) urea can be exchanged for Na+
B) urea is less toxic than ammonia
C) urea does not affect the osmolar gradient
D) less nitrogen is removed from the body
Put the steps of the process of signal transduction in the order they occur:
1. A conformational change in the signal-receptor complex activates an enzyme.
2. Protein kinases are activated.
3. A signal molecule binds to a receptor.
4. Target proteins are phosphorylated.
5. Second messenger molecules are released.
A) 1, 2, 3, 4, 5
B) 3, 1, 2, 4, 5
C) 3, 1, 5, 2, 4
D) 1, 2, 5, 3, 4
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol
disrupts microtubule formation. Surprisingly, this stops mitosis. Specifically, Taxol
must affect _____.
A) the structure of the mitotic spindle
B) anaphase
C) formation of the centrioles
D) chromatid assembly
Thalidomide, now banned for use as a sedative in pregnancy, was used in the early
1960s by many women in their first trimester of pregnancy. Some of these women gave
birth to children with arm and leg deformities, suggesting that the drug most likely
influenced _____.
A) early cleavage divisions
B) differentiation of bone tissue
C) morphogenesis
D) organogenesis
Use the following information and graph to answer the question(s) below.
The figure below depicts changes to the amount of DNA present in a recipient cell that
is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient
cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment
of the recipient’s chromosome is exchanged for a homologous fragment from the Hfr
cell’s DNA).
What is occurring at Time C that is decreasing the DNA content?
A) crossing over
B) cytokinesis
C) degradation of DNA that was not retained in the recipient’s chromosome
D) reversal of the direction of conjugation
Uniform spacing patterns in plants such as the creosote bush are most often associated
with _____.
A) patterns of high humidity
B) the random distribution of seeds
C) competitive interaction between individuals of the same population
D) the concentration of nutrients within the population’s range
The Panama Canal was completed in 1914, and its depth is about fifty feet. After 1914,
snapping shrimp species from which habitats should be most likely to form hybrids as
the result of the canal?
A) A5 and B5
B) A3 and B3
C) A1 and B1
D) A1-A3 and B1-B3 have equal likelihoods of harboring snapping shrimp species that
can hybridize.
Besides sunlight, which would be the next most important climatic factors for terrestrial
plants?
A) wind and fire
B) moisture and wind
C) temperature and wind
D) temperature and moisture
Among known plant species, which of these have been the two most commonly
occurring phenomena that have led to the origin of new species?
A) allopatric speciation and sexual selection
B) allopatric speciation and polyploidy
C) sympatric speciation and sexual selection
D) sympatric speciation and polyploidy
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
Which of the following statements about the cytoskeleton is true?
A) The cytoskeleton of eukaryotes is a static structure most resembling scaffolding used
at construction sites.
B) Although microtubules are common within a cell, actin filaments are rarely found
outside of the nucleus.
C) Movement of cilia and flagella is the result of motor proteins causing microtubules
to move relative to each other.
D) Chemicals that block the assembly of the cytoskeleton would have little effect on a
cell’s response to external stimuli.
The two molecules shown in the figure below are best described as _____.
A) enantiomers
B) structural isomers
C) cis-trans isomers
D) chain length isomers
Ingested dietary substances must cross cell membranes to be used by the body. This
process is known as _____.
A) ingestion
B) digestion
C) hydrolysis
D) absorption
Hagfish (Eptatretus cirrhauts) are a jawless marine vertebrate that are isotonic with
their environment and are considered to be osmoconformers. How might this interesting
adaptation limit the habitat that the hagfish can tolerate?
A) Hagfish are not limited by salinity.
B) Osmoconformers do not face the same pressures as osmoregulators and can live in
any marine environment.
C) Individual hagfish will adapt to different salinities over their lifetime and, therefore,
can inhabit any marine environment.
D) Hagfish habitat is limited by the salinity of the environment.
The antennae of insects have a function most similar to that of _____.
A) rhinophores
B) dorsal plummules
C) cerata
D) chemoreceptors
Metaphase is characterized by _____.
A) aligning of chromosomes on the equator
B) splitting of the centromeres
C) cytokinesis
D) separation of sister chromatids
Environmental influences appear to contribute to cellular mutations that lead to tumor
growth. For example, certain diets lead to higher incidence of colon cancers, and
overexposure to sunlight leads to higher incidence of skin cancers. The tissues in closest
contact with a carcinogen or mutagen (anything that causes genetic mutations) are
obviously the ones most likely to develop tumors. Carcinomas and melanomas account
for well over half of all cancers. What type of tissue would you guess the term
carcinoma and melanoma is most closely associated with?
A) connective
B) muscle
C) epithelial
D) nervous
Mutations in which of the following genes lead to transformations in the identity of
entire body parts?
A) segmentation genes
B) egg-polarity genes
C) homeotic genes
D) inducers