Put the following events of elongation in prokaryotic translation in chronological order.
1. Binding of mRNA with small ribosomal subunit
2. Recognition of initiation codon
3. Complementary base pairing between initiator codon and anticodon of initiator tRNA
4. Base pairing of the mRNA codon following the initiator codon with its
complementary tRNA
5. Attachment of the large subunit
A) 1, 2, 3, 4, 5
B) 2, 1, 4, 3, 5
C) 5, 4, 3, 2, 1
D) 1, 2, 3, 5, 4
The following questions refer to the pedigree chart in the figure below for a family,
some of whose members exhibit the dominant trait, W. Affected individuals are
indicated by a dark square or circle.
What is the genotype of individual II-5?
A) WW
B) Ww
C) ww
D) ww or Ww
The questions below refer to the following table, which compares the % sequence
homology of four different parts (two introns and two exons) of a gene that is found in
five different eukaryotic species. Each part is numbered to indicate its distance from the
promoter (for example, Intron I is the one closest to the promoter). The data reported
for species A were obtained by comparing DNA from one member of species A to
another member of species A.
% Sequence Homology
Based on the tabular data, and assuming that time advances vertically, which
phylogenetic tree is the most likely depiction of the evolutionary relationships among
these five species?
A)
B)
C)
D)
Which of the following describe all existing bacteria?
A) pathogenic, omnipresent, morphologically diverse
B) extremophiles, tiny, abundant
C) tiny, ubiquitous, metabolically diverse
D) morphologically diverse, metabolically diverse, extremophiles
Which of the following would be useful in creating a phylogenetic tree of a taxon?
I) morphological data from fossil species
II) genetic sequences from living species
III) behavioral data from living species
A) I
B) II
C) III
D) I, II, and III
The vascular bundle in the shape of a single central cylinder in a root is called the
_____.
A) cortex
B) stele
C) periderm
D) pith
Which of the following would increase the electrochemical gradient across a
membrane?
A) a sucrose-proton cotransporter
B) a proton pump
C) a potassium channel
D) both a proton pump and a potassium channel
Which of the following is one of the technical reasons why gene therapy is
problematic?
A) Most cells with an engineered gene do not produce gene product.
B) Cells with transferred genes are unlikely to replicate.
C) Transferred genes may not have appropriately controlled activity.
D) mRNA from transferred genes cannot be translated.
An organism that exhibits cephalization probably also _____.
A) is bilaterally symmetrical
B) has a coelom
C) is segmented
D) is diploblastic
A laboratory might use dideoxyribonucleotides to _____.
A) separate DNA fragments
B) produce cDNA from mRNA
C) sequence a DNA fragment
D) visualize DNA expression
Why did the F1 offspring of Mendel’s classic pea cross always look like one of the two
parental varieties?
A) No genes interacted to produce the parental phenotype.
B) Each allele affected phenotypic expression.
C) The traits blended together during fertilization.
D) One allele was dominant.
You find a plant unfamiliar to you and observe that it has vascular bundles scattered
throughout the stem cross section. What do you conclude about the plant?
A) It is probably an herbaceous eudicot.
B) It will probably get annual rings of wood.
C) It is probably a monocot.
D) It could be either a young eudicot or a monocot.
How might an ecologist test whether a species is occupying all of its fundamental niche
or only a portion of it?
A) Study the temperature range and humidity requirements of the species.
B) Observe if the niche size changes after the introduction of a similar non-native
species.
C) Measure the change in reproductive success when the species is subjected to
environmental stress.
D) Observe if the species expands its range after the removal of a competitor.
Which of the following are the only extant animals that descended directly from
dinosaurs?
A) lizards
B) crocodiles
C) birds
D) tuataras
In a biological reaction, succinate dehydrogenase catalyzes the conversion of succinate
to fumarate. The reaction is inhibited by malonic acid, a substance that resembles
succinate but cannot be acted upon by succinate dehydrogenase. Increasing the amount
of succinate molecules to those of malonic acid reduces the inhibitory effect if malonic
acid. Select the correct identification of the molecules described in the reaction.
A) Succinate dehydrogenase is the enzyme, and fumarate is the substrate in the
reaction.
B) Succinate dehydrogenase is the enzyme, and malonic acid is the substrate in the
reaction.
C) Succinate is the substrate, and fumarate is the product in the reaction.
D) Fumarate is the product, and malonic acid is a noncompetitive inhibitor in the
reaction.
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
Meroblastic cleavage occurs in _____.
A) sea urchins, but not in humans or birds
B) humans, but not in sea urchins or birds
C) birds, but not in sea urchins or humans
D) both sea urchins and birds, but not in humans
Within a differentiated B cell, the rearrangement of DNA sequences between variable
regions and joining regions is accomplished by a(n)_____.
A) RNA polymerase
B) reverse transcriptase
C) epitopase
D) recombinase
The muscles of a recently deceased human can remain in a contracted state, termed
rigor mortis, for several hours, due to the lack of _____.
A) ATP needed to break actin-myosin bonds
B) calcium ions needed to bind to troponin
C) oxygen supplies needed for myoglobin
D) sodium ions needed to fire action potentials
If a ray-finned fish is to both hover (remain stationary) in the water column and
ventilate its gills effectively, then what other structure besides its swim bladder will it
use?
A) its pectoral fins
B) its lateral line system
C) its caudal (tail) fin
D) its opercula
A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being
unable to _____.
A) respond to T-independent antigens
B) lyse tumor cells
C) stimulate a cytotoxic T cell
D) interact with a class II MHC-antigen complex
Arthropods invaded land about 100 million years before vertebrates did so. This most
clearly implies that _____.
A) arthropods evolved before vertebrates did
B) extant terrestrial arthropods are better adapted to terrestrial life than are extant
terrestrial vertebrates
C) vertebrates evolved from arthropods
D) arthropods have had more time to coevolve with land plants than have vertebrates
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+
When an animal cell is placed in a hypotonic solution and water enters the cell via
osmosis, the volume of the cell increases until it bursts. This does not happen to plant
cells, because _____.
A) they have large central vacuoles, which provide abundant space for storage of
incoming water
B) they have cell walls, which prevent the entry of water by osmosis
C) they have cell walls, which provide pressure to counteract the pressure of the
incoming water
D) certain gated channel proteins embedded in their plasma membranes open as
osmotic pressure decreases, allowing excess water to leave the cell
A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic
alternation of generations is most probably what type of alga?
A) red
B) green
C) brown
D) yellow
Phosphorylation cascades involving a series of protein kinases are useful for cellular
signal transduction because they _____.
A) are species specific
B) always lead to the same cellular response
C) amplify the original signal many times
D) counter the harmful effects of phosphatases
In most fungi, karyogamy does not immediately follow plasmogamy, which
consequently _____.
A) means that sexual reproduction can occur in specialized structures
B) results in multiple diploid nuclei per cell
C) allows fungi to reproduce asexually most of the time
D) results in heterokaryotic or dikaryotic cells
Females are typically larger and more ornamented than males where _____ occurs.
A) monogamy
B) polyandry
C) polygamy
D) polygyny
Certain proteins of the complex motor that drives bacterial flagella are modified
versions of proteins that had previously belonged to plasma membrane pumps. This
evidence supports the claim that _____.
A) natural selection produces organs that will be needed in future environments
B) the motors of bacterial flagella must have originated in other organisms
C) natural selection can produce new structures by coupling together parts of other
structures
D) bacteria that possess flagella must have lost the ability to pump certain chemicals
across their plasma membranes
The crown-of-thorns sea star, Acanthaster planci, preys on the flesh of live coral. If
coral animals are attacked by these sea stars, then what actually provides nutrition to the
sea star, and which chemical (besides the toxin within their nematocysts) do the corals
rely on for protection?
A) medusae; silica
B) exoskeleton; calcium carbonate
C) polyps; calcium carbonate
D) polyps; silica
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 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.
Which of these, if discovered among cycliophorans, would cause the most confusion
concerning our current understanding of cycliophoran taxonomy?
A) if the ciliated feeding ring is a lophophore
B) if embryos are diploblastic
C) if the body cavity is actually a pseudocoelom
D) if the organisms show little apparent cephalization