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Which of the following molecules is most involved in the transfer of genetic information from the nucleus to the cytoplasm?
Which of the following is not used for DNA synthesis?
If a trait that is not expressed in the F1 generation reappears in the F2 generation, the inheritance of the trait in question is an example of
dominance and recessiveness.
A strand of DNA with the sequence 5′-ATTCCG-3′ would have a complementary strand with the sequence
Single base changes in the coding regions of proteins can cause _______ mutations.
All of the above
Which of the following molecules functions to transfer information from one generation to the next in eukaryotes?
Which of the following changes affects more than a single amino acid in a sequence?
A frameshift mutation
Mendel concluded that each pea has two units for each character, and each gamete contains one unit. Mendel's "unit" is now referred to as a(n)
Which of the following molecules are contained in a spliceosome?
RNA and protein
If a 5′-to-3′ strand of DNA has the sequence GTCTATGCATTA, what is the template DNA strand that would be used for transcription?
When cyclin binds Cdk,
kinase activation occurs.
Asexual reproduction produces genetically identical individuals because
no meiosis or fertilization takes place.
A deoxyribonucleoside is a
deoxyribose plus a nitrogenous base.
Different forms of a gene are called
If two strains of true-breeding plants that have different alleles for a certain character are crossed, their progeny are called
the F1 generation.
The enzyme that restores the phosphodiester linkage between adjacent fragments in the lagging strand during DNA replication is
In all sexually reproducing organisms, the diploid phase of the life cycle begins at
The strands that make up DNA are antiparallel. This means that
the 5′-to-3′ direction of one strand is counter to the 5′-to-3′ direction of the other strand.
During replication, the new DNA strand is synthesized
in the 5′-to-3′ direction.
Interphase involves all of the followingexcept
the condensation of chromatin.
Microtubules that form the mitotic spindle tend to originate from or terminate in
centrioles and kinetochores.
The most important thing a living cell does is:
Replicate its DNA with high fidelity,
Why did the original "one-gene, one-enzyme" hypothesis have to be modified?
Some enzymes are made up of more than one polypeptide.
Which of the following isnot found in DNA?
A pea plant with red flowers is test crossed, and one-half of the resulting progeny have red flowers, while the other half has white flowers. Therefore, the genotype of the test-crossed parent was
How does a nucleus in G2 differ from a nucleus in G1?
The G2 nucleus has twice the amount of DNA as the G1 nucleus.
In a(n) _______ cross, genes for two different characters separate.
The DNA of a eukaryotic cell is
The transcription initiation site is located
within the promoter.
In an organism with a diploid number of 8, a gamete has _______ chromosomes, a liver cell has _______ chromosomes, and a sperm cell at meiotic anaphase I has _______ chromosomes.
4; 8; 8
The energy to move chromosomes during mitosis is provided by
The process by which information in the nucleic acid sequence is used to direct the production of a specific chain of amino acids is called
Separation of the alleles of a single gene into different gametes is called
Chargaff's rule states that
the amount of cytosine equals the amount of guanine.
Refer to the following diagram of DNA complementary base pairing. Which of the following bases would pair (from top to bottom) with the exposed 3′-end strand?
Termination of transcription involves a
The mitotic spindle is composed of
Cells that donot divide are usually arrested in
Meiosis can occur
in all sexually reproducing organisms.
DNA replication occurs
Both A and D
during both mitosis and meiosis.during S phase.
Mendel's crossing of spherical-seeded pea plants with wrinkled-seeded pea plants resulted in progeny that all had spherical seeds. This indicates that the wrinkled-seed trait is
Termination of translation requires
a stop codon positioned at the A site of the ribosome, peptidyl transferase, and a release factor.
Which of the following statements about the flow of genetic information is true?
DNA encodes information that is transcribed into RNA, and RNA encodes information that is translated into proteins.
Transcription is the process by which
an RNA molecule is synthesized from a DNA template.
Semiconservative replication of DNA involves
each of the original strands acting as a template for a new strand.
The microtubules of the mitotic spindle attach to a specialized structure in the centromere region of each chromosome called the
Why is RNA incorporated into the DNA molecule during DNA replication?
DNA polymerases can only add on to an existing strand.
A mutant strain of yeast grew well at 20°C, but not at 37°C, whereas the wild-type strain grew well at both temperatures. The mutation is an example of a
The genotype of an organism that expresses a dominant trait can be determined by
crossing the organism with a homozygous recessive organism.
Which of the following statements about prokaryotes is true?
Both b and c
The most efficient means of regulation of gene expression in these organisms is usually at the level of transcription.
By making certain proteins only when needed, they save energy and other resources.
Which of the following DNA sequences would most likely be recognized by a restriction enzyme?
If a human fetus is exposed to chemicals that lead to the overexpression of Sonic hedgehog, the baby will likely have
two "little fingers" on each hand.
Which of the following techniques or tools is best suited to determine the minimal genome of a free-living bacterium?
Selective inactivation of genes
Which of the following characteristics would not be useful in a vector?
Large size relative to the host chromosomes
If the anchor cell is destroyed inCaenorhabditis elegans,
no vulva will form.
Lowering the expression of theMyoD gene would tend to _______ the activity of cyclin-dependent kinases. This activity would tend to _______ differentiation of muscle cells.
Differentiated cells in the process of forming the liver of a mouse provide an example of
DNA is cut at specific sites by means of
In negative regulation,
transcription can be turned off when a repressor binds to the DNA near the promoter.
In eukaryotes, a promoter is the region of
DNA that binds RNA polymerase.
The expression of some genes can be regulated in part by the pattern of alternative splicing. This is an example of
In the context of metabolomics, glucose would be considered a
Transgenic cells are created via the _______ of recombinant DNA into cells.
Which of the following statements about microRNAs isfalse?
They are easy to detect.
Nucleosomes disaggregate to allow transcription and then reaggregate
by acetylation and deacetylation.
A biologist would most likely use the technique of electroporation to
coax DNA into host cells.
The HIV virus that causes AIDS is a(n)
Which of the following statements about eukaryotic genomes isfalse?
The percentage of the genome devoted to coding sequence is higher than in prokaryotic genomes.
In the absence of substance M, a hypothetical LM operon is turned off. If substance M is abundant, it can bind to the repressor, which permits the polymerase to begin transcribing the DNA. In this case, LM is a(n) _______ operon and M acts as a(n) _______.
Without maintenance methylase, the changes made by DNA methylase would not
be passed on from one generation to the next.
Craig Venter, a leader of one of the teams that sequenced the human genome, has now turned his attention to cataloging the microbial life of the oceans. His studies, which involve PCR amplification of microbial DNA and a sequencing of the PCR products, are part of a field of biology called
Single nucleotide polymorphisms (SNPs)
can be used to predict if a patient is at risk for a particular disease.
A biologist is using computer programs and mathematical tools to assemble a large sequence of DNA from the data provided by multiple parallel runs of next-generation sequencing. The term that best describes this biologist's field of study is
Sequencing of the human genome has allowed scientists to
All of the above
Some metabolic pathways are regulated in part by changes in the rate of degradation of key enzymes. This is an example of
Which of the following statements about Hox genes isfalse?
They are found only inDrosophila and a few closely related genera of flies.
Which of the following isnot a potential point of regulation of gene expression?
All of the above are potential points of gene regulation.
An engineered DNA molecule that contains sequences from cattle and sequences from bacteria would be considered to be _______ DNA.
Which of the following represents the correct gene action sequence in the body segmentation ofDrosophila?
Gap, pair rule, segment polarity
A biologist who is trying to find open reading frames in a section of DNA is working in the field of
Which of the following statements about genomes is true?
Most genes found in the genomes of complex multicellular organisms are not required for survival.
Different results are achieved when an eight-cell sea urchin embryo is bisected horizontally as opposed to when it is bisected vertically. This observation supports which of the following statements?
Polarity exists in the embryo by the eight-cell stage.
DNA sequencing is most like the natural process of
Which of the following entities act inopposite ways?
A repressor and an activator
Which of the following statements about viruses is true?
They are not cells.
Haplotype maps are based primarily on
variations at specific nucleotides.
Which of the following is an example of heterochrony?
A gene whose expression causes one segment to start growing sooner than it would in the absence of that gene
compares genes in different organisms to see how those organisms are related physiologically.
Which of the following is required for the formation of gene families?
Bacteria protect themselves from their own restriction enzymes by
adding methyl groups at restriction sites.
What type of molecule is a transcription factor?
Two-dimensional gel electrophoresis separates proteins based on _______ and _______.
In next-generation DNA sequencing technology, the PCR technique
produces many identical copies of specific DNA fragments.
Which of the following statements about the evolution of development isfalse?
All of the above are true; none is false
Which of the following would provide the best evidence for genomic equivalence?
Demonstration of totipotency from a somatic cell
MicroRNAs were first discovered in
For which of the following classes of developmental genes is the phenotype of the developing individualnot determined by the individual's genotype?
Maternal effect genes
Which of the following genomes is most likely that of a free-living prokaryote?
A genome that is 3 million bp long, arranged in a single circular chromosome, and has little repetitive DNA
Which enzyme is required to bring lactose intoE. coli cells?
The artificial selection experiments with bristle numbers in Drosophila illustrate which of the following generalities?
Populations often contain considerable genetic variation upon which selection can operate.
Which of the following best describes natural selection?
The differential survival and reproduction of individuals
Supporting the claim that a meteorite caused the mass extinction at the end of the Cretaceous period, abnormally high concentrations of _______ have been found in rocks dating from that time.
Despite inhabiting overlapping ranges, the western spotted skunk and the eastern spotted skunk do not interbreed, partly because the western species breeds in early fall and the eastern species breeds in late winter to early spring. This is an example of _______ isolation.
The half-life of carbon-14 is 5,700 years. If 10 percent of the original carbon-14 is left in a structure, that structure is _______ years old.
between 17,100 and 22,800
Most of human evolution has occurred during the
Shared derived traits are also known as
It is difficult to apply the biological species concept to groups of organisms that
Both a and d
are asexual.exist only in the fossil record.
Snakes, which lack limbs, evolved from vertebrates that had legs. This is an example of
an evolutionary reversal.
Synonymous substitutions are possible because
most amino acids are specified by more than one codon.
In a hypothetical population of sawflies, 20 percent of the population is homozygous for alleleA and 45 percent is homozygous for allele a. Assuming that A and a are the only alleles at this locus, what percent of the population is heterozygous?
Genes from many isolates of the influenza virus have been sequenced. In certain regions of the genome, nonsynonymous substitutions have been found to occur much more frequently than synonymous substitutions. From this pattern we can infer that
strong selection for change (directional selection) is acting on this gene.
The hypothesis of neutral evolution asserts that
most variability in the structure of molecules does not affect their functioning.
Mules are an example of which type of reproductive isolation?
The ratio of14C to its stable isotope, carbon-12 (12C), is relatively constant in living organisms and their environment; however, this changes once an organism dies. In a fossil less than 50,000 years old, what would the ratio of 14C to 12C be?
The ratio of14C to 12C would be lower because the 14C is not replenished after death.
Which of the following is changing most rapidly during recent history?
Carbon dioxide levels
Despite being incomplete as a whole, the fossil record is rather detailed for
The species definition that includes similarity of appearance among individual members is the basis for
the morphological species concept.
In the Dobzhansky–Muller model, an ancestral population (aabb) splits into 2 lineages. Different mutations produce different new alleles in each population (Aabb in one population, aaBb in the other). Which genotype would not be viable?
An evolutionary trend toward shorter legs is observed in a rodent. Which of the following processes is the most likely explanation for this pattern?
What was Darwin's explanation for the evolution of bright colors and other apparently useless (and potentially deleterious) but conspicuous characters in males of many species?
The evolutionary relationship among organisms is known as
If the half-life of a radioactive substance is 600 years, what fraction of the original material is left after 1,800 years?
Which of the following isnot a prezygotic reproductive isolating barrier?
Suppose you were to drill a hole toward the center of Earth. Which of the following is the correct order of the layers you would encounter?
Lithospheric plate, magma, mantle
Due to various causes, including DDT poisoning, the population size of whooping cranes was reduced to about a dozen during the 1970s. The population size has since rebounded, and there are now hundreds of whooping cranes. Which of the following would younot expect to see in the current populations of whooping cranes?
Considerable genetic polymorphism
The wasp genusNasonia contains all of the descendants of the members' common ancestor. This genus therefore would be called
Why are assemblages of fossils seen in successive geological periods so different?
Mass extinctions and the subsequent rebound of biological diversity have brought about sudden changes in the assemblages.
Oxygen in Earth's atmosphere was
generated, in part, by photosynthetic cyanobacteria.
Near the ends of several geological periods, including the Devonian, Permian, and the Triassic, sea level _______ dramatically, most likely due to _______.
fell; increased glaciation
Which of the following isnot a condition that must be met for a population to be at Hardy–Weinberg equilibrium?
Small population size
Which of the following statements about biological evolution isfalse?
Individuals in a population evolve.
Which type of speciation is most common among flowering plants?
Random genetic drift would probably have its greatest effect on a
small, isolated population.
Gene duplication can
All of the above
A small population of sawflies that was once connected to a larger one but is now isolated is no longer experiencing
Which of the following is formed when two branches diverge in a phylogenetic tree?
What is the critical distinction between allopolyploidy and autopolyploidy?
Allopolyploidy requires genetic contribution from two different parental species.
Which of the following is a likely reason for the diversification of Lake Malawai cichilds?
Both a and b
Male competition for females
Two species of monkeyflowers have diverged in the characters of their flower such that they are now pollinated by different animals. This is an example of _______ isolation.
In a hypothetical population of tree swallows, 18 individuals are homozygous for thec4 allele, 22 individuals are heterozygous for the allele, and 10 individuals lack the allele. What is the frequency of the c4 allele?
Is the basis of allopatric speciation.
The sudden disappearance of the dinosaurs some 65 mya may have been the result of
Earth's collision with a large meteorite.
If variation at a given locus has no effect on the phenotype of individuals, which of the following evolutionary processes will still occur at that locus?
Rocks that are formed when grains accumulate at the bottom of bodies of water are called _______ rocks
The sizes of horns in males of a particular beetle have an interesting distribution: the highest frequencies are around 15 millimeters and 30 millimeters, with few individuals in between. Based on this observation, which of the following modes of selection is most likely to be operating on these horns?
As adaptations for flight, the wings of bats and the wings of birds are an example of
The experiments by Rice and Salt with fruit flies showed that
speciation can be studied in the lab.
If a population with two alleles is at Hardy–Weinberg equilibrium and the frequency of one allele is 0.7, what is the heterozygote frequency?
Lateral gene transfer is the process by which
Both a and c
rapid evolutionary rates.
Both a and b
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