AP Biology Chapters 18,19,20

1) What does the operon model attempt to explain? A) the coordinated control of gene expression in bacteria B) bacterial resistance to antibiotics C) how genes move between homologous regions of DNA D) the mechanism of viral attachment to a host cell E) horizontal transmission of plant viruses

A

60) One possible use of transgenic plants is in the production of human proteins, such as vaccines. Which of the following is a possible hindrance that must be overcome? A) prevention of transmission of plant allergens to the vaccine recipients B) prevention of vaccine-containing plants being consumed by insects C) use of plant cells to translate non-plant derived mRNA D) inability of the human digestive system to accept plant-derived protein E) the need to cook all such plants before consuming them

A) prevention of transmission of plant allergens to the vaccine recipients

9) Bacteria that do not take up any plasmids would grow on which media? A) the nutrient broth only B) the nutrient broth and the tetracycline broth C) the nutrient broth and the ampicillin broth D) the tetracycline broth and the ampicillin broth E) all four broths

A) the nutrient broth only

40) Transcription factors in eukaryotes usually have DNA binding domains as well as other domains also specific for binding. In general, which of the following would you expect many of them to be able to bind? A) repressors B) ATP C) protein-based hormones D) other transcription factors E) tRNA

A

13) Allolactose induces the synthesis of the enzyme lactase. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell? A) The repressor protein attaches to the regulator. B) Allolactose binds to the repressor protein. C) Allolactose binds to the regulator gene. D) The repressor protein and allolactose bind to RNA polymerase. E) RNA polymerase attaches to the regulator.

B

22) If you were to observe the activity of methylated DNA, you would expect it to76 A) be replicating nearly continuously. B) be unwinding in preparation for protein synthesis. C) have turned off or slowed down the process of transcription. D) be very actively transcribed and translated. E) induce protein synthesis by not allowing repressors to bind to it.

C

45) Which of the following problems with animal cloning might result in premature death of the clones? A) use of pluripotent instead of totipotent stem cells B) use of nuclear DNA as well as mtDNA C) abnormal regulation due to variant methylation D) the indefinite replication of totipotent stem cells E) abnormal immune function due to bone marrow dysfunction

C) abnormal regulation due to variant methylation

11) How does active CAP induce expression of the genes of the lactose operon? A) It terminates production of repressor molecules. B) It degrades the substrate allolactose. C) It stimulates splicing of the encoded genes. D) It stimulates the binding of RNA polymerase to the promoter. E) It binds steroid hormones and controls translation

D

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) mutation of existing viruses, the spread of existing viruses to new host species, and the spread of existing viruses more widely within their host species. E) none of these.

D

52) Gene therapy A) has proven to be beneficial to HIV patients. B) involves replacement of a defective allele in sex cells. C) cannot be used to correct genetic disorders. D) had apparent success in treating disorders involving bone marrow cells. E) is a widely accepted procedure.

D) had apparent success in treating disorders involving bone marrow cells.

12) Why are yeast cells frequently used as hosts for cloning? A) they easily form colonies B) they can remove exons from mRNA. C) they do not have plasmids. D) they are eukaryotic cells E) only yeast cells allow the gene to be cloned

D) they are eukaryotic cells

3) What is the enzymatic function of restriction enzymes? A) to add new nucleotides to the growing strand of DNA B) to join nucleotides during replication C) to join nucleotides during transcription D) to cleave nucleic acids at specific sites E) to repair breaks in sugar-phosphate backbones

D) to cleave nucleic acids at specific sites

25) Which of the following is used to make complementary DNA (cDNA) from RNA? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase

E) reverse transcriptase

8) Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow in A) the nutrient broth only. B) the nutrient broth and the tetracycline broth only. C) the nutrient broth, the ampicillin broth, and the tetracycline broth. D) all four types of broth. E) the ampicillin broth and the nutrient broth.

E) the ampicillin broth and the nutrient broth.

21) Which of the following mechanisms is (are) used to coordinately control the expression of multiple, related genes in eukaryotic cells? A) organization of the genes into clusters, with local chromatin structures influencing the expression of all the genes at once B) each of the genes sharing a common control element, allowing several activators to turn on their transcription, regardless of their location in the genome C) organizing the genes into large operons, allowing them to be transcribed as a single unit D) a single repressor able to turn off several related genes E) environmental signals that enter the cell and bind directly to their promoters

A

26) In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of A) transcription. B) translation. C) mRNA stability. D) mRNA splicing. E) protein stability.

A

30) Eukaryotic cells can control gene expression by which of the following mechanisms? A) histone acetylation of nucleosomes B) DNA acetylation C) RNA induced modification of chromatin structure D) repression of operons E) induction of operators in the promoter

A

37) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. In one set of experiments she succeeded in decreasing methylation of histone tails. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected gene

A

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

A

44) 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 targeting. E) RNA disposal.

A

8) A mutation that inactivates the 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) inactivation of RNA polymerase by alteration of its active site. E) continuous translation of the mRNA because of alteration of its structure.

A

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

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

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

16) Which of the following best describes the complete sequence of steps occurring during every cycle of PCR? 1. The primers hybridize to the target DNA. 2. The mixture is heated to a high temperature to denature the double stranded target DNA. 3. Fresh DNA polymerase is added. 4. DNA polymerase extends the primers to make a copy of the target DNA. A) 2, 1, 4 B) 1, 3, 2, 4 C) 3, 4, 1, 2 D) 3, 4, 2 E) 2, 3, 4

A) 2, 1, 4

19) The first cell whose entire genome was sequenced was which of the following? A) H. influenzae in 1995 B) H. sapiens in 2001 C) rice in 1955 D) tobacco mosaic virus E) HIV in 1998

A) H. influenzae in 1995

55) Scientists developed a set of guidelines to address the safety of DNA technology. Which of the following is one of the adopted safety measures? A) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory. B) Genetically modified organisms are not allowed to be part of our food supply. C) Transgenic plants are engineered so that the plant genes cannot hybridize. D) Experiments involving HIV or other potentially dangerous viruses have been banned. E) Recombinant plasmids cannot be replicated.

A) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory.

37) Which was developed by a British researcher and causes DNA sequences to be transferred to a membrane and identified with a probe? A) Southern blotting B) Northern blotting C) Western blotting D) Eastern blotting E) RT-PCR

A) Southern blotting

48) A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following is a likely finding? A) The cells from the two sources exhibit different patterns of DNA methylation. B) Adult stem cells have more DNA nucleotides than their counterparts. C) The two kinds of cells have virtually identical gene expression patterns in microarrays. D) The non-stem cells have fewer repressed genes. E) The non-stem cells have lost the promoters for more genes.

A) The cells from the two sources exhibit different patterns of DNA methylation.

4) How does a bacterial cell protect its own DNA from restriction enzymes? A) adding methyl groups to adenines and cytosines B) using DNA ligase to seal the bacterial DNA into a closed circle C) adding histones to protect the double-stranded DNA D) forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching E) reinforcing the bacterial DNA structure with covalent phosphodiester bonds

A) adding methyl groups to adenines and cytosines

30) Which of the following modifications is least likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? A) altering the nucleotide sequence of the DNA fragment B) methylating the cytosine bases within the DNA fragment C) increasing the length of the DNA fragment D) decreasing the length of the DNA fragment E) neutralizing the negative charges within the DNA fragment

A) altering the nucleotide sequence of the DNA fragment

13) The DNA fragments making up a genomic library are generally contained in A) recombinant plasmids of bacteria. B) recombinant viral RNA. C) individual wells. D) DNA-RNA hybrids E) radioactive eukaryotic cells

A) recombinant plasmids of bacteria.

41) A researcher has used in vitro mutagenesis to mutate a cloned gene and then has reinserted this into a cell. In order to have the mutated sequence disable the function of the gene, what must then occur? A) recombination resulting in replacement of the wild type with the mutated gene B) use of a microarray to verify continued expression of the original gene C) replication of the cloned gene using a bacterial plasmid D) transcription of the cloned gene using a BAC E) attachment of the mutated gene to an existing mRNA to be translated

A) recombination resulting in replacement of the wild type with the mutated gene

32) RFLP analysis can be used to distinguish between alleles based on differences in which of the following? A) restriction enzyme recognition sites between the alleles B) the amount of DNA amplified from the alleles during PCR C) the ability of the alleles to be replicated in bacterial cells D) the proteins expressed from the alleles

A) restriction enzyme recognition sites between the alleles

26) Which of the following cuts DNA molecules at specific locations? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase

A) restriction enzymes

31) DNA fragments from a gel are transferred to a nitrocellulose paper during the procedure called Southern blotting. What is the purpose of transferring the DNA from a gel to a nitrocellulose paper? A) to attach the DNA fragments to a permanent substrate B) to separate the two complementary DNA strands C) to transfer only the DNA that is of interest D) to prepare the DNA for digestion with restriction enzymes E) to separate out the PCRs

A) to attach the DNA fragments to a permanent substrate

10) Transcription of the 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. E) does not result in the production of enzymes.

B

15) In response to chemical signals, prokaryotes can do which of the following? A) turn off translation of their mRNA B) alter the level of production of various enzymes C) increase the number and responsiveness of their ribosomes D) inactivate their mRNA molecules E) alter the sequence of amino acids in certain proteins

B

2) The role of a metabolite that controls a repressible operon is to A) bind to the promoter region and decrease the affinity of RNA polymerase for the promoter. B) bind to the operator region and block the attachment of RNA polymerase to the promoter. C) increase the production of inactive repressor proteins. D) bind to the repressor protein and inactivate it. E) bind to the repressor protein and activate it.

B

31) In eukaryotes, general transcription factors A) are required for the expression of specific protein-encoding genes. B) bind to other proteins or to a sequence element within the promoter called the TATA box. C) inhibit RNA polymerase binding to the promoter and begin transcribing. D) usually lead to a high level of transcription even without additional specific transcription factors. E) bind to sequences just after the start site of transcription.

B

33) The segment of DNA shown in Figure 20.2 has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?

B

36) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. In one set of experiments using this procedure in Drosophila, she was readily successful in increasing phosphorylation of amino acids adjacent to methylated amino acids in histone tails. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected genes

B

42) Which of the following experimental procedures is most likely to hasten mRNA degradation in a eukaryotic cell? A) enzymatic shortening of the poly(A) tail B) removal of the 5' cap C) methylation of C nucleotides D) memethylation of histones E) removal of one or more exons

B

7) When this is taken up by the cell, it binds to the repressor so that the repressor no longer binds to the operator: A) operon B) inducer C) promoter D) repressor E) corepressor

B

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 viral replication C) prevention of the host from becoming infected D) removal of viral proteins E) removal of viral mRNAs

B

If scientists are trying to use what they know about HSV to devise a means of protecting other people from being infected, which of the following would have the best chance of lowering the number of new cases of infection? A) vaccination of all persons with preexisting cases B) interference with new viral replication in preexisting cases C) treatment of the HSV lesions to shorten the breakout D) medication that destroys surface HSV before it gets to neurons E) education about avoiding sources of infection

B

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

Which of the following describes plant virus infections? A) They can be controlled by the use of antibiotics. B) They are spread via the plasmodesmata. C) They have little effect on plant growth. D) They are seldom spread by insects. E) They can never be passed vertically.

B

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

What is the function of reverse transcriptase in retroviruses? A) It hydrolyzes the host cell's 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

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) applying antiseptics E) taking nucleoside analogs that inhibit transcription

B

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, whereas 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, whereas viroids can.

B

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 replicate faster. D) RNA viruses can incorporate a variety of nonstandard bases. E) RNA viruses are more sensitive to mutagens.

B

Use Figure 20.3 to answer the following questions. The DNA profiles below represent four different individuals. 49) Which of the following statements is consistent with the results? A) B is the child of A and C. B) C is the child of A and B. C) D is the child of B and C. D) A is the child of B and C. E) A is the child of C and D.

B) C is the child of A and B.

46) Reproductive cloning of human embryos is generally considered unethical. However, on the subject of therapeutic cloning there is a wider divergence of opinion. Which of the following is a likely explanation? A) Use of adult stem cells is likely to produce more cell types than use of embryonic stem cells. B) Cloning to produce embryonic stem cells may lead to great medical benefits for many. C) Cloning to produce stem cells relies on a different initial procedure than reproductive cloning. D) A clone that lives until the blastocyst stage does not yet have human DNA. E) No embryos would be destroyed in the process of therapeutic cloning.

B) Cloning to produce embryonic stem cells may lead to great medical benefits for many.

50) Which of the following statements is most likely true? A) D is the child of A and C. B) D is the child of A and B. C) D is the child of B and C. D) A is the child of C and D. E) B is the child of A and C.

B) D is the child of A and B.

47) Which of the following is true of embryonic stem cells but not of adult stem cells? A) They can differentiate into many cell types. B) They make up the majority of cells of the tissue from which they are derived. C) They can continue to replicate for an indefinite period. D) They can provide enormous amounts of information about the process of gene regulation. E) One aim of using them is to provide cells for repair of diseased tissue.

B) They make up the majority of cells of the tissue from which they are derived.

21) To introduce a particular piece of DNA into an animal cell, such as that of a mouse, you would find more probable success with which of the following methods? A) the shotgun approach B) electroporation followed by recombination C) introducing a plasmid into the cell D) infecting the mouse cell with a Ti plasmid E) transcription and translation

B) electroporation followed by recombination

23) Which of the following produces multiple identical copies of a gene for basic research or for large-scale production of a gene product? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase

B) gene cloning

54) Genetically engineered plants A) are more difficult to engineer than animals. B) include a transgenic rice plant that can help prevent vitamin A deficiency. C) are being rapidly developed, but traditional plant breeding programs are still the only method used to develop new plants. D) are able to fix nitrogen themselves. E) are banned throughout the world.

B) include a transgenic rice plant that can help prevent vitamin A deficiency.

35) Dideoxyribonucleotide chain-termination is a method of A) cloning DNA. B) sequencing DNA.

B) sequencing DNA.

40) RNAi methodology uses double-stranded pieces of RNA to trigger a breakdown or blocking of mRNA. For which of the following might it more possibly be useful? A) to raise the rate of production of a needed digestive enzyme B) to decrease the production from a harmful gain-of-function mutated gene C) to destroy an unwanted allele in a homozygous individual D) to form a knockout organism that will not pass the deleted sequence to its progeny E) to raise the concentration of a desired protein

B) to decrease the production from a harmful gain-of-function mutated gene

12) For a repressible operon to be transcribed, which of the following must occur?74 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 cannot be present, and the repressor must be inactive. E) RNA polymerase must not occupy the promoter, and the repressor must be inactive.

C

14) Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways? 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 the organism to adjust to changes in environmental conditions D) allowing young organisms to respond differently from more mature organisms E) allowing environmental changes to alter the prokaryote's genom

C

29) During DNA replication, A) all methylation of the DNA is lost at the first round of replication. B) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are therefore left uncopied. C) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication. D) methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template. E) methylated DNA is copied in the cytoplasm, and unmethylated DNA in the nucleus.

C

32) This binds to a site in the DNA far from the promoter to stimulate transcription: A) enhancer B) promoter C) activator D) repressor E) terminator

C

39) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. She tried decreasing the amount of methylation enzymes in the embryonic stem cells and then allowed the cells to further differentiate. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected genes

C

41) Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following? A) Eukaryotic mRNAs get 5' caps and 3' tails. B) Prokaryotic genes are expressed as mRNA, which is more stable in the cell. C) Eukaryotic exons may be spliced in alternative patterns. D) Prokaryotes use ribosomes of different structure and size. E) Eukaryotic coded polypeptides often require cleaving of signal sequences before localization.

C

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

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

In order to be able to remain latent in an infected live cell, HSV must be able to shut down what process? A) DNA replication B) transcription of viral genes C) apoptosis of a virally infected cell D) all immune responses E) interaction with histones

C

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. 16) If she moves the promoter for the lac operon to the region between the beta galactosidase gene and the permease gene, which of the following would be likely? A) Three structural genes will no longer be expressed. B) RNA polymerase will no longer transcribe permease. C) The operon will no longer be inducible. D) Beta galactosidase will be produced. E) The cell will continue to metabolize but more slowly.

C

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. 17) If she moves the operator to the far end of the operon (past the transacetylase 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. E) The repressor protein will no longer be produced

C

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

1) Which enzyme was used to produce the molecule in Figure 20.1? A) ligase B) transcriptase C) a restriction enzyme D) RNA polymerase E) DNA polymerase

C) a restriction enzyme

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

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 cell's DNA.

C

14) How does a genomic library differ from a cDNA library? A) A genomic library contains only noncoding sequences, whereas a cDNA library contains only coding sequences. B) A genomic library varies, dependent on the cell type used to make it, whereas the content of a cDNA library does not. C) A genomic library can be made using a restriction enzyme and DNA ligase only, whereas a cDNA library requires both of these as well as reverse transcriptase and DNA polymerase. D) The genomic library can be replicated but not transcribed. E) The genomic library contains only the genes that can be expressed in the cell.

C) A genomic library can be made using a restriction enzyme and DNA ligase only, whereas a cDNA library requires both of these as well as reverse transcriptase and DNA polymerase.

24) Which of the following seals the sticky ends of restriction fragments to make recombinant DNA? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase

C) DNA ligase

5) A mutation in this section of DNA could influence the binding of RNA polymerase to the DNA: A) operon B) inducer C) promoter D) repressor E) corepressor

C

5) What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes. III. Extract plasmid DNA from bacterial cells. IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. V. Use ligase to seal plasmid DNA to nonplasmid DNA. A) I, II, IV, III, V B) II, III, V, IV, I C) III, II, IV, V, I D) III, IV, V, I, II E) IV, V, I, II, III

C) III, II, IV, V, I

56) One successful form of gene therapy has involved delivery of an allele for the enzyme adenosine deaminase (ADA) to bone marrow cells of a child with SCID, and delivery of these engineered cells back to the bone marrow of the affected child. What is one major reason for the success of this procedure as opposed to many other efforts at gene therapy? A) The engineered bone marrow cells from this patient can be used for any other SCID patient. B) The ADA introduced allele causes all other ADA-negative cells to die. C) The engineered cells, when reintroduced into the patient, find their way back to the bone marrow. D) No vector is required to introduce the allele into ADA-negative cells E) The immune system fails to recognize cells with the variant gene

C) The engineered cells, when reintroduced into the patient, find their way back to the bone marrow.

38) Which describes the transfer of polypeptide sequences to a membrane to analyze gene expression? A) Southern blotting B) Northern blotting C) Western blotting D) Eastern blotting E) RT-PCR

C) Western blotting

22) The major advantage of using artificial chromosomes such as YACs and BACs for cloning genes is that A) plasmids are unable to replicate in cells. B) only one copy of a plasmid can be present in any given cell, whereas many copies of a YAC or BAC can coexist in a single cell. C) YACs and BACs can carry much larger DNA fragments than ordinary plasmids can. D) YACs and BACs can be used to express proteins encoded by inserted genes, but plasmids cannot. E) all of the above

C) YACs and BACs can carry much larger DNA fragments than ordinary plasmids can.

18) A student wishes to clone a sequence of DNA of ~200 kb. Which vector would be appropriate? A) a plasmid B) a typical bacteriophage C) a BAC D) a plant virus E) a large polypeptide

C) a BAC

36) DNA microarrays have made a huge impact on genomic studies because they A) can be used to eliminate the function of any gene in the genome. B) can be used to introduce entire genomes into bacterial cells. C) allow the expression of many or even all of the genes in the genome to be compared at once. D) allow physical maps of the genome to be assembled in a very short time. E) dramatically enhance the efficiency of restriction enzymes.

C) allow the expression of many or even all of the genes in the genome to be compared at once.

10) A principal problem with inserting an unmodified mammalian gene into a bacterial plasmid, and then getting that gene expressed in bacteria, is that A) prokaryotes use a different genetic code from that of eukaryotes. B) bacteria translate polycistronic messages only. C) bacteria cannot remove eukaryotic introns. D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA. E) bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA.

C) bacteria cannot remove eukaryotic introns.

2) Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to A) insert the fragments cut with X directly into the plasmid without cutting the plasmid. B) cut the plasmid with restriction enzyme X and insert the fragments cut with Y into the plasmid. C) cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme.

C) cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme.

6) Bacteria containing recombinant plasmids are often identified by which process? A) examining the cells with an electron microscope B) using radioactive tracers to locate the plasmids C) exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid D) removing the DNA of all cells in a culture to see which cells have plasmids E) producing antibodies specific for each bacterium containing a recombinant plasmid

C) exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid

28) Restriction fragments of DNA are typically separated from one another by which process? A) filtering B) centrifugation C) gel electrophoresis D) PCR E) electron microscopy

C) gel electrophoresis

42) Which of the following techniques used to analyze gene function depends on the specificity of DNA base complementarity? A) Northern blotting B) use of RNAi C) in vitro mutagenesis D) in situ hybridization E) restriction fragment analysis

C) in vitro mutagenesis

34) Which of the following procedures would produce RFLPs? A) incubating a mixture of single-stranded DNA from two closely related species B) incubating DNA nucleotides with DNA polymerase C) incubating DNA with restriction enzymes D) incubating RNA with DNA nucleotides and reverse transcriptase E) incubating DNA fragments with "sticky ends" with ligase

C) incubating DNA with restriction enzymes

11) A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using A) RNA polymerase to transcribe the gene. B) a restriction enzyme to cut the gene into shorter pieces. C) reverse transcriptase to reconstruct the gene from its mRNA. D) DNA polymerase to reconstruct the gene from its polypeptide product. E) DNA ligase to put together fragments of the DNA that codes for a particular polypeptide.

C) reverse transcriptase to reconstruct the gene from its mRNA.

61) As genetic technology makes testing for a wide variety of genotypes possible, which of the following is likely to be an increasingly troublesome issue? A) use of genotype information to provide positive identification of criminals B) using technology to identify genes that cause criminal behaviors C) the need to legislate for the protection of the privacy of genetic information D) discrimination against certain racial groups because of major genetic differences E) alteration of human phenotypes to prevent early disease mRNAs

C) the need to legislate for the protection of the privacy of genetic information

20) Muscle cells and nerve cells in one species of animal owe their differences in structure to A) having different genes. B) having different chromosomes. C) using different genetic codes. D) having different genes expressed. E) having unique ribosomes.

D

23) Genomic imprinting, DNA methylation, and histone acetylation are all examples of A) genetic mutation. B) chromosomal rearrangements. C) karyotypes. D) epigenetic phenomena. E) translocation.

D

25) Two potential devices that eukaryotic cells use to regulate transcription are A) DNA methylation and histone amplification. B) DNA amplification and histone methylation. C) DNA acetylation and methylation. D) DNA methylation and histone acetylation. E) histone amplification and DNA acetylation.

D

28) A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all. Which is a likely explanation for the lack of transgene expression in the fifth cell line? A) A transgene integrated into a heterochromatic region of the genome. B) A transgene integrated into a euchromatic region of the genome. C) The transgene was mutated during the process of integration into the host cell genome. D) The host cell lacks the enzymes necessary to express the transgene. E) A transgene integrated into a region of the genome characterized by high histone acetylation.

D

33) This can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA: A) enhancer B) promoter C) activator D) repressor E) terminator

D

35) 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. E) promoting the formation of looped domains in certain regions of DNA.

D

4) This protein is produced by a regulatory gene: A) operon B) inducer C) promoter D) repressor E) corepressor

D

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

D

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

In electron micrographs of HSV infection, it can be seen that the intact virus initially reacts with cell surface proteoglycans, then with specific receptors. This is later followed by viral capsids docking with nuclear pores. Afterward, the capsids go from being full to being "empty." Which of the following best fits these observations? A) Viral capsids are needed for the cell to become infected; only the capsids enter the nucleus. B) The viral envelope is not required for infectivity, since the envelope does not enter the nucleus. C) Only the genetic material of the virus is involved in the cell's infectivity, and is injected like the genome of a phage. D) The viral envelope mediates entry into the cell, the capsid entry into the nuclear membrane, and the genome is all that enters the nucleus. E) The viral capsid mediates entry into the cell, and only the genomic DNA enters the nucleus, where it may or may not replicate.

D

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

What are prions? A) mobile segments of DNA B) tiny molecules of RNA that infect plants C) viral DNA that has had to attach itself to the host genome D) misfolded versions of normal brain protein E) viruses that invade bacteria

D

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 his or her 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

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 are released at a time. E) The virus-host relationship usually lasts for generations.

D

51) Which of the following are probably siblings? A) A and B B) A and C C) A and D D) C and D E) B and D

D) C and D

CML (chronic myelogenous leukemia) results from a translocation between human chromosomes 9 and 22. The resulting chromosome 22 is significantly shorter than the usual, and it is known as a Philadelphia (Ph') chromosome. The junction at the site of the translocation causes over-expression of a thymine kinase receptor. A new drug (Gleevec or imatinib) has been found to inhibit the disease if the patient is treated early. 58) Which of the following would be a reasonably efficient technique for confirming the diagnosis of CML? A) searching for the number of telomeric sequences on chromosome 22 B) looking for a Ph' chromosome in a peripheral blood smear C) enzyme assay for thymine kinase activity D) FISH study to determine the chromosomal location of all chromosome 22 q fragments E) identification of the disease phenotype in review of the patient's records

D) FISH study to determine the chromosomal location of all chromosome 22 q fragments

57) 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) Most cells with engineered genes overwhelm other cells in a tissue. C) Cells with transferred genes are unlikely to replicate. D) Transferred genes may not have appropriately controlled activity. E) mRNA from transferred genes cannot be translated.

D) Transferred genes may not have appropriately controlled activity

20) Sequencing an entire genome, such as that of C. elegans, a nematode, is most important because A) it allows researchers to use the sequence to build a "better" nematode, resistant to disease. B) it allows research on a group of organisms we do not usually care much about. C) the nematode is a good animal model for trying out cures for viral illness. D) a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates. E) a sequence that is found to have no introns in the nematode genome is likely to have acquired the introns from higher organisms.

D) a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates

44) In 1997, Dolly the sheep was cloned. Which of the following processes was used? A) use of mitochondrial DNA from adult female cells of another ewe B) replication and dedifferentiation of adult stem cells from sheep bone marrow C) separation of an early stage sheep blastula into separate cells, one of which was incubated in a surrogate ewe D) fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate E) isolation of stem cells from a lamb embryo and production of a zygote equivalent

D) fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate

27) Which of the following separates molecules by movement due to size and electrical charge? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase

D) gel electrophoresis

Use the following information to answer the questions below. A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. 7) Bacteria that contain the plasmid, but not the eukaryotic gene, would grow A) in the nutrient broth plus ampicillin, but not in the broth containing tetracycline. B) only in the broth containing both antibiotics. C) in the broth containing tetracycline, but not in the broth containing ampicillin. D) in all four types of broth. E) in the nutrient broth without antibiotics o

D) in all four types of broth.

19) If glucose is available in the environment of E. coli, the cell responds with very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect would then be a measurable effect? A) decreased concentration of the lac enzymes B) increased concentration of the trp enzymes C) decreased binding of the RNA polymerase to sugar metabolism-related promoters D) decreased concentration of alternative sugars in the cell E) increased concentrations of sugars such as arabinose in the cell

E

24) Approximately what proportion of the DNA in the human genome codes for proteins or functional RNA? A) 83% B) 46% C) 32% D) 13% E) 1.5%

E

27) In eukaryotes, transcription is generally associated with A) euchromatin only. B) heterochromatin only. C) very tightly packed DNA only. D) highly methylated DNA only. E) both euchromatin and histone acetylation.

E

3) The tryptophan operon is a repressible operon that is A) permanently turned on. B) turned on only when tryptophan is present in the growth medium. C) turned off only when glucose is present in the growth medium. D) turned on only when glucose is present in the growth medium. E) turned off whenever tryptophan is added to the growth medium.

E

34) This is the site in the DNA located near the end of the final exon, encoding an RNA sequence that determines the 3' end of the transcript: A) enhancer B) promoter C) activator D) repressor E) terminator

E

38) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. One of her colleagues suggested she try increased methylation of C nucleotides in a mammalian system. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected genes

E

6) A lack of this nonprotein molecule would result in the inability of the cell to "turn off" genes: A) operon B) inducer73 C) promoter D) repressor E) corepressor

E

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 similar to the genome of the host cell.

E

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. 18) If she moves the repressor gene (lac I), along with its promoter, to a position at some several thousand base pairs away from its normal position, which will you expect to occur? A) The repressor will no longer be made. B) The repressor will no longer bind to the operator. C) The repressor will no longer bind to the inducer. D) The lac operon will be expressed continuously. E) The lac operon will function normally.

E

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 enzymes produced by the virus before it infects the cell. E) the proteins on its surface and that of the host.

E

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

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

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

E

29) In order to identify a specific restriction fragment using a probe, what must be done? A) The fragments must be separated by electrophoresis. B) The fragments must be treated with heat or chemicals to separate the strands of the double helix. C) The probe must be hybridized with the fragment. D) Only A and B are correct. E) A, B, and C are correct.

E) A, B, and C are correct.

39) Which uses reverse transcriptase to make cDNA followed by amplification? A) Southern blotting B) Northern blotting C) Western blotting D) Eastern blotting E) RT-PCR

E) RT-PCR

59) Why would Gleevec most probably cause remission of the disease? A) It reverses the chromosomal translocation. B) It eliminates the Ph' chromosome. C) It removes Ph'-containing progenitor cells. D) The drug inhibits the replication of the affected chromosome. E) The drug inhibits the specific thymine kinase receptor.

E) The drug inhibits the specific thymine kinase receptor.

17) A researcher needs to clone a sequence of part of a eukaryotic genome in order to express the sequence and to modify the polypeptide product. She would be able to satisfy these requirements by using which of the following vectors? A) a bacterial plasmid B) BAC to accommodate the size of the sequence C) a modified bacteriophage D) a human chromosome E) a YAC with appropriate cellular enzymes

E) a YAC with appropriate cellular enzymes

15) Yeast artificial chromosomes contain which of the following elements? A) centromere only B) telomeres only C) origin of replication only D) centromeres and telomeres only E) centromere, telomeres, and an origin of replication

E) centromere, telomeres, and an origin of replication

53) Genetic engineering is being used by the pharmaceutical industry. Which of the following is not currently one of the uses? A) production of human insulin B) production of human growth hormone C) production of tissue plasminogen activator D) genetic modification of plants to produce vaccines E) creation of products that will remove poisons from the human body

E) creation of products that will remove poisons from the human body

43) Which of the following is most closely identical to the formation of twins? A) cell cloning B) therapeutic cloning C) use of adult stem cells D) embryo transfer E) organismal cloning

E) organismal cloning