Osteoporosis is a condition in which the density of bones is decreased so much that the
individual is at a higher risk of fractures. The more calcium in the bones, the better the
bone density. Which of the following would produce the greatest increase in bone
calcium levels?
A) calcitonin injection
B) calcitonin receptor blocker
C) parathyroid hormone injection
D) glucagon receptor blocker
A physician finds that a nine-year-old male patient is entering puberty much earlier than
is usual. Such a condition is most likely the result of a tumor in the _____.
A) hypothalamus, producing elevated levels of testosterone
B) anterior pituitary, producing elevated levels of testosterone
C) testes, producing elevated levels of estrogen
D) anterior pituitary, producing elevated levels of gonadotropin-stimulating hormone
During mammalian labor and delivery, the contraction of uterine muscles is enhanced
by oxytocin. This is an example of _____.
A) a negative feedback system
B) a hormone that acts in an antagonistic way with another hormone
C) a hormone that is involved in a positive feedback loop
D) signal transduction immediately changing gene expression in its target cells
An otherwise healthy student in your class is infected with EBV, the virus that causes
infectious mononucleosis. The same student had already been infected when she was a
child, at which time she had merely experienced a mild sore throat and swollen lymph
nodes in her neck. This time, though infected, she does not get sick.
The EBV antigen fragments will be presented by the virus-infected cells along with
_____.
A) a complement
B) antibodies
C) class I MHC molecules
D) class II MHC molecules
What determines whether a carbon atom’s covalent bonds to other atoms are in a
tetrahedral configuration or a planar configuration?
A) the presence or absence of bonds with oxygen atoms
B) the presence or absence of double bonds between the carbon atom and other atoms
C) the polarity of the covalent bonds between carbon and other atoms
D) the solvent in which the organic molecule is dissolved
Which of the following statements are fundamental to the clonal-selection theory of
how the adaptive immune system functions?
I) Each lymphocyte has a unique membrane receptor that recognizes one antigen.
II) When the lymphocyte binds an antigen, it is activated and begins dividing to form
many identical copies of itself.
III) Cloned lymphocytes have slight differences and are selected by the spleen for
removal if they do not bind an antigen.
IV) Cloned cells descend from an activated lymphocyte and persist even after the
pathogen is eliminated.
A) only I and III
B) only II and IV
C) only I, II, and IV
D) only II, III, and IV
If ATP production in a human kidney was suddenly halted, urine production would
_____.
A) decrease, and the urine would be hypoosmotic compared to plasma
B) increase, and the urine would be isoosmotic compared to plasma
C) increase, and the urine would be hyperosmotic compared to plasma
D) decrease, and the urine would be isoosmotic compared to plasma
An original section of DNA has the base sequence AGCGTTACCGT. A mutation in this
DNA strand results in the base sequence AGGCGTTACCGT. This change represents
_____.
A) a missense mutation
B) a point mutation
C) a silent mutation
D) frameshift mutation
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.
A crucial photosynthetic gene of the cyanobacterium that gave rise to the
chromatophore is called psaE. This gene is present in the nuclear genome of the
cercozoan, but is not in the genome of the chromatophore. This is evidence of _____.
A) reciprocal mutations in the chromatophore and nuclear genomes
B) horizontal gene transfer from bacterium to eukaryotes
C) genetic recombination involving a protist and an archaean
D) transduction by a phage that infects both prokaryotes and eukaryotes
If a doctor attempts to trigger the patellar tendon reflex and a lack of response occurs,
what are potential regions where pathology might exist?
I) the brain
II) the knee
III) the spinal cord
A) only I
B) only II
C) only III
D) only II and III
What is the estimated frequency of allele A in the gene pool?
A) 0.25
B) 0.50
C) 0.75
D) 0.125
What would happen to the seasons if the Earth were tilted 35 degrees off its orbital
plane instead of the usual 23.5 degrees?
A) The seasons would disappear.
B) Winters and summers would be more severe.
C) Winters and summers would be less severe.
D) The seasons would be shorter.
The approach to estimating phylogenetic trees is most like the approach of which
species concept?
A) morphological species concept
B) biological species concept
C) phylogenetic species concept
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
The most recently discovered phylum in the animal kingdom (1995) is the phylum
Cycliophora. It includes three species of tiny organisms that live in large numbers on
the outsides of the mouthparts and appendages of lobsters. The feeding stage
permanently attaches to the lobster via an adhesive disk and collects scraps of food
from its host’s feeding by capturing the scraps in a current created by a ring of cilia. The
body is sac-like and has a U-shaped intestine that brings the anus close to the mouth.
Cycliophorans are coelomates, do not molt (though their host does), and their embryos
undergo spiral cleavage.
If harboring large populations of cycliophorans neither helps nor harms their lobster
hosts, then cycliophorans can be properly considered to be _____.
1. parasites
2. mutualists
3. commensals
4. symbionts
5. endosymbionts
A) 1 and 4
B) 3 and 4
C) 2 and 5
D) 3 and 5
How are two different species most likely to evolve from one ancestral species?
A) sympatrically, by a point mutation affecting morphology or behavior
B) sympatrically, due to extensive inbreeding
C) allopatrically, due to extensive inbreeding
D) allopatrically, after the ancestral species has split into two populations
Cell membranes are asymmetrical. Which of the following statements is the most likely
explanation for the membrane’s asymmetrical nature?
A) Since the cell membrane forms a border between one cell and another in tightly
packed tissues such as epithelium, the membrane must be asymmetrical
B) Since cell membranes communicate signals from one organism to another, the cell
membranes must be asymmetrical.
C) The two sides of a cell membrane face different environments and carry out different
functions.
D) Proteins only function on the cytoplasmic side of the cell membrane, which results
in the membrane’s asymmetrical nature.
Examine the figure above, which notes the average barrels of oil used per person per
year in different countries. What can be concluded?
A) Residents in warmer climates use more energy per person.
B) Residents of industrialized countries use more energy per person.
C) Residents of more populated countries use more energy per person.
D) English-speaking countries tend to use more energy per person.
Referring to the accompanying figure, oxygen would inhibit the CO2 fixation reactions
in _____.
A) cell I only
B) cell II only
C) neither cell I nor cell II
D) both cell I and cell II
Which of the following observations provides the strongest evidence against root
pressure being the principal mechanism of water transport in the xylem?
A) Not all soils have high concentrations of ions.
B) Root pressure requires movement of water into the xylem from surrounding cells in
the roots.
C) Over long distances, the force of root pressure is not enough to overcome the force
of gravity.
D) There is no water potential gradient between roots and shoots.
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 release factor (RF) _____.
A) binds to the stop codon in the A site in place of a tRNA
B) releases the amino acid from its tRNA to allow the amino acid to form a peptide
bond
C) supplies a source of energy for termination of translation
D) releases the ribosome from the ER to allow polypeptides into the cytosol
After cytokinesis occurs in budding yeasts, the daughter cell has a _____.
A) similar nucleus and more cytoplasm than the mother cell
B) smaller nucleus and less cytoplasm than the mother cell
C) larger nucleus and less cytoplasm than the mother cell
D) similar nucleus and less cytoplasm than the mother cell
The feeding stage of cycliophorans _____.
1. is autotrophic
2. is sessile
3. captures food in a manner similar to that of animals with lophophores
4. shows radial symmetry
A) 1 and 2
B) 1 and 3
C) 2 and 4
D) 1, 2, and 3
Proposed Number of HoxGenes in Various Extant and Extinct Animals
What conclusion is apparent from the data in the table above?
A) Land animals have more Hox genes than do those that live in water.
B) All bilaterian phyla have had the same degree of expansion in their numbers of Hox
genes.
C) The expansion in number of Hox genes throughout vertebrate evolution cannot be
explained merely by three duplications of the ancestral vertebrate Hox cluster.
D) Extant insects all have seven Hox genes.
The oak tree fungal pathogen, Phytophthora ramorum, has migrated eight hundred
kilometers in fifteen years. West Nile virus spread from New York State to forty-six
other states in five years. The difference in the rate of spread is probably related to
_____.
A) the lethality of each pathogen
B) the mobility of their hosts
C) the fact that viruses are very small
D) innate resistance
What is the main structural difference between enveloped and nonenveloped viruses?
A) Enveloped viruses have their genetic material enclosed by a layer made only of
protein.
B) Nonenveloped viruses have only a phospholipid membrane, while enveloped viruses
have two membranes, the other one being a protein capsid.
C) Enveloped viruses have a phospholipid membrane outside their capsid, whereas
nonenveloped viruses do not have a phospholipid membrane.
D) Both types of viruses have a capsid and phospholipid membrane; but in the
nonenveloped virus the genetic material is between these two membranes, while in the
enveloped virus the genetic material is inside both membranes.
Which of the following might result in a human zygote with 45 chromosomes?
A) an error in either egg or sperm meiotic anaphase
B) failure of the egg nucleus to be fertilized by the sperm
C) failure of an egg to complete meiosis II
D) incomplete cytokinesis during spermatogenesis after meiosis I
Cells are _____.
A) only found in pairs, because single cells cannot exist independently
B) limited in size to 200 and 500 micrometers in diameter
C) characteristic of eukaryotic but not prokaryotic organisms
D) characteristic of prokaryotic and eukaryotic organisms
Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a
consequence of which of the following?
A) the evolution of telomerase enzyme
B) DNA polymerase that cannot replicate the leading strand template to its end
C) gaps left at the end of the lagging strand
D) gaps left at the end of the lagging strand because of the need for a primer
Labor contractions can be increased by the medical use of a synthetic drug that mimics
the action of _____.
A) inhibin
B) luteinizing hormone
C) oxytocin
D) prolactin
Why are action potentials usually conducted in one direction?
A) The nodes of Ranvier conduct potentials in one direction.
B) The brief refractory period prevents reopening of voltage-gated Na+ channels.
C) The axon hillock has a higher membrane potential than the terminals of the axon.
D) Voltage-gated channels for both Na+ and K+ open in only one direction.