The process of photosynthesis probably originated _____.
A) in plants
B) in prokaryotes
C) in fungi
D) three separate times during evolution
Menopause is characterized by _____.
A) the loss of responsiveness by the ovaries to follicle-stimulating hormone (FSH) and
luteinizing hormone (LH)
B) a decline in production of the gonadotropin hormones by the anterior pituitary gland
C) wearing away of the uterine endometrium
D) a halt in the synthesis of gonadotropin-releasing hormone by the brain
Use the following description and table to answer the question(s) below.
Diatoms are encased in petri-platelike cases (valves) made of translucent hydrated silica
whose thickness can be varied. The material used to store excess calories can also be
varied. At certain times, diatoms store excess calories in the form of the liquid
polysaccharide, laminarin, and at other times as oil. The following are data concerning
the density (specific gravity) of various components of diatoms, and of their
environment.
Specific Gravities of Materials Relevant to Diatoms
Water’s density and, consequently, its buoyancy decrease at warmer temperatures.
Considering the impact of temperature, and the table above, in which environment
should diatoms sinking be slowest?
A) cold fresh water
B) warm fresh water
C) cold seawater
D) warm seawater
When a steroid hormone and a peptide hormone exert similar effects on a population of
target cells, then _____.
A) the steroid and peptide hormones must use the same biochemical mechanisms
B) the steroid and peptide hormones must bind to the same receptor protein
C) the steroid hormones affect the synthesis of effector proteins, whereas peptide
hormones activate effector proteins already present in the cell
D) the steroid hormones affect the activity of certain proteins within the cell, whereas
peptide hormones directly affect the processing of mRNA
The formation of the fertilization envelope requires an increase in the availability of
_____.
A) calcium ions
B) hydrogen ions
C) potassium ions
D) sodium ions
Which of the following would likely move through the lipid bilayer of a plasma
membrane most rapidly?
A) CO2
B) an amino acid
C) glucose
D) K+
A signal peptide _____.
A) directs an mRNA molecule into the cisternal space of the ER
B) terminates translation of messenger RNA
C) helps target a protein to the ER
D) signals the initiation of transcription
Alternative RNA splicing _____.
A) is a mechanism for increasing the rate of translation
B) can allow the production of proteins of different sizes and functions from a single
mRNA
C) can allow the production of similar proteins from different RNAs
D) increases the rate of transcription
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?
What is the function of the nuclear pore complex found in eukaryotes?
A) It regulates the movement of proteins and RNAs into and out of the nucleus.
B) It synthesizes the proteins required to copy DNA and make mRNA.
C) It selectively transports molecules out of the nucleus, but prevents all inbound
molecules from entering the nucleus.
D) It assembles ribosomes from raw materials that are synthesized in the nucleus.
Which of the following statements best summarizes the acid-growth hypothesis in an
actively growing shoot?
A) Auxin stimulates proton pumps in the plasma membrane and tonoplast.
B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and
makes the walls more flexible.
C) Auxins and gibberellins together act as a lubricant to help stretch cellulose
microfibrils.
D) Auxins activate aquaporins that increase turgor pressure in the cells.
The specific relationship between a legume and its mutualistic Rhizobium strain
probably depends on_____.
A) each legume having a chemical dialogue with a fungus
B) each Rhizobium strain having a form of nitrogenase that works only in the
appropriate legume host
C) each legume being found where the soil has only the Rhizobium specific to that
legume
D) specific recognition between the chemical signals and signal receptors of the
Rhizobium strain and legume species
On the diagram of the nitrogen cycle, which number represents the ammonium ion
(NH4
+)?
A) 1
B) 2
C) 3
D) 4
Which of the following statements correctly describes some aspect of protein secretion
from prokaryotic cells?
A) Prokaryotes cannot secrete proteins because they lack an endomembrane system.
B) The mechanism of protein secretion in prokaryotes is probably the same as that in
eukaryotes.
C) Proteins secreted by prokaryotes are synthesized on ribosomes bound to the
cytoplasmic surface of the plasma membrane.
D) Prokaryotes cannot secrete proteins because they lack ribosomes.
Which of the following showed their greatest diversity during the Mesozoic era, but
were a small, less diverse group during the Paleozoic era?
A) gymnosperms
B) fungi
C) flowering plants
D) mammals
Use the following information to answer the question(s) below.
Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out
aerobic photosynthesis with its two elongated “chromatophores.” The chromatophores
are contained within vesicles of the host cell, and each is derived from a
cyanobacterium, though not the same type of cyanobacterium that gave rise to the
chloroplasts of algae and plants.
Assume that some members of an aquatic species of motile, photosynthetic protists
evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing
nutrients as the fish digests food. Over time, which of the following phenotypic changes
would you expect to observe in this population of protists?
A) loss of motility
B) loss of chloroplasts
C) gain of a rigid cell wall
D) gain of meiosis
In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally
acts at the origin. Which of the following would you expect as a result of this mutation?
A) Additional proofreading will occur.
B) No replication fork will be formed.
C) Replication will occur via RNA polymerase alone.
D) Replication will require a DNA template from another source.
Use the following information to answer the question(s) below.
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.
What keeps the two populations separate?
A) temporal reproductive isolation
B) lack of hybrid viability
C) behavioral reproductive isolation
D) habitat isolation
Which bond or interaction would be difficult to disrupt when compounds are put into
water?
A) covalent bonds between carbon atoms
B) hydrogen bonds
C) ionic bonds
D) ionic and hydrogen bonds
Replication in prokaryotes differs from replication in eukaryotes for which of the
following reasons?
A) Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not.
B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic
chromosomes have many.
C) The rate of elongation during DNA replication is slower in prokaryotes than in
eukaryotes.
D) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do
not.
The following figure depicts the outline of a large fairy ring that has appeared overnight
in an open meadow, as viewed from above. The fairy ring represents the furthest
advance of this mycelium through the soil. Locations A-D are all 0.5 meters below the
soil surface.
Which location is nearest to basidiocarps?
A) A
B) B
C) C
D) D
A snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of _____.
A) diatoms
B) foraminiferans
C) ciliates
D) water molds
You briefly expose bacteria undergoing DNA replication to radioactively labeled
nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA
separates into two classes. One class of labeled DNA includes very large molecules
(thousands or even millions of nucleotides long), and the other includes short stretches
of DNA (several hundred to a few thousand nucleotides in length). These two classes of
DNA probably represent _____.
A) leading strands and Okazaki fragments
B) lagging strands and Okazaki fragments
C) Okazaki fragments and RNA primers
D) leading strands and RNA primers
Why is a pathogen generally more virulent in a new habitat?
A) Intermediate host species are more motile and transport pathogens to new areas.
B) Pathogens evolve more efficient forms of reproduction in new environments.
C) Hosts in new environments have not had a chance to become resistant to the
pathogen through natural selection.
D) New environments are almost always smaller in area so that transmission of
pathogens is easily accomplished between hosts.
Among mammals, it is generally true that _____.
A) all types of foods begin their enzymatic digestion in the mouth
B) after leaving the oral cavity, the bolus enters the larynx
C) the epiglottis prevents swallowed food from entering the trachea
D) the trachea leads to the esophagus and then to the stomach
Which of the following is true of osmosis?
A) Osmosis only takes place in red blood cells.
B) Osmosis is an energy-demanding or “active” process.
C) In osmosis, water moves across a membrane from areas of lower solute
concentration to areas of higher solute concentration.
D) In osmosis, solutes move across a membrane from areas of lower water
concentration to areas of higher water concentration.
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
Which of the following problems with animal cloning might result in premature death
of the clones?
A) use of pluripotent instead of totipotent stem cells
B) use of nuclear DNA as well as mtDNA
C) abnormal gene regulation due to variant methylation
D) the indefinite replication of totipotent stem cells
Some regions of the plasma membrane, called lipid rafts, have a higher concentration of
cholesterol molecules. At higher temperatures, these regions _____.
A) are more fluid than the surrounding membrane
B) are less fluid than the surrounding membrane
C) detach from the plasma membrane and clog arteries
D) have higher rates of lateral diffusion of lipids and proteins into and out of these
regions
Use the following description to answer the question(s) below.
While on an intersession course in tropical ecology, Kris pulls a large, snakelike
organism from a burrow (the class was granted a collecting permit). The 1-meter-long
organism has smooth skin, which appears to be segmented. It has two tiny eyes that are
hard to see because they seem to be covered by skin. Kris brings it back to the lab at the
field station, where it is a source of puzzlement to the class. Kris says that it is a giant
oligochaete worm; Shaun suggests it is a legless amphibian; Kelly proposes it belongs
to a snake species that is purely fossorial (lives in a burrow).
The class decided to humanely euthanize the organism and subsequently dissect it.
Having decided that it was probably not a reptile, two of their original hypotheses
regarding its identity remained. Which of the following, if observed, should help them
arrive at a conclusive answer?
A) presence of moist, highly vascularized skin
B) presence of lungs
C) presence of a nerve cord
D) presence of a digestive system with two openings
Carnivorous plants have evolved mechanisms that trap and digest small animals. The
products of this digestion are used to supplement the plant’s supply of_____.
A) energy
B) carbohydrates
C) lipids and steroids
D) nitrogen and other minerals