Helicobacter pylori is a bacterial organism that causes ulcers and digestive
disturbances. How might they survive the acid pH of the stomach?
A) They secrete buffers to neutralize acid.
B) They burrow under the mucus layer that covers the stomach epithelium.
C) They take over the parietal cells.
D) They release chemicals that decrease acid production in the stomach.
The following diagram is of a cross section of a plant leaf. Use the diagram to answer
the question(s) below.
The main function associated with structure X is _____.
A) absorption of carbon dioxide
B) retention of water
C) collection of light
D) release of carbon dioxide
The following questions refer to this phylogenetic tree, depicting the origins of life and
of the three domains. Horizontal lines indicate instances of gene or genome transfer.
A possible phylogenetic tree for the three domains of life.
If the early history of life on Earth is accurately depicted by the figure above, then
which statement is most in agreement with the hypothesis proposed by this tree?
A) The last universal common ancestor of all extant species is one individual species.
B) The origin of the three domains appears as a polytomy.
C) Archaean genomes should not contain genes that originated in bacteria, and vice
versa.
D) Eukaryotes are more closely related to archaeans than to bacteria.
When are atoms most stable?
A) when they have the fewest possible valence electrons
B) when they have the maximum number of unpaired electrons
C) when all of the electron orbitals in the valence shell are filled
D) when all electrons are paired
The fruit of the mistletoe, a parasitic angiosperm, is a one-seeded berry. In members of
the genus Viscum, the outside of the seed is viscous (sticky), which permits the seed to
adhere to surfaces such as the branches of host plants or the beaks of birds. What should
be expected of the fruit if the viscosity of Viscum seeds is primarily an adaptation for
dispersal rather than an adaptation for infecting host plant tissues? It should ______.
A) be drab in color
B) be colored so as to provide it with camouflage
C) be nutritious to the dispersing organisms
D) secrete enzymes that can digest bark
When a cell is in equilibrium with its environment, which of the following occurs for
substances that can diffuse through the cell?
A) There is random movement of substances into and out of the cell.
B) There is directed movement of substances into and out of the cell.
C) There is no movement of substances into and out of the cell.
D) All movement of molecules is directed by active transport.
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom
(not a proton), the molecule becomes _____.
A) dehydrogenated
B) oxidized
C) reduced
D) redoxed
From the figure above, what can we determine about the location of the food source?
A) The waggle dance in the top figure indicates that the food is directly under the hive.
B) The waggle dance in the bottom figure indicates that the food is to the west of the
hive.
C) The waggle dance in the top figure indicates that the food is close to the hive.
D) The waggle dance in the bottom figure indicates that the food is 90 degrees to the
right of the Sun.
Use the following information to answer the question(s) below.
A part of an mRNA molecule with the following sequence is being read by a ribosome:
CCG-ACG (mRNA). The following charged transfer RNA molecules (with their
anticodons shown in the to direction) are available. Two of them can correctly
match the mRNA so that a dipeptide can form.
The dipeptide that will form will be _____.
A) cysteine-alanine
B) proline-threonine
C) glycine-cysteine
D) alanine-alanine
In animals, what is the difference between reproductive cloning and therapeutic
cloning?
A) Reproductive cloning uses totipotent cells, whereas therapeutic cloning does not.
B) Reproductive cloning uses embryonic stem cells, whereas therapeutic cloning does
not.
C) Therapeutic cloning uses nuclei of adult cells transplanted into enucleated
nonfertilized eggs.
D) Therapeutic cloning supplies cells for repair of diseased or injured organs.
Excessive formation of uric acid crystals in humans leads to _____.
A) a condition called diabetes, where excessive urine formation occurs
B) a condition of insatiable thirst and excessive urine formation
C) gout, a painful inflammatory disease that primarily affects the joints
D) osteoarthritis, an inevitable consequence of aging
Assuming that they all belong to the same plant, arrange the following structures from
largest to smallest (or from most inclusive to least inclusive).
1. spores
2. sporophylls
3. sporophytes
4. sporangia
A) 2, 4, 3, 1
B) 2, 3, 4, 1
C) 3, 1, 4, 2
D) 3, 2, 4, 1
Neurotransmitters affect postsynaptic cells by _____.
I) initiating signal transduction pathways in the cells
II) causing molecular changes in the cells
III) affecting ion-channel proteins
IV) altering the permeability of the cells
A) I and III
B) II and IV
C) III and IV
D) I, II, III, and IV
Neutral theory proposes that _____.
A) molecular clocks are more reliable when the surrounding pH is close to 7.0
B) most mutations of highly conserved DNA sequences should have no functional
effect
C) DNA is less susceptible to mutation when it codes for amino acid sequences whose
side groups (or R-groups) have a neutral pH
D) a significant proportion of mutations are not acted upon by natural selection
The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal
cells are all external to the plasma membrane. Which of the following is a characteristic
common to all of these extracellular structures?
A) They must block water and small molecules to regulate the exchange of matter and
energy with their environment.
B) They must provide a rigid structure that maintains an appropriate ratio of cell surface
area to volume.
C) They are constructed of polymers that are synthesized in the cytoplasm and then
transported out of the cell.
D) They are composed of a mixture of lipids and nucleotides.
Fruit ripening represents an example of positive feedback. Which one of the following
statements accurately justifies why the process of fruit ripening involves positive
feedback?
A) Once seeds have reached maturity, chemical signals increase enzymatic activity in
fruit to convert sugars into starches, thicken pulp, and maintain color in the fruit.
B) Once seeds have reached maturity, chemical signals block enzymatic steps that
normally convert sugars into starches and sugars accumulate from photosynthetic
activity within the fruit.
C) Chemical signals initiate a process that triggers enzymatic activity, which involves
converting starches into sugars, softening of pulp, and color change of fruit.
D) Chemical signals shut down enzymatic activity within the fruit, which results in
breakdown of starches into sugars, softening of pulp, and color change of fruit.
Of the following ecosystem types, which have been impacted the most by humans?
A) wetland and riparian
B) desert and high alpine
C) taiga and second-growth forests
D) tundra and arctic
A disease that destroys the adrenal cortex should lead to an increase in the plasma levels
of _____.
A) glucocorticoid hormones
B) epinephrine
C) adrenocorticotropic hormone (ACTH)
D) acetylcholine
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 cellulose-digesting organisms in the gut of a termite
and the termite?
A) +/+
B) +/o
C) +/-
D) o/o
You are most likely to observe coprophagy in _____.
A) carnivores
B) herbivores
C) fluid feeders
D) suspension feeders
While examining a rock surface, you have discovered an interesting new organism.
Which of the following criteria will allow you to classify the organism as belonging to
Bacteria but not Archaea or Eukarya?
A) Cell walls are made primarily of peptidoglycan.
B) The organism does not have nucleus.
C) The lipids in its plasma membrane consist of glycerol bonded to straight-chain fatty
acids.
D) It can survive at a temperature over 100C.
Which of the following is true of a species that has a chromosome number of 2n = 16?
A) The species is diploid with 32 chromosomes per cell.
B) The species has 16 sets of chromosomes per cell.
C) Each diploid cell has eight homologous pairs.
D) A gamete from this species has four chromosomes.
You are working on a team that is designing a new drug. For this drug to work, it must
enter the cytoplasm of specific target cells. Which of the following would be a factor
that determines whether the molecule selectively enters the target cells?
A) hydrophobicity of the drug molecule
B) lack of charge on the drug molecule
C) similarity of the drug molecule to other molecules transported by the target cells
D) lipid composition of the target cells’ plasma membrane
Which of the following most accurately describes selective permeability?
A) An input of energy is required for transport.
B) Lipid-soluble molecules pass through a membrane.
C) There must be a concentration gradient for molecules to pass through a membrane.
D) Only certain molecules can cross a cell membrane.
Which of the following statements would be LEAST acceptable to most zoologists?
A) The first fossils resembling lancelets appeared in the fossil record around 530
million years ago.
B) Recent work in molecular systematics supports the hypothesis that lancelets are the
basal clade of chordates.
C) The extant lancelets are the immediate ancestors of the fishes.
D) Lancelets display the same method of swimming as do fishes.
An individual mixotroph loses its plastids, yet continues to survive. Which of the
following most likely accounts for its continued survival?
A) It relies on photosystems that float freely in its cytosol.
B) It must have gained extra mitochondria when it lost its plastids.
C) It engulfs organic material by phagocytosis or by absorption.
D) It has an endospore.
Amino acids are acids because they always possess which functional group?
A) amino
B) carbonyl
C) carboxyl
D) phosphate
Use this information to answer the question(s) below.
A researcher found a method she could use to manipulate and quantify phosphorylation
and methylation in embryonic cells in culture.
In one set of experiments she succeeded in increasing acetlylation of histone tails.
Which of the following results would she most likely see?
A) increased chromatin condensation
B) decreased chromatin condensation
C) decreased binding of transcription factors
D) inactivation of the selected genes
How is the recipient cell different at Time D than it was at Time A?
A) It has a greater number of genes.
B) It has a greater mass of DNA.
C) It has a different sequence of base pairs.
D) It contains bacteriophage DNA.
What is the difference between the leading strand and the lagging strand in DNA
replication?
A) The leading strand is synthesized in the → direction in a discontinuous fashion,
while the lagging strand is synthesized in the → direction in a continuous fashion.
B) The leading strand is synthesized continuously in the → direction, while the
lagging strand is synthesized discontinuously in the → direction.
C) The leading strand requires an RNA primer, whereas the lagging strand does not.
D) There are different DNA polymerases involved in elongation of the leading strand
and the lagging strand.