bio 111 chapter 18-19

53) The product of the p53 gene _____. A) inhibits the cell cycle B) slows down the rate of DNA replication by interfering with the binding of DNA polymerase C) causes cells to reduce expression of genes involved in DNA repair D) allows cells to pass on mutations due to DNA damage

A) inhibits the cell cycle

38) Effective antiviral drugs are usually associated with which of the following properties? A) interference with viral replication B) prevention of the host from becoming infected C) removal of viral proteins D) removal of viral mRNAs

A) interference with viral replication

4) Viruses _____. A) manufacture their own ATP, proteins, and nucleic acids B) use the host cell to copy themselves and make viral proteins C) use the host cell to copy themselves and then viruses synthesize their own proteins D) metabolize food and produce their own ATP

B) use the host cell to copy themselves and make viral proteins

17) The trp repressor blocks transcription of the trp operon when the repressor _____. A) binds to the inducer B) binds to tryptophan C) is not bound to tryptophan D) is not bound to the operator

B) binds to tryptophan

35) At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. Many people were surprised that the number of protein-coding sequences was much smaller than they had expected. Which of the following could account for much of the DNA that is not coding for proteins? A) DNA that consists of histone coding sequences B) DNA that is translated directly without being transcribed C) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function D) non-protein-coding DNA that serves as binding sites for reverse transcriptase

A) DNA that consists of histone coding sequences

48) Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations? A) High mutation rate due to lack of proofreading of RNA genome replication errors. B) Transcription from the host cell RNA polymerase introduces numerous mutations. C) Capsid proteins from the host cell can replace the viral capsid. D) Viral RNA is translated by host cell ribosomes.

A) High mutation rate due to lack of proofreading of RNA genome replication errors.

28) In eukaryotes, general transcription factors _____ A) bind to other proteins or to the TATA box B) inhibit RNA polymerase binding to the promoter and begin transcribing C) usually lead to a high level of transcription even without additional specific transcription factors D) bind to sequences just after the start site of transcription

A) bind to other proteins or to the TATA box

12) What is the function of reverse transcriptase in retroviruses? A) It uses viral RNA as a template for DNA synthesis. B) It converts host cell RNA into viral DNA. C) It translates viral RNA into proteins. D) It uses viral RNA as a template for making complementary RNA strands.

A) It uses viral RNA as a template for DNA synthesis.

44) Will treating a viral infection with antibiotics affect the course of the infection? A) No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes. B) No; antibiotics do not kill viruses because viruses do not have DNA or RNA. C) Yes; antibiotics activate the immune system, and this decreases the severity of the infection. D) Yes; antibiotics can prevent viral entry into the cell by binding to host-receptor proteins.

A) No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes.

34) The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called _____. A) RNA interference B) RNA obstruction C) RNA blocking D) RNA disposal

A) RNA interference

16) According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon? A) The lac operon would be transcribed continuously. B) Only lacZ would be transcribed. C) Only lacY would be transcribed. D) Galactosidase permease would be produced, but would be incapable of transporting lactose.

A) The lac operon would be transcribed continuously.

22) If a viral host cell has a mutation that interferes with the addition of carbohydrates to proteins in the Golgi, which of the following could likely result? A) The viral envelope proteins would not be glycosylated and might not arrive at the host plasma membrane. B) The viral capsid proteins would not be glycosylated and might not arrive at the host plasma membrane. C) The viral core proteins would not be glycosylated and might not arrive at the host plasma membrane. D) The virus would be unable to reproduce within the host cell.

A) The viral envelope proteins would not be glycosylated and might not arrive at the host plasma membrane.

3) Which of the following supports the argument that viruses are nonliving? A) They are not cellular. B) Their DNA does not encode proteins. C) They have RNA rather than DNA. D) They do not evolve.

A) They are not cellular.

30) Which of the following is most likely to have a small protein called ubiquitin attached to it? A) a cyclin protein, that usually acts in G1, in a cell that is in G2 B) a cell surface protein that requires transport from the ER C) an mRNA leaving the nucleus to be translated D) an mRNA produced by an egg cell that will be retained until after fertilization

A) a cyclin protein, that usually acts in G1, in a cell that is in G2

37) Which of the following best describes siRNA? A) a double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA B) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns C) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor D) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits

A) a double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA

50) The protein of the bicoid gene in Drosophila determines the _____ of the embryo. A) anterior-posterior axis B) anterior-lateral axis C) posterior-dorsal axis D) posterior-ventral axis

A) anterior-posterior axis

37) A person is most likely to recover from a viral infection if the infected cells _____. A) can undergo normal cell division B) can carry on translation, at least for a few hours C) produce and release viral protein D) transcribe viral mRNA

A) can undergo normal cell division

57) A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which type(s) of cancer? A) colorectal only B) lung and breast C) lung only D) lung and prostate

A) colorectal only

5) A mutation that inactivates a regulatory gene of a repressible operon in an E. coli cell would result in _____. A) continuous transcription of the structural gene controlled by that regulator B) complete inhibition of transcription of the structural gene controlled by that regulator C) irreversible binding of the repressor to the operator D) continuous translation of the mRNA because of alteration of its structure

A) continuous transcription of the structural gene controlled by that regulator

40) The fact that plants can be cloned from somatic cells demonstrates that _____. A) differentiated cells retain all the genes of the zygote B) genes are lost during differentiation C) the differentiated state is normally very unstable D) differentiation does not occur in plants

A) differentiated cells retain all the genes of the zygote

3) Which of the following, when taken up by a cell, binds to a repressor so that the repressor no longer binds to the operator? A) inducer B) promoter C) repressor D) corepressor

A) inducer

4) Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation? A) inducer B) promoter C) transcription factor D) cAMP

A) inducer

27) Which of the following could use reverse transcriptase to transcribe its genome? A) ssRNA B) dsRNA C) ssDNA D) dsDNA

A) ssRNA

46) A population of viruses with similar characteristics is called a _____. A) strain B) species C) type D) genome

A) strain

55) BRCA1 and BRCA2 are considered to be tumor-suppressor genes because _____. A) their normal products participate in repair of DNA damage B) the mutant forms of either one of these prevent breast cancer C) the normal genes make estrogen receptors D) they block penetration of breast cells by chemical carcinogens

A) their normal products participate in repair of DNA damage

35) The difference between vertical and horizontal transmission of plant viruses is that vertical transmission is _____. A) transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant B) 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) 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) 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) transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant

29) Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell? A) herpes B) AIDS C) smallpox D) influenza

B) AIDS

43) What is difference between an epidemic and a pandemic? A) An epidemic is a disease; a pandemic is a treatment. B) An epidemic is restricted to a local region; a pandemic is global. C) An epidemic has low mortality; a pandemic has higher mortality. D) An epidemic is caused by a bacterial infection; a pandemic is caused by a viral infection.

B) An epidemic is restricted to a local region; a pandemic is global.

49) When the Bicoid protein is expressed in Drosophila, the embryo is still syncytial (divisions between cells are not yet fully developed). This information helps to explain which observation by Nüsslein-Volhard and Wieschaus? A) mRNA from the egg is translated into the Bicoid protein. B) Bicoid protein diffuses throughout the embryo in a concentration gradient. C) Bicoid protein serves as a transcription regulator. D) Bicoid protein determines the dorsoventral axis of the embryo.

B) Bicoid protein diffuses throughout the embryo in a concentration gradient.

30) 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 proofreading. C) RNA viruses can incorporate a variety of nonstandard bases. D) RNA viruses are more sensitive to mutagens.

B) Replication of their genomes does not involve proofreading.

39) When she finds that the introduced strand separates into single-stranded RNAs, what other evidence of this single-stranded RNA piece's activity can she find? A) She can measure the degradation rate of the remaining single strand. B) The rate of accumulation of the polypeptide encoded by the target mRNA is reduced. C) The amount of miRNA is multiplied by its replication. D) The cell's translation ability is entirely shut down.

B) The rate of accumulation of the polypeptide encoded by the target mRNA is reduced.

17) Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence, and then a single long protein-coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short period use of the radioactive amino acids result in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment? A) Host cell ribosomes only translate the viral code into short polypeptides. B) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. C) The RNA is translated into short polypeptides, which are subsequently assembled into large ones. D) The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus.

B) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones.

23) HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings? A) HIV can be transmitted more easily from person to person than the flu virus B) The flu virus can be transmitted more easily from person to person than HIV C) This property of HIV makes it more likely to be a pandemic than the flu virus D) Disinfecting surfaces is more important to reduce the spread of HIV than the flu

B) The flu virus can be transmitted more easily from person to person than HIV

26) Which of the following mechanisms is (are) used to coordinate the expression of multiple, related genes in eukaryotic cells? A) Environmental signals enter the cell and bind directly to promoters. B) The genes share a single common enhancer, which allows appropriate activators to turn on their transcription at the same time. C) The genes are organized into a large operon, allowing them to be coordinately controlled as a single unit. D) A single repressor is able to turn off several related genes.

B) The genes share a single common enhancer, which allows appropriate activators to turn on their transcription at the same time.

24) Viruses use the host's machinery to make copies of themselves. However, some human viruses require a type of replication that humans do not normally have. For example, humans normally do not have the ability to convert RNA into DNA. How can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires? A) The virus causes mutations in the human cells, resulting in the formation of new enzymes that are capable of performing these roles. B) The viral genome codes for specialized enzymes not in the host. C) The virus infects only those cells and species that can perform all the replication roles necessary. D) Viruses can stay in a quiescent state until the host cell evolves this ability.

B) The viral genome codes for specialized enzymes not in the host.

34) 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 have genomes composed of RNA, whereas viroids have genomes composed of DNA. D) Viruses cannot pass through plasmodesmata, whereas viroids can.

B) Viruses have capsids composed of protein, whereas viroids have no capsids.

10) In positive control of several sugar-metabolism-related operons, the catabolite activator protein (CAP) binds to DNA to stimulate transcription. What causes an increase in CAP activity in stimulating transcription? A) an increase in glucose and an increase in cAMP B) a decrease in glucose and an increase in cAMP C) an increase in glucose and a decrease in cAMP D) a decrease in glucose and a decrease in the repressor

B) a decrease in glucose and an increase in cAMP

43) If a Drosophila female has a homozygous mutation for a maternal effect gene, _____. A) she will not develop past the early embryonic stage B) all of her offspring will show the mutant phenotype, regardless of their genotype C) only her male offspring will show the mutant phenotype D) only her female offspring will show the mutant phenotype

B) all of her offspring will show the mutant phenotype, regardless of their genotype

21) Which of the following viruses would most likely have reverse transcriptase? A) an RNA-based lytic virus B) an RNA-based lysogenic virus C) a DNA-based lytic virus D) a DNA-based lysogenic virus

B) an RNA-based lysogenic virus

38) Some time later, she finds that the introduced strand separates into single-stranded RNAs, one of which is degraded. What does this enable the remaining strand to do? A) attach to histones in the chromatin B) bind to complementary regions of target mRNAs C) activate other siRNAs in the cell D) bind to noncomplementary RNA sequences

B) bind to complementary regions of target mRNAs

33) Viral infections in plants _____. A) can be controlled with antibiotics B) can spread within a plant via plasmodesmata C) have little effect on plant growth D) are not spread by animals

B) can spread within a plant via plasmodesmata

31) In one set of experiments she succeeded in increasing acetlylation of histone tails. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin condensation C) decreased binding of transcription factors D) inactivation of the selected genes

B) decreased chromatin condensation

31) 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. We expect that the plants would _____. A) develop some but not all of the symptoms of the TMV infection B) develop the typical symptoms of TMV infection C) not show any disease symptoms D) become infected, but the sap from these plants would be unable to infect other plants

B) develop the typical symptoms of TMV infection

47) In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated? A) genes coding for enzymes that act in the colon B) genes involved in control of the cell cycle C) genes that are especially susceptible to mutation D) genes of the bacteria, which are abundant in the colon

B) genes involved in control of the cell cycle

58) In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated? A) genes coding for enzymes that act in the colon B) genes involved in control of the cell cycle C) genes that are especially susceptible to mutation D) genes of the bacteria, which are abundant in the colon

B) genes involved in control of the cell cycle

32) Which of the following can be effective in preventing the onset of viral infection in humans? A) taking vitamins B) getting vaccinated C) taking antibiotics D) taking drugs that inhibit transcription

B) getting vaccinated

28) To make a vaccine against mumps, measles, or rabies, which type of viruses would be useful? A) dsDNA viruses B) negative-sense ssRNA viruses C) positive-sense ssRNA viruses D) dsRNA viruses

B) negative-sense ssRNA viruses

36) Among the newly discovered small noncoding RNAs, one type reestablishes methylation patterns during gamete formation and blocks expression of some transposons. These are known as _____. A) miRNA B) piRNA C) snRNA D) siRNA

B) piRNA

26) A virus consisting of a single strand of RNA, which is transcribed into complementary DNA, is a _____. A) protease B) retrovirus C) RNA replicase virus D) nonenveloped virus

B) retrovirus

7) Transcription of structural genes in an inducible operon _____. A) occurs continuously in the cell B) starts when the pathway's substrate is present C) starts when the pathway's product is present D) stops when the pathway's product is present

B) starts when the pathway's substrate is present

9) Which of the following is characteristic of the lytic cycle? A) Viral DNA is incorporated into the host genome. B) The viral genome replicates without destroying the host. C) A large number of phages are released at a time. D) The virus—host relationship usually lasts for generations.

C) A large number of phages are released at a time.

46) The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur? A) The embryo would grow extra wings and legs. B) The embryo would probably show no anterior development and die. C) Anterior structures would form in both ends of the embryo. D) The embryo would develop normally.

C) Anterior structures would form in both ends of the embryo.

5) 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.

C) Enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane.

45) Why do scientists consider HIV to be an emerging virus? A) HIV infected humans long before the 1980s, but it has now mutated to a more deadly form. B) HIV mutates rapidly making the virus very different from HIV in the early 1980s. C) HIV suddenly became apparent and widespread in the 1980s. D) HIV is now starting to cause diseases other than AIDS, such as rare types of cancers and pneumonias.

C) HIV suddenly became apparent and widespread in the 1980s.

11) There is a mutation in the repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant? A) It cannot bind to the operator. B) It cannot make a functional repressor. C) It cannot bind to the inducer. D) It makes a repressor that binds CAP.

C) It cannot bind to the inducer.

8) For a repressible operon to be transcribed, which of the following must occur? A) A corepressor must be present. B) RNA polymerase and the active repressor must be present. C) RNA polymerase must bind to the promoter, and the repressor must be inactive. D) RNA polymerase must not occupy the promoter, and the repressor must be inactive.

C) RNA polymerase must bind to the promoter, and the repressor must be inactive.

49) In 2009, a flu pandemic was believed to have originated when viral transmission occurred from pig to human, thereby earning the designation, "swine flu." Although pigs are thought to have been the breeding ground for the 2009 virus, sequences from bird, pig, and human viruses were all found within this newly identified virus. What is the most likely explanation of why this virus contained sequences from bird, pig, and human viruses? A) The virus was descended from a common ancestor of bird, pig, and human flu viruses. B) The infected individuals happened to be infected with all three virus types. C) Related viruses can undergo genetic recombination if the RNA genomes mix and match during viral assembly. D) The human was likely infected with various bacterial strains that contained all three RNA viruses.

C) Related viruses can undergo genetic recombination if the RNA genomes mix and match during viral assembly.

10) 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) The phage DNA is copied and exits the cell as a phage.

C) The phage genome replicates along with the host genome.

20) Imagine that you've isolated a yeast mutant that contains histones resistant to acetylation. What phenotype do you predict for this mutant? A) The mutant will grow rapidly. B) The mutant will require galactose for growth. C) The mutant will show low levels of gene expression. D) The mutant will show high levels of gene expression.

C) The mutant will show low levels of gene expression.

51) Which of the following types of mutation would convert a proto-oncogene into an oncogene? A) a mutation that blocks transcription of the proto-oncogene B) a mutation that creates an unstable proto-oncogene mRNA C) a mutation that greatly increases the amount of the proto-oncogene protein D) a deletion of most of the proto-oncogene coding sequence

C) a mutation that greatly increases the amount of the proto-oncogene protein

9) Altering patterns of gene expression in prokaryotes would most likely serve an organism's survival by _____. A) organizing gene expression, so that genes are expressed in a given order B) allowing each gene to be expressed an equal number of times C) allowing an organism to adjust to changes in environmental conditions D) allowing environmental changes to alter a prokaryote's genome

C) allowing an organism to adjust to changes in environmental conditions

24) Not long ago, it was believed that a count of the number of protein-coding genes would provide a count of the number of proteins produced in any given eukaryotic species. This is incorrect, largely due to the discovery of widespread _____. A) chromatin condensation control B) transcriptional control C) alternative splicing D) translational control

C) alternative splicing

21) The primary difference between enhancers and promoter-proximal elements is that enhancers _____. A) are transcription factors; promoter-proximal elements are DNA sequences B) enhance transcription; promoter-proximal elements inhibit transcription C) are at considerable distances from the promoter; promoter-proximal elements are close to the promoter D) are DNA sequences; promoter-proximal elements are proteins

C) are at considerable distances from the promoter; promoter-proximal elements are close to the promoter

25) The first class of drugs developed to treat AIDS, such as AZT, were known as reverse transcriptase inhibitors. They worked because they _____. A) targeted and destroyed the viral genome before it could be reverse transcribed into DNA B) bonded to the dsDNA genome of the virus in such a way that it could not separate for replication to occur C) bonded to the viral reverse transcriptase enzyme, thus preventing the virus from making a DNA copy of its RNA genome D) prevented host cells from producing the enzymes used by the virus to replicate its genome

C) bonded to the viral reverse transcriptase enzyme, thus preventing the virus from making a DNA copy of its RNA genome

15) What would occur if the repressor of an inducible operon were mutated so that it could not bind the operator? A) irreversible binding of the repressor to the promoter B) reduced transcription of the operon's genes C) continuous transcription of the operon's genes D) overproduction of catabolite activator protein (CAP)

C) continuous transcription of the operon's genes

8) 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 a 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

C) control of more than one gene in an operon

7) Which of the following accounts for someone who has had regular herpesvirus-mediated cold sore or genital sore flare-ups? A) re-infection by a closely related herpesvirus of a different strain B) re-infection by the same herpesvirus strain C) copies of the herpesvirus genome permanently maintained in host nuclei D) copies of the herpesvirus genome permanently maintained in host cell cytoplasm

C) copies of the herpesvirus genome permanently maintained in host nuclei

45) Which of the following are maternal effect genes that control the orientation of the egg and thus the Drosophila embryo? A) homeotic genes B) segmentation genes C) egg-polarity genes D) morphogens

C) egg-polarity genes

54) Tumor-suppressor genes _____. A) are frequently overexpressed in cancerous cells B) are cancer-causing genes introduced into cells by viruses C) encode proteins that help prevent uncontrolled cell growth D) often encode proteins that stimulate the cell cycle

C) encode proteins that help prevent uncontrolled cell growth

27) DNA methylation and histone acetylation are examples of _____. A) genetic mutation B) chromosomal rearrangements C) epigenetic phenomena D) translocation

C) epigenetic phenomena

44) Mutations in which of the following genes lead to transformations in the identity of entire body parts? A) segmentation genes B) egg-polarity genes C) homeotic genes D) inducers

C) homeotic genes

48) A cell is considered to be differentiated when it _____. A) replicates by the process of mitosis B) loses connections to the surrounding cells C) produces proteins specific to a particular cell type D) appears to be different from the surrounding cells

C) produces proteins specific to a particular cell type

22) The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different _____. A) genes B) regulatory sequences C) sets of regulatory proteins D) promoters

C) sets of regulatory proteins

52) Proto-oncogenes _____. A) normally suppress tumor growth B) are produced by somatic mutations induced by carcinogenic substances C) stimulate normal cell growth and division D) are underexpressed in cancer cells

C) stimulate normal cell growth and division

6) The lactose operon is likely to be transcribed when _____. A) there is more glucose in the cell than lactose B) there is glucose but no lactose in the cell C) the cyclic AMP and lactose levels are both high within the cell D) the cAMP level is high and the lactose level is low

C) the cyclic AMP and lactose levels are both high within the cell

20) The virus genome and viral proteins are assembled into virions (virus particles) during _____. A) the lytic cycle and the lysogenic cycle in all known host organisms B) the lysogenic cycle only C) the lytic cycle only D) the lytic cycle in all host organisms but the lysogenic cycle only in bacteria

C) the lytic cycle only

39) Which of the following best reflects what we know about how the flu virus moves between species? A) The flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. B) A flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans. C) 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. D) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans.

D) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans.

12) If she moves the promoter for the lac operon to the region between the beta galactosidase (lacZ) gene and the permease (lacY) gene, which of the following would be likely? A) The three structural genes will be expressed normally. B) RNA polymerase will no longer transcribe permease. C) The operon will still transcribe the lacZ and lacY genes, but the mRNA will not be translated. D) Beta galactosidase will not be produced.

D) Beta galactosidase will not be produced.

19) CAP is said to be responsible for positive regulation of the lac operon because _____. A) CAP binds cAMP B) CAP binds to the CAP-binding site C) CAP prevents binding of the repressor to the operator D) CAP bound to the CAP-binding site increases the frequency of transcription initiation

D) CAP bound to the CAP-binding site increases the frequency of transcription initiation

13) If she moves the operator to the far end of the operon, past the transacetylase (lacA) gene, which of the following would likely occur when the cell is exposed to lactose? A) The inducer will no longer bind to the repressor. B) The repressor will no longer bind to the operator. C) The operon will never be transcribed. D) The structural genes will be transcribed continuously.

D) The structural genes will be transcribed continuously.

47) Evidence suggests that factors which contribute towards the virulence of E. coli strain O157:H7, a bacterial strain reported to cause several food poisoning deaths, are caused by genes from a virus that infects bacteria. Considering this evidence, which statement most likely explains how the O157:H7 population acquired the genetic variation that distinguishes the strain from harmless E. coli strains, such as those that reside in our intestines? A) The virus entered the bacterial cell and incorporated its DNA into the bacterial genome, allowing the bacteria's cellular machinery to create new viruses. B) Viral envelope proteins bind to receptors on the bacterial membrane, allowing the viral genetic material to enter the bacterium and become translated into proteins. C) The virus entered the cell and acquired specific genes from the bacteria to increase the virulence of the virus. D) The virus infected the bacterium, and allowed the bacterial population to replicate with a copy of the phage genome in each new bacterium.

D) The virus infected the bacterium, and allowed the bacterial population to replicate with a copy of the phage genome in each new bacterium.

29) Steroid hormones produce their effects in cells by _____. A) activating key enzymes in metabolic pathways B) activating translation of certain mRNAs C) promoting the degradation of specific mRNAs D) binding to intracellular receptors and promoting transcription of specific genes

D) binding to intracellular receptors and promoting transcription of specific genes

25) One way to detect alternative splicing of transcripts from a given gene is to _____. A) compare the DNA sequence of the given gene to that of a similar gene in a related organism B) measure the relative rates of transcription of the given gene compared to that of a gene known to be constitutively spliced C) compare the sequences of different primary transcripts made from the given gene D) compare the sequences of different mRNAs made from the given gene

D) compare the sequences of different mRNAs made from the given gene

33) Which method is utilized by eukaryotes to control their gene expression that is NOT used in bacteria? A) control of chromatin remodeling B) control of RNA splicing C) transcriptional control D) control of both RNA splicing and chromatin remodeling

D) control of both RNA splicing and chromatin remodeling

1) Which of the following is a protein produced by a regulatory gene? A) operon B) inducer C) promoter D) repressor

D) repressor

11) Which viruses have single-stranded RNA that acts as a template for DNA synthesis? A) proviruses B) viroids C) bacteriophages D) retroviruses

D) retroviruses

2) A lack of which molecule would result in a cell's inability to "turn off" genes? A) operon B) inducer C) promoter D) corepressor

D) corepressor

56) Forms of the Ras protein found in tumors usually cause which of the following? A) DNA replication to stop B) cell-to-cell adhesion to be nonfunctional C) cell division to cease D) excessive cell division

D) excessive cell division

32) One of her colleagues suggested she try increased methylation of C nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see? A) decreased chromatin condensation B) activation of histone tails for enzymatic function C) higher levels of transcription of certain genes D) inactivation of the selected genes

D) inactivation of the selected genes

14) If she moves the repressor gene (lacI), along with its promoter, to a position at some several thousand base pairs away from its normal position, we would expect the _____. A) repressor will no longer bind to the operator B) repressor will no longer bind to the inducer C) lac operon will be expressed continuously D) lac operon will function normally

D) lac operon will function normally

36) What are prions? A) mobile segments of DNA B) tiny circular molecules of RNA that can infect plants C) viral DNA that attaches itself to the host genome and causes disease D) misfolded versions of normal protein that can cause disease

D) misfolded versions of normal protein that can cause disease

41) Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development? A) morphogenesis B) determination C) differentiation D) pattern formation

D) pattern formation

18) Extracellular glucose inhibits transcription of the lac operon by _____. A) strengthening the binding of the repressor to the operator B) weakening the binding of the repressor to the operator C) inhibiting RNA polymerase from opening the strands of DNA to initiate transcription D) reducing the levels of intracellular cAMP

D) reducing the levels of intracellular cAMP

42) The product of the bicoid gene in Drosophila provides essential information about _____. A) the dorsal-ventral axis B) the left-right axis C) segmentation D) the anterior-posterior axis

D) the anterior-posterior axis

6) The host range of a virus is determined by _____. A) the enzymes carried by the virus B) whether its nucleic acid is DNA or RNA C) the proteins in the host's cytoplasm D) the proteins on its surface and that of the host

D) the proteins on its surface and that of the host

23) Gene expression is often assayed by measuring the level of mRNA produced from a gene. If one is interested in knowing the amount of a final active gene product, a potential problem of this method is that it ignores the possibility of _____. A) chromatin condensation control B) transcriptional control C) alternative splicing D) translational control

D) translational control