Chapter 16, 17, 18 Unit Test
What are prions? A) misfolded versions of normal brain protein B) tiny molecules of RNA that infect plants C) viral DNA that has had to attach itself to the host genome D) viruses that invade bacteria E) a mobile segment of DNA
A) misfolded versions of normal brain protein
What characteristics of electron microscopes make them most useful for studying viruses? A) high energy electrons with high penetrance B) requirement that specimens be viewed in a vacuum C) necessity for specimens to be dry and fixed D) shorter wavelengths providing higher resolution E) use of magnetic fields to focus electrons
D) shorter wavelengths providing higher resolution
What is it that can be duplicated in a genome? A) DNA sequences above a minimum size only B) DNA sequences below a minimal size only C) entire chromosomes only D) entire sets of chromosomes only E) sequences, chromosomes, or sets of chromosomes
E) sequences, chromosomes, or sets of chromosomes
What is the difference between a linkage map and a physical map? A) For a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs (bp). B) For a physical map, the ATCG order and sequence must be achieved, but not for the linkage map. C) For a linkage map, it is shown how each gene is linked to every other gene. D) For a physical map, the distances must be calculable in units such as nanometers. E) There is no difference between the two except in the type of pictorial representation.
A) For a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs (bp).
Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for that domain of a protein that binds to DNA in a regulatory developmental process. Which of the following would you then expect? A) That homeotic genes are selectively expressed over developmental time. B) That a homeobox containing gene has to be a developmental regulator. C) That homeoboxes cannot be expressed in non-homeotic genes. D) That all organisms must have homeotic genes. E) That all organisms must have homeobox containing genes.
A) That homeotic genes are selectively expressed over developmental time.
In comparing the genomes of humans and those of other higher primates, it is seen that humans have a large metacentric pair we call chromosome #2 among our 46 chromosomes, while the other primates of this group have 48 chromosomes and any pair like the human #2 pair is not present; instead the primate groups each have two pairs of midsize acrocentric chromosomes. What is the most likely explanation? A) The ancestral organism had 48 chromosomes and at some point a centric fusion event occurred and provided some selective advantage. B) The ancestral organism had 46 chromosomes, but primates evolved when one of the pairs broke in half. C) At some point in evolution, human ancestors and primate ancestors were able to mate and produce fertile offspring, making a new species. D) Chromosome breakage results in additional centromeres being made in order for meiosis to proceed successfully. E) Transposable elements transferred significantly large segments of the chromosomes to new locations.
A) The ancestral organism had 48 chromosomes and at some point a centric fusion event occurred and provided some selective advantage.
What is it about short tandem repeat DNA that makes it useful for DNA fingerprinting? A) The number of repeats varies widely from person to person or animal to animal. B) The sequence of DNA that is repeated varies significantly from individual to individual. C) The sequence variation is acted upon differently by natural selection in different environments. D) Every racial and ethnic group has inherited different short tandem repeats.
A) The number of repeats varies widely from person to person or animal to animal.
Why are viruses referred to as obligate parasites? A) They cannot reproduce outside of a host cell. B) Viral DNA always inserts itself into host DNA. C) They invariably kill any cell they infect. D) They can incorporate nucleic acids from other viruses. E) They must use enzymes encoded by the virus itself.
A) They cannot reproduce outside of a host cell.
Which of the following is the best predictor of how much damage a virus causes? A) ability of the infected cell to undergo normal cell division B) ability of the infected cell to carry on translation C) whether the infected cell produces viral protein D) whether the viral mRNA can be transcribed E) how much toxin the virus produces
A) ability of the infected cell to undergo normal cell division
Homeotic genes A) encode transcription factors that control the expression of genes responsible for specific anatomical structures. B) are found only in Drosophila and other arthropods. C) are the only genes that contain the homeobox domain. D) encode proteins that form anatomical structures in the fly. E) are responsible for patterning during plant development.
A) encode transcription factors that control the expression of genes responsible for specific anatomical structures.
Bioinformatics can be used to scan sequences for probable genes looking for start and stop sites for transcription and for translation, for probable splice sites, and for sequences known to be found in other known genes. Such sequences containing these elements are called A) expressed sequence tags. B) cDNA. C) multigene families. D) proteomes. E) short tandem repeats.
A) expressed sequence tags.
Which of the following can be effective in preventing viral infection in humans? A) getting vaccinated B) taking nucleoside analogs that inhibit transcription C) taking antibiotics D) applying antiseptics E) taking vitamins
A) getting vaccinated
Which of the following molecules make up the viral envelope? A) glycoproteins B) proteosugars C) carbopeptides D) peptidocarbs E) carboproteins
A) glycoproteins
Most human-infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis? A) rabies B) herpesvirus C) smallpox D) HIV E) hepatitis virus
A) rabies
What is the name given to viruses that are single-stranded RNA that acts as a template for DNA synthesis? A) retroviruses B) proviruses C) viroids D) bacteriophages E) lytic phages
A) retroviruses
The host range of a virus is determined by A) the proteins on its surface and that of the host. B) whether its nucleic acid is DNA or RNA. C) the proteins in the hostʹs cytoplasm. D) the enzymes produced by the virus before it infects the cell. E) the enzymes carried by the virus.
A) the proteins on its surface and that of the host.
One of the characteristics of retrotransposons is that A) they code for an enzyme that synthesizes DNA using an RNA template. B) they are found only in animal cells. C) they generally move by a cut-and-paste mechanism. D) they contribute a significant portion of the genetic variability seen within a population of gametes. E) their amplification is dependent on a retrovirus.
A) they code for an enzyme that synthesizes DNA using an RNA template.
The difference between vertical and horizontal transmission of plant viruses is that A) vertical transmission is transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant. B) vertical transmission is the spread of viruses from upper leaves to lower leaves of the plant, and horizontal transmission is the spread of a virus among leaves at the same general level. C) vertical transmission is the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size. D) vertical transmission is the transfer of DNA from one type of plant virus to another, and horizontal transmission is the exchange of DNA between two plant viruses of the same type. E) vertical transmission is the transfer of DNA from a plant of one species to a plant of a different species, and horizontal transmission is the spread of viruses among plants of the same species.
A) vertical transmission is transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant.
Why is it unwise to try to relate an organismʹs complexity with its size or number of cells? A) A very large organism may be composed of very few cells or very few cell types. B) A single-celled organism, such as a bacterium or a protist, still has to conduct all the complex life functions of a large multicellular organism. C) A single-celled organism that is also eukaryotic, such as a yeast, still reproduces mitotically. D) A simple organism can have a much larger genome. E) A complex organism can have a very small and simple genome.
B) A single-celled organism, such as a bacterium or a protist, still has to conduct all the complex life functions of a large multicellular organism.
Barbara McClintock, famous for discovering that genes could move within genomes, had her meticulous work ignored for nearly 4 decades, but eventually won the Nobel Prize. Why was her work so distrusted? A) The work of women scientists was still not allowed to be published. B) Geneticists did not want to lose their cherished notions of DNA stability. C) There were too many alternative explanations for transposition. D) She allowed no one else to duplicate her work. E) She worked only with maize, which was considered ʺmerelyʺ a plant.
B) Geneticists did not want to lose their cherished notions of DNA stability.
What is the function of reverse transcriptase in retroviruses? A) It hydrolyzes the host cellʹs DNA. B) It uses viral RNA as a template for DNA synthesis. C) It converts host cell RNA into viral DNA. D) It translates viral RNA into proteins. E) It uses viral RNA as a template for making complementary RNA strands.
B) It uses viral RNA as a template for DNA synthesis.
Why do RNA viruses appear to have higher rates of mutation? A) RNA nucleotides are more unstable than DNA nucleotides. B) Replication of their genomes does not involve the proofreading steps of DNA replication. C) RNA viruses replicate faster. D) RNA viruses can incorporate a variety of nonstandard bases. E) RNA viruses are more sensitive to mutagens.
B) Replication of their genomes does not involve the proofreading steps of DNA replication.
Unequal crossing over during Prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, known as hemoglobin Lepore, is known in the human population. Hemoglobin Lepore has a deleted set of amino acids. If it was caused by unequal crossing over, what would be an expected consequence? A) If it is still maintained in the human population, hemoglobin Lepore must be selected for in evolution. B) There should also be persons born with, if not living long lives with, an anti-Lepore mutation or duplication. C) Each of the genes in the hemoglobin gene family must show the same deletion. D) The deleted gene must have undergone exon shuffling E) The deleted region must be located in a different area of the individualʹs genome.
B) There should also be persons born with, if not living long lives with, an anti-Lepore mutation or duplication.
Which of the following describes plant virus infections? A) They can be controlled by the use of antibiotics. B) They are spread throughout a plant by passing through the plasmodesmata. C) They have little effect on plant growth. D) They are seldom spread by insects. E) They can never be inherited from a parent.
B) They are spread throughout a plant by passing through the plasmodesmata.
Which of the following represents a difference between viruses and viroids? A) Viruses infect many types of cells, whereas viroids infect only prokaryotic cells. B) Viruses have capsids composed of protein, whereas viroids have no capsids. C) Viruses contain introns; viroids have only exons. D) Viruses always have genomes composed of DNA, whereas viroids always have genomes composed of RNA. E) Viruses cannot pass through plasmodesmata; viroids can.
B) Viruses have capsids composed of protein, whereas viroids have no capsids.
What is bioinformatics? A) a technique using 3D images of genes in order to predict how and when they will be expressed B) a method that uses very large national and international databases to access and work with sequence information C) a software program available from NIH to design genes D) a series of search programs that allow a student to identify who in the world is trying to sequence a given species E) a procedure that uses software to order DNA sequences in a variety of comparable ways
B) a method that uses very large national and international databases to access and work with sequence information
Viral envelopes can best be analyzed with which of the following techniques? A) transmission electron microscopy B) antibodies against specific proteins not found in the host membranes C) staining and visualization with the light microscope D) use of plaque assays for quantitative measurement of viral titer E) immunofluorescent tagging of capsid proteins
B) antibodies against specific proteins not found in the host membranes
RNA viruses require their own supply of certain enzymes because A) host cells rapidly destroy the viruses. B) host cells lack enzymes that can replicate the viral genome. C) these enzymes translate viral mRNA into proteins. D) these enzymes penetrate host cell membranes. E) these enzymes cannot be made in host cells.
B) host cells lack enzymes that can replicate the viral genome.
What does the field often called ʺevo-devoʺ study? A) whether or not development is an evolutionary process B) how developmental processes have evolved C) whether or not all animals have developmental regulation D) whether the pattern of human development evolved early or late E) whether or not there are specific genes controlling development
B) how developmental processes have evolved
Antiviral drugs that have become useful are usually associated with which of the following properties? A) ability to remove all viruses from the infected host B) interference with the viral reproduction C) prevention of the host from becoming infected D) removal of viral proteins E) removal of viral mRNAs
B) interference with the viral reproduction
*** Next Chapter For mapping studies of genomes, most of which were far along before 2000, the 3 -stage method was often used. Which is the usual order in which the stages were performed, assuming some overlap of the three? A) genetic map, sequencing of fragments, physical map B) linkage map, physical map, sequencing of fragments C) sequencing of entire genome, physical map, genetic map D) cytogenetic linkage, sequencing, physical map E) physical map, linkage map, sequencing
B) linkage map, physical map, sequencing of fragments
What is proteomics? A) the linkage of each gene to a particular protein B) the study of the full protein set encoded by a genome C) the totality of the functional possibilities of a single protein D) the study of how amino acids are ordered in a protein E) the study of how a single gene activates many proteins
B) the study of the full protein set encoded by a genome
Which of the following seems to be the known upper and lower size limits of genomes? A) 1—2900 Mb (million base pairs) B) 1,500—40,000 Mb C) 1—580,000 Mb D) 100—120,000 Mb E) 100—200,000 Mb
C) 1—580,000 Mb
Alu elements account for about 10% of the human genome. What does this mean? A) Alu elements cannot be transcribed into RNA. B) Alu elements evolved in very ancient times, before mammalian radiation. C) Alu elements represent the result of transposition. D) No Alu elements are found within individual genes. E) Alu elements are cDNA and therefore related to retrotransposons.
C) Alu elements represent the result of transposition.
Which of the following is a representation of gene density? A) Humans have 2,900 Mb per genome. B) C. elegans has ~20,000 genes. C) Humans have ~25,000 genes in 2,900 Mb. D) Humans have 27,000 bp in introns. E) Fritillaria has a genome 40 times the size of a human.
C) Humans have ~25,000 genes in 2,900 Mb.
If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities? A) I B) II C) III D) IV E) either II or IV
C) III
In order to determine the probable function of a particular sequence of DNA in humans, what might be the most reasonable approach? A) Prepare a knockout mouse without a copy of this sequence and examine the mouse phenotype. B) Genetically engineer a mouse with a copy of this sequence and examine its phenotype. C) Look for a reasonably identical sequence in another species, prepare a knockout of this sequence in that species and look for the consequences. D) Prepare a genetically engineered bacterial culture with the sequence inserted and assess which new protein is synthesized. E) Mate two individuals heterozygous for the normal and mutated sequences.
C) Look for a reasonably identical sequence in another species, prepare a knockout of this sequence in that species and look for the consequences.
If humans have 2,900 Mb, a specific member of the lily family has 120,000 Mb, and a yeast has ~13 Mb, why canʹt this data allow us to order their evolutionary significance? A) Size matters less than gene density. B) Size does not compare to gene density. C) Size does not vary with gene complexity. D) Size is mostly due to ʺjunkʺ DNA. E) Size is comparable only within phyla.
C) Size does not vary with gene complexity.
Why is it preferable to use large computers and databases in searching for individual genes, rather than testing each sequence for possible function? A) Testing for function would require too many cells. B) Testing for function would require knowing the species, its life stage, and its phylogeny. C) Testing for function would require knowing where a particular gene starts and ends and how it is regulated. D) Use of computer databases is intellectually less rigorous. E) The computer data can be sent to more labs.
C) Testing for function would require knowing where a particular gene starts and ends and how it is regulated.
Which of the following statements describes the lysogenic cycle of lambda (λ) phage? A) After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. B) Most of the prophage genes are activated by the product of a particular prophage gene. C) The phage genome replicates along with the host genome. D) Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic. E) The phage DNA is incorporated by crossing over into any nonspecific site on the host cellʹs DNA.
C) The phage genome replicates along with the host genome.
A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur? A) The plants would develop some but not all of the symptoms of the TMV infection. B) The plants would develop symptoms typically produced by viroids. C) The plants would develop the typical symptoms of TMV infection. D) The plants would not show any disease symptoms. E) The plants would become infected, but the sap from these plants would be unable to infect other plants.
C) The plants would develop the typical symptoms of TMV infection.
When does exon shuffling occur? A) during splicing of DNA B) during mitotic recombination C) as an alternative splicing pattern in post-transcriptional processing D) as an alternative cleavage or modification post-translationally E) as the result of faulty DNA repair
C) as an alternative splicing pattern in post-transcriptional processing
To cause a human pandemic, the H5N1 avian flu virus would have to A) spread to primates such as chimpanzees. B) develop into a virus with a different host range. C) become capable of human-to-human transmission. D) arise independently in chickens in North and South America. E) become much more pathogenic.
C) become capable of human-to-human transmission.
In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of the bacteriophage? A) regulation via acetylation of histones B) positive control mechanisms rather than negative C) control of more than one gene in an operon D) reliance on transcription activators E) utilization of eukaryotic polymerases
C) control of more than one gene in an operon
A microarray known as a GeneChip, with most now known human protein coding sequences, has recently been developed to aid in the study of human cancer by first comparing two--three subsets of cancer subtypes. What kind of information might be gleaned from this GeneChip to aid in cancer prevention? A) information about whether or not a patient has this type of cancer prior to treatment. B) evidence that might suggest how best to treat a personʹs cancer with chemotherapy. C) data that could alert patients to what kind of cancer they were likely to acquire. D) information about which parent might have provided a patient with cancer-causing genes. E) information on cancer epidemiology in the U.S. or elsewhere.
C) data that could alert patients to what kind of cancer they were likely to acquire.
Which of the following characteristics, structures, or processes is common to both bacteria and viruses? A) metabolism B) ribosomes C) genetic material composed of nucleic acid D) cell division E) independent existence
C) genetic material composed of nucleic acid
Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this phenomenon? A) gene duplication B) RNA splicing C) exon shuffling D) histone modification E) random point mutations
C) exon shuffling
Which of the following terms describes bacteriophage DNA that has become integrated into the host cell chromosome? A) intemperate bacteriophages B) transposons C) prophages D) T-even phages E) plasmids
C) prophages
Bioinformatics includes all of the following except A) using computer programs to align DNA sequences. B) analyzing protein interactions in a species. C) using molecular biology to provide biological information to a system so that it gets expressed. D) development of computer-based tools for genome analysis. E) use of mathematical tools to make sense of biological systems.
C) using molecular biology to provide biological information to a system so that it gets expressed.
How is a physical map of the genome of an organism achieved? A) using recombination frequency B) using very high-powered microscopy C) using restriction enzyme cutting sites D) using sequencing of nucleotides E) using DNA fingerprinting via electrophoresis
C) using restriction enzyme cutting sites
Which of the following is characteristic of the lytic cycle? A) Many bacterial cells containing viral DNA are produced. B) Viral DNA is incorporated into the host genome. C) The viral genome replicates without destroying the host. D) A large number of phages is released at a time. E) The virus-host relationship usually lasts for generations.
D) A large number of phages is released at a time.
Which of the following is a major distinction between a transposon and a retrotransposon? A) A transposon always leaves a copy of itself at its original position and a retrotransposon does not. B) A retrotransposon always uses the copy-paste mechanism, while a transposon uses cut and paste mechanism. C) A transposon is related to a virus and a retrotransposon is not. D) A transposon moves via a DNA intermediate and a retrotransposon via an RNA intermediate. E) The positioning of a transposon copy is transient while that of a retrotransposon is permanent.
D) A transposon moves via a DNA intermediate and a retrotransposon via an RNA intermediate.
Why might the cricket genome have 11 times as many base pairs than that of Drosophila melanogaster? A) The two insect species evolved at very different geologic eras. B) Crickets have higher gene density. C) Drosophila are more complex organisms. D) Crickets must have more non-coding DNA. E) Crickets must make many more proteins.
D) Crickets must have more non-coding DNA.
Which treatment would you use to determine if the agent is a prion? A) I only B) II only C) III only D) IV only E) either I or IV
D) IV only
A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have A) T2 protein and T4 DNA. B) T2 protein and T2 DNA. C) a mixture of the DNA and proteins of both phages. D) T4 protein and T4 DNA. E) T4 protein and T2 DNA.
D) T4 protein and T4 DNA.
Emerging viruses arise by A) mutation of existing viruses. B) the spread of existing viruses to new host species. C) the spread of existing viruses more widely within their host species. D) all of the above E) none of the above
D) all of the above
How might identical and obviously duplicated gene sequences have gotten from one chromosome to another? A) by normal meiotic recombination B) by normal mitotic recombination between sister chromatids C) by transcription followed by recombination D) by chromosomal translocation E) by deletion followed by insertion
D) by chromosomal translocation
Which of the following most correctly describes a shotgun technique for sequencing a genome? A) genetic mapping followed immediately by sequencing B) physical mapping followed immediately by sequencing C) cloning large genome fragments into very large vectors such as YACs, followed by sequencing D) cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them E) cloning the whole genome directly, from one end to the other
D) cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them
Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of life? A) re-infection by a closely related herpesvirus of a different strain B) re-infection by the same herpesvirus strain C) co-infection with an unrelated virus that causes the same symptoms D) copies of the herpesvirus genome permanently maintained in host nuclei E) copies of the herpesvirus genome permanently maintained in host cell cytoplasm
D) copies of the herpesvirus genome permanently maintained in host nuclei
Viral genomes vary greatly in size and may include from four genes to several hundred genes. Which of the following viral features is most apt to correlate with the size of the genome? A) size of the viral capsomeres B) RNA versus DNA genome C) double versus single strand genomes D) size and shape of the capsid E) glycoproteins of the envelope
D) size and shape of the capsid
Fragments of DNA have been extracted from the remnants of extinct wooly mammoths, amplified, and sequenced. These can now be used to A) introduce into relatives, such as elephants, certain mammoth traits. B) clone live wooly mammoths. C) study the relationships among wooly mammoths and other wool-producers. D) understand the evolutionary relationships among members of related taxa. E) appreciate the reasons why mammoths went extinct
D) understand the evolutionary relationships among members of related taxa.
Which of the following series best reflects what we know about how the flu virus moves between species? A) An avian flu virus undergoes several mutations and rearrangements such that it is able to be transmitted to other birds and then to humans. B) The flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. C) A flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans. D) An influenza virus gains new sequences of DNA from another virus, such as a herpesvirus; this enables it to be transmitted to a human host. E) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates and is passed to a new species such as a bird, the virus mutates and can be transmitted to humans.
E) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates and is passed to a new species such as a bird, the virus mutates and can be transmitted to humans.
Which of the following has the largest genome and the fewest genes per million base pairs? A) Haemophilus influenzae (bacterium) B) Saccharomyces cerevisiae (yeast) C) Arabidopsis thaliana (plant) D) Drosophila melanogaster (fruit fly) E) Homo sapiens (human)
E) Homo sapiens (human)
Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host? A) It is able to spread to a large number of new hosts quickly because the new hosts have no immunological memory of them. B) The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts. C) A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas. D) Sporadic outbreaks will be followed almost immediately by a widespread pandemic. E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.
E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.
What is the most probable explanation for the continued presence of pseudogenes in a genome such as our own? A) They are genes that had a function at one time, but that have lost their function because they have been translocated to a new location. B) They are genes that have accumulated mutations to such a degree that they would code for different functional products if activated. C) They are duplicates or near duplicates of functional genes but cannot function because they would provide inappropriate dosage of protein products. D) They are genes with significant inverted sequences. E) They are genes that are not expressed, even though they have nearly identical sequences to expressed genes.
E) They are genes that are not expressed, even though they have nearly identical sequences to expressed genes.
Most molecular biologists think that viruses originated from fragments of cellular nucleic acid. Which of the following observations supports this theory? A) Viruses contain either DNA or RNA. B) Viruses are enclosed in protein capsids rather than plasma membranes. C) Viruses can reproduce only inside host cells. D) Viruses can infect both prokaryotic and eukaryotic cells. E) Viral genomes are usually more similar to the genome of the host cell than to the genomes of viruses that infect other cell types.
E) Viral genomes are usually more similar to the genome of the host cell than to the genomes of viruses that infect other cell types.
Although quite different in structure, plants and animals share some basic similarities in their development, such as A) the importance of cell and tissue movements. B) the importance of selective cell enlargement. C) the importance of homeobox-containing homeotic genes. D) a common evolutionary origin of the complete developmental program. E) a cascade of transcription factors that regulate gene expression on a finer and finer scale.
E) a cascade of transcription factors that regulate gene expression on a finer and finer scale.
Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this? A) exon shuffling B) intron activation C) pseudogene activation D) differential translation of mRNAs E) differential gene regulation over time
E) differential gene regulation over time
Multigene families are A) groups of enhancers that control transcription. B) usually clustered at the telomeres. C) equivalent to the operons of prokaryotes. D) sets of genes that are coordinately controlled. E) identical or similar genes that have evolved by gene duplication.
E) identical or similar genes that have evolved by gene duplication.
The biggest problem with the shotgun technique is its tendency to underestimate the size of the genome. Which of the following might best account for this? A) skipping some of the clones to be sequenced B) missing some of the overlapping regions of the clones C) counting some of the overlapping regions of the clones twice D) having some of the clones die during the experiment and therefore not be represented E) missing some duplicated sequences
E) missing some duplicated sequences
