Microbiology 13-18

1. As prokaryotes normally only have one set of genes, they are called __________.

haploid

2. The __________ is the collection of characteristics of an organism that an investigator observes.

phenotype

3. The __________ describes the specific set of genes an organism possesses.

genotype

4. Hershey and Chase demonstrated that when the bacteriophage T2 infected its host cell, the __________ is injected into the host but the __________ remained outside.

DNA; protein

5. The two strands of a DNA molecule are __________; that is, they are oriented in opposite directions.

antiparallel

6. A consensus sequence in the untranslated leader sequence of a prokaryotic mRNA which serves as a ribosome binding site is called the __________ sequence.

Shine-Dalgarno

7. mRNA molecules have a nontranslated sequence called the __________, which is located downstream of the termination codon.

trailer

8. On mRNA molecules, a nontranslated sequence called the ___________ usually precedes the initiation codon.

leader

9. Messenger RNA molecules that direct the synthesis of more than one polypeptide are said to be __________.

polycistronic

10. Aminoacyl-tRNA synthetases catalyze covalent addition of __________ __________ to tRNAs.

amino acids

11. Proteins that recognize unfolded polypeptides and help them fold into their proper conformations are called ______________.

chaperones

12. Which of the following individuals or groups of individuals demonstrated that the transforming principle was DNA?

A. Avery, MacLeod, and McCarty

13. The principle of transformation was first demonstrated by which of the following individuals or groups of individuals?

B. Griffith

14. DNA functions as a storage molecule, holding genetic information for the lifetime of a cellular organism and allowing that information to be duplicated and passed on to its progeny.

TRUE

15. The genetic information in DNA is divided into units called

B. genes.

16. The B form of the DNA double helix contains a wider major groove and a narrower minor groove because the two polynucleotide strands are not positioned directly opposite one another in the helical cylinder.

TRUE

17. The basic differences between RNA and DNA reside in their sugar and pyrimidine bases; RNA has ribose and uracil whereas DNA has deoxyribose and thymine.

TRUE

18. Which of the following is not a pyrimidine?

A. adenine

19. Which of the following is not a complementary base pair usually found in DNA molecules?

C. adenine-uracil

20. Which of the following is true about the structure of DNA?

A. Purine and pyrimidine bases are attached to the 1′-carbon of the deoxyribose sugars.B. Purine and pyrimidine bases are joined by phosphodiester bonds.C. Adjacent bases are stacked on top of each other, one base pair every 0.34 nm.D. all of the choices

21. DNA replication is a complex process, and as a result the frequency of error is quite high.

FALSE

22. Which of the following nitrogenous bases is usually found in RNA but not in DNA?

C. uracil

23. Bacterial chromosomes, unlike eukaryotic chromosomes, often consist of a single replicon.

TRUE

24. When a DNA molecule is replicated, the daughter molecules contain one strand of parental DNA and one strand of newly synthesized DNA; this is called __________ replication.

C. semiconservative

25. The chromosomes of most bacteria are comprised of

A. double-stranded circular molecules.

27. Each chromosome has one or more __________ site(s) where replication begins.

C. origin

29. Over twisting or under twisting of helical DNA generates

D. supercoils.

26. The Y-shaped part of the DNA molecule where the actual replication process occurs is called the replication __________.

^B. fork

28. During replication the 2 strands of the DNA molecule are unwound from one another by enzymes called

^C. helicases.

30. Prokaryotic DNA replication occurs at a rate of

A. 750-1,000 base pairs per second.

31. The coding sequence in the DNA of __________ is normally continuous; that is, it is not interrupted by noncoding sequences.

A. prokaryotes

32. Which of the following is not considered the final product of the expression of a gene?

B. An mRNA molecule.

33. The transcribed, but not translated, sequence that is immediately upstream of the region that encodes the functional product is called the __________ region.

A. leader

34. The region at which the RNA polymerase binds is the __________ region.

B. promoter

35. The transcribed and translated region of a gene is the __________ region.

C. coding

37. The unexpressed regions of split genes are called

C. introns.

38. A bacterial __________ is the nontranscribed region of the DNA to which RNA polymerase binds in order to initiate transcription.

C. promoter

39. A section of DNA that codes for a protein or other functional product is called a(n)

B. gene.

36. Which of the following is in the coding region of a gene?

none of the choices

42. The Pribnow box of E. coli

C. is centered approximately 10 bp upstream of the start site of transcription.

43. The process by which the base sequence of all or a portion of a DNA molecule is used to direct the synthesis of an RNA molecule is called

B. transcription.

44. When RNA polymerase catalyzes the addition of a nucleotide to a growing mRNA chain, a byproduct of this reaction is

B. pyrophosphate.

45. Key sequences exist within promoters, which vary somewhat among various promoters but are sufficiently constant that they can be represented by a sequence of bases most often found at each position. These representations are called __________ sequences.

C. consensus

46. The genetic code is said to be __________ because more than one codon will specify a particular amino acid.

B. degenerate

which of the following is not a termination codon?

A. AUG

40. The strand of DNA for a particular gene that is copied by the RNA polymerase to form mRNA is called the __________ strand.

^B. template

48. Which of the following is the initiator codon?

A. AUG B. UAA C. UAG D. UGA

41. The noncoding sequences located between the start codon and the stop codon in interrupted genes are called introns.

true

49. The genetic code is translated in groups of __________ bases.

B. three

52. The process by which the base sequence of an RNA molecule is used to direct the synthesis of a protein is called

D. translation.

51. How many different termination codons are used in translation?

three

53. The stop codons are translated codons; that is, they specify amino acids to be inserted into the last position of a growing polypeptide chain.

FALSE

54. The portion of the tRNA molecule that binds to the codon on the mRNA is called the

B. anticodon.

55. What is the minimum number of aminoacyl-tRNA synthetase enzymes needed to attach amino acids to all the various tRNA molecules?

A. 20.

56. In __________ ribosomes can attach to the mRNA and begin translation even though transcription has not been completed.

A. prokaryotes

57. Ribosomes consist of __________ separate subunits that come together as part of the initiation process and dissociate immediately after termination.

A. two

58. The __________ reaction sequentially links adjacent amino acids into the growing polypeptide chain.

B. transpeptidation

59. A complex consisting of a single mRNA molecule with several ribosomes is called a

A. polysome.

60. In order to add a single amino acid to a growing polypeptide chain, a grand total of __________ molecules or ATP or GTP are utilized.

B. three

61. All prokaryotes initiate the synthesis of proteins with formylmethionine.

FALSE

62. The energy needed for protein synthesis is provided by the hydrolysis of

D. ATP and GTP.

63. Some microbial proteins are spliced after translation in a reaction that results in removal of one or more internal intervening sequences called inteins.

TRUE

1. When arabinose is present in the environment, the AraC protein acts as a(n) ______________ for the E. coli ara operon.

activator

2. When there is no arabinose available in the environment, the AraC protein acts as a(n) ______________ for the E. coli ara operon.

repressor

50. ________ molecules deliver amino acids to ribosomes during translation.

transfer RNA(tRNA)

3. If a set of genes is repressed in the presence of the controlling substance, it is referred to as __________ control.

negative

4. If a set of genes is induced in the presence of the controlling substance, it is referred to as __________ control.

positive

5. The binding of arabinose to the AraC protein allows it to form a loop in the DNA upstream of the ara operon promoter.

FALSE

6. Two-component signal transduction systems are found in the Bacteria, but not in Archaea.

FALSE

7. The real inducer for the E. coli lac operon is allolactose produced by the action of permease on lactose.

FALSE

8. In the presence of both glucose and lactose, the lactose repressor is not bound to the operator and the genes of the lactose operon are expressed.

FALSE

9. Small RNAs that regulate translation by binding to the leader region of mRNAs are called antisense RNAs.

TRUE

10. ____________ is used to measure the amount of a chemoattractant encountered over time.

Methylation

11. One way to regulate gene expression is through the production of different sigma factors. These cause RNA polymerase to bind to different sets of promoters, thereby altering the pattern of gene expression.

TRUE

12. Gene regulation during sporulation in Bacillus subtilis involves BOTH temporal and spatial control.

TRUE

13. In order for high level expression of the E. coli lac operon to occur, a complex of catabolite activator protein and __________ must be bound to the DNA near the promoter.

cAMP

14. A collection of genes or operons controlled by a common regulatory protein is called a(n) ___________.

regulon

15. Regulation of gene expression serves to do all of the following except

C. adjust the activity of existing proteins in the cell.

16. In two component regulatory systems, the response regulator typically receives a ____________ from the sensor kinase when it has been activated.

B. phosphoryl group

17. While standard two-component regulatory systems typically act to control gene transcription, phosphorelay systems can act either to control gene transcription or to control

B. protein activity.

18. The sensor kinase for the OmpF: OmpC two-component regulatory system is

B. the EnvZ protein.

20. So-called two-component regulatory systems

A. include a sensor kinase and a response regulator.B. play a key role in regulating sporulation in Bacillus.C. play a key role in regulating the OmpF and OmpC porin proteins in E. coli.D. all of the choices

19. The E. coli lac operon has ________ operator sequences.

three

21. If Escherichia coli is cultured in broth containing both glucose and lactose, it

A. uses glucose preferentially until the supply is exhausted, then uses lactose.

22. __________ activate repressor proteins thereby decreasing the synthesis of certain enzymes.

B. Corepressors

23. __________ alter repressor proteins thereby increasing the rate of transcription initiation.

A. Inducers

24. ______________ is used to control transcription of some anabolic pathways involved in amino acid biosynthesis.

A. Attenuation

25. When a repressor binds to the operator site on the DNA it normally

A. inhibits the initiation of transcription.

26. Enzymes that are expressed at a constant level all the time are said to be:

C. constitutive.

27. Which of the following is not a regulatory mechanism used to control the tryptophan operon in Escherichia coli?

B. catabolite repression

28. Which of the following is not a regulatory mechanism used to control the lactose operon in Escherichia coli?

C. attenuation

29. The site on the DNA to which a repressor protein binds is the __________.

B. operator

30. When bound to the DNA, the repressor protein usually prevents attachment of the RNA polymerase to the __________.

C. promoter

32. What is the key factor determining whether or not attenuation will occur when transcription of the E. coli trp operon has been initiated?

D. The level of trp-tRNA that is charged with tryptophan.

33. With the E. coli trp operon where both repression and attenuation occur, the extent of regulation achieved by repression is _____________ the extent of regulation achieved by attenuation.

C. greater than

34. The terminator versus anti-terminator function of the T box-based riboswitch used by Gram-positive bacteria to regulate amino acid-related genes is determined by

A. the binding of the appropriate uncharged tRNA.

35. Most E. coli antisense RNAs work with a protein called ______ to regulate their target mRNAs.

C. Hfq

36. Riboswitches that can block the initiation of translation because of a conformational change that occurs in the leader sequence of an mRNA when the appropriate regulatory effector binds the mRNA achieve that blockage of translation initiation by the occlusion of

C. the Shine-Delgarno sequence.

37. Posttranslational regulation occurs after a protein has been synthesized, and can occur by

D. allosteric regulation and covalent modification are both means of regulation after translation is complete.

31. The __________ is a factor-independent termination site found in the leader region of certain operons, which, under the influence of ribosome behavior, controls the continued transcription of that operon.

attenuator

38. What term describes a set of genes that is controlled by a common regulatory protein?

B. regulon

39. In some circumstances, when two different carbon sources are available, growth will occur first using one carbon source, then after a short lag period, growth will resume using the second carbon source. This process is called __________ growth.

C. diauxic

40. The activity of adenyl cyclase is influenced by

A. the phosphotransferase system.

41. An operon network that is under the control of a common regulatory protein while each operon is still also under the control of its own unique regulatory protein is most specifically referred to as a

C. modulon.

42. The standard or housekeeping sigma factor used most often by E. coli RNA polymerase under normal growth conditions is called sigma ___.

70

Acylhomoserine lactones used in quorum sensing regulate their own synthesis by a(n) ____________ system.

^D. autoinduction

44. During sporulation in Bacillus subtilis, the response regulator that positively controls many genes needed for sporulation and negatively controls genes not needed during sporulation is

B. SpoOA.

45. During the early stages of sporulation in Bacillus subtilis, ________ is active in the forespore and ________ is active in the mother cell.

D. F; E

46. During sporulation in Bacillus subtilis, inactive precursor forms of new sigma factors are activated at the appropriate time by

A. proteolysis.

47. The sensing of starvation that leads to sporulation in Bacillus subtilis is accomplished by a(n)

B. sensor kinase.

48. Cell-to-cell communication by quorum sensing has been shown to be important in the regulation of genes needed for

A. virulence.B. biofilm production.C. plasmid transfer.D. all of the choices.

49. When the Catabolite Activator Protein binds to its binding site in DNA, it

B. bends the DNA.

1. DNA replication is a complex process, and as a result the frequency of error is quite high.

FALSE

2. Because of its larger size, the replication rate of eukaryotic genomes is significantly faster than the replication rate of prokaryotic genomes.

FALSE

3. Bacterial chromosomes, unlike eukaryotic chromosomes, often consist of a single replicon.

TRUE

4. When a DNA molecule is replicated, the daughter molecules contain one strand of parental DNA and one strand of newly synthesized DNA; this is called __________ replication.

C. semiconservative

5. The chromosomes of most bacteria are comprised of

A. double-stranded circular molecules.

6. Each chromosome has one or more __________ site(s) where replication begins.

C. origin

7. The transcribed, but not translated, sequence that is immediately upstream of the region that encodes the functional product is called the __________ region.

A.

8. The region at which the RNA polymerase binds is the __________ region.

B. promoter

9. The unexpressed regions of split genes are called

C. introns.

10. A bacterial __________ is the nontranscribed region of the DNA to which RNA polymerase binds in order to initiate transcription.

C. promoter

11. Split or interrupted genes have been found in eukaryotes but not in prokaryotes.

TRUE

12. A consensus sequence in the untranslated leader sequence of a prokaryotic mRNA which serves as a ribosome binding site is called the __________ sequence.

Shine-Dalgarno

13. Splicing of eukaryotic heteronuclear RNA is catalyzed by ______________.

snRNPs

14. In eukaryotes a so-called cap consisting of __________ is attached to the 5′ end of the molecule during posttranscriptional modification of hnRNA to produce functional mRNA.

7-methylguanosine

15. Eukaryotic mRNAs are modified by addition of a poly(A) sequences at the 3′ end and 7-methyl guanosine at the 5′ end.

TRUE

16. RNA polymerase III of eukaryotes is responsible for transcribing

C. tRNA.

17. RNA polymerase II of eukaryotes is responsible for transcribing

B. mRNA.

18. The Pribnow box of E. coli

C. is centered approximately 10 bp upstream of the start site of transcription.

19. The process by which the base sequence of all or a portion of a DNA molecule is used to direct the synthesis of an RNA molecule is called

B. transcription

20. In eukaryotes a series of __________ residues are added to the 3′ end of an RNA molecule as part of the posttranscriptional processing used to produce functional mRNA.

A. adenine

21. Key sequences exist within promoters, which vary somewhat among various promoters but are sufficiently constant that they can be represented by a sequence of bases most often found at each position. These representations are called __________

C. consensus

22. The genetic code is said to be __________ because more than one codon will specify a particular amino acid.

B. degenerate

23. The genetic code is translated in groups of __________ bases.

B. three

24. ________ molecules deliver amino acids to ribosomes during translation.

B. Transfer RNA (tRNA)

25. The process by which the base sequence of an RNA molecule is used to direct the synthesis of a protein is called

D. translation.

26. What is the minimum number of aminoacyl-tRNA synthetase enzymes needed to attach amino acids to all the various tRNA molecules?

A. 20

27. In __________ ribosomes can attach to the mRNA and begin translation even though transcription has not been completed.

A. prokaryotes

28. Ribosomes consist of __________ separate subunits that come together as part of the initiation process and dissociate immediately after termination.

A. two

29. A complex consisting of a single mRNA molecule with several ribosomes is called

a A. polysome.

30. In order to add a single amino acid to a growing polypeptide chain, a grand total of __________ molecules or ATP or GTP are utilized.

B. three

31. Aminoacyl-tRNA synthetases catalyze covalent addition of __________ __________ to tRNAs.

amino acids

32. Proteins that recognize unfolded polypeptides and help them fold into their proper conformations are called ______________.

chaperones

33. Many archaeal genomes include plasmids

TRUE

34. Most archaeal mRNAs like those of eukaryotes are spliced.

FALSE

35. Unlike other prokaryotes, archaeons (except Sulfolobus) have two origins of replication.

FALSE

36. Unlike members of the Bacteria, most archaeons have linear chromosomes with multiple origins of replication.

FALSE

37. Archaeal promoters are most similar to those of

C. eukaryotes.

38. Which of the following is not true about archaeal ribosomes?

C. They have similar antibiotic sensitivities to those of bacteria.

39. The Archaea do not use __________ as a mechanism for reproduction.

C. mitosis

1. A mutation from the most prevalent form of a gene to a mutant form is called a __________ mutation.

A. forward

2. A mutagen that inserts between the stacked bases of a DNA double helix, distorting the DNA to induce single-pair insertions or deletions is called a(n) __________ agent.

C. intercalating

3. Spontaneous mutations are caused by A. errors in DNA replication. B. insertion of transposons.

D. errors in DNA replication and insertion of transposons

4. A __________ mutation does not alter the amino acid sequence of the resulting protein.

C. silent

5. As the result of exposure to a mutagen, cytosine is substituted for thymine in one strand of DNA. Upon subsequent DNA replication, one of the daughter cells will have a GC pair in this position instead of an AT pair. This is called a(n) __________ mutation.

B. transition

6. Which of the following can lead to transition mutations?

C. Incorporation of a base analog that exhibits different base-pairing properties from the base it replaces and chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base.

7. Which of the following is considered a reverse mutation that will restore the wild type phenotype?

A. True reversion back to the wild type base sequence. B. Mutation to a different base sequence, but one that restores the amino acid sequence in the protein to the wild type sequence. C. A mutation that restores the function of a protein even though it does not restore the base sequence or the amino acid sequence to the wild type. D. All of the choices.

8. Which of the following types of mutation may play an important role in driving evolution because they are often nonlethal and, therefore, remain in the gene pool?

B. missense

9. A mutation that changes the amino acid sequence of the resulting protein by substitution is called a __________ mutation.

A. missense

10. _______ are strains that are unable to grow on a minimal medium that supports growth of the wild type strain but are able to grow on the minimal medium if one or more nutritional supplements are added.

B. Auxotrophs

11. Mutations that result in the death of an organism when expressed are called __________ mutations.

C. lethal

12. Lethal mutations can be maintained in diploid organisms if they are

B. recessive.

13. Lethal mutations can be recovered in haploid organisms if they are

C. conditional.

14. A __________ mutation is one that causes premature termination of the synthesis of the protein product.

B. nonsense

15. The __________ __________ is the most prevalent form of a gene in a population.

wild type

16. __________ are physical or chemical agents that cause mutation.

Mutagens

17. __________ mutations affect only a single base pair in a gene.

Point

18. Mutations resulting from exposure to physical or chemical agents are called __________ mutations.

induced

19. __________ mutations occur in the promoter or operator region of a gene or set of genes and affects the expression of the downstream genes without affecting the amino acid sequences of the gene products.

Regulatory

20. Microbial strains that can grow on minimal medium are called __________.

C. prototrophs

21. Which one of the following contributes to the utility of the strains of Salmonella typhimurium used in the Ames reversion assay?

A. They are highly permeable to test substances. B. They are defective in DNA repair and, therefore, cannot readily repair damage done by the test substances. C. It is very straightforward to assay the conversion of their histidine auxotrophy mutations to histidine prototrophy. D. all of the choices

22. The Ames test

A. can be used to measure the mutagenicity of chemicals.

23. In mismatch repair on newly replicated DNA, enzymes distinguish between old and newly replicated DNA strands based on the fact that newly replicated DNA strands are ________ methylated relative to older DNA.

under (or less)

24. Photoreactivation repairs thymine dimers by splitting them back into separate thymines.

TRUE

25. Approximately half of known animal carcinogens can be detected by the Ames test.

TRUE

26. Repair of an apurinic or apyrimidinic site in DNA by AP endonuclease must be completed by the action of

C. DNA polymerase I.

27. Repair of thymine dimers using light to split the dimers apart into separate monomers is called

B. photoreactivation.

28. Which of the following is the most error-prone of the repair mechanisms?

C. SOS repair

29. SOS repair

A. requires RecA protein. B. is inducible by DNA damage. C. is error prone, i.e., produces mutations. D. all of the choices

30. __________ __________ is the process by which some cells are capable of degrading an exogenote.

Host restriction

31. Alternate forms of genes resulting from mutations are called

C. alleles.

32. Transfer of genes from one mature independent organism to another is called

A. horizontal gene transfer.

33. Which of these transposable elements do not carry genes for functions other than those needed for transposition?

A. insertion sequences

34. Which of the following is a possible fate for an exogenote?

A. Integration into the host chromosome. B. Independent replication and functioning. C. Degradation to nucleotides. D. All of the choices.

35. Which of the following is true of the integration of a viral genome into the host chromosome?

D. It is a form of site-specific recombination and the enzymes are specific for the virus and its host.

36. When bacterial genes are transferred to another bacterium by a virus, it is called

C. transduction.

37. When a recipient cell acquires a piece of naked DNA from the environment, it is called

B. transformation.

38. The process in which one or more nucleic acid molecules are rearranged or combined to produce a new nucleotide sequence is called

C. recombination.

39. A reciprocal exchange in which a pair of DNA with the same nucleotide sequence break and rejoin in a crossover is called __________ recombination.

A. homologous

40. Site-specific recombination systems

A. do not depend on extensive nucleotide sequence homology. B. depend on enzymes that are often specific for sequences within the host. C. are features of some viruses. D. All of the choices are true.

41. The incorporation of a single strand of donor DNA into a recipient DNA duplex so that the donor strand replaces one of the strands or the recipient duplex generates __________ DNA.

D. heteroduplex

42. DNA molecules that enter a bacterium by one of several mechanisms is called a(n)

B. exogenote.

43. The genome of a recipient cell is called a(n) __________.

C. endogenote

44. A recipient cell that is temporarily diploid for a portion of the genome during the replacement process is called a(n) __________.

A. merozygote

45. Plasmids that have genes that decrease bacterial susceptibility to antibiotics are called __________ factors.

B. resistance

46. Which of the following effects may be mediated by transposable elements?

A. Insertion into a gene, causing a mutation. B. Activation of nearby genes. C. Formation of genetic deletions. D. All of the choices.

47. Conjugative transposons

B. may be involved in the spread of antibiotic resistance in bacteria.

48. Insertion sequences are

A. normally relatively short (700 to 1,650 bp). B. capable of transposition. C. are discrete genetic elements bounded at both ends with inverted repeats. D. all of the choices

49. Transposons that transpose by inserting a copy at a new location while a copy remains at the original location are said to transpose by _______________ transposition.

D. replicative

50. Transposable elements have been found only in prokaryotes and do not appear to play a major role in eukaryotes.

FALSE

51. Plasmids that have genes for pili and can transfer copies of themselves to other bacteria during conjugation are called __________ plasmids.

conjugative

52. A __________ is a piece of extrachromosomal DNA that has its own replication origin.

plasmid

53. A plasmid that can either exist independently of the chromosome or be integrated into it is called a(n) __________.

episome

54. The conjugation bridge in an Hfr F- mating usually breaks before chromosome transfer is complete; however, because at least part of the plasmid is transferred first, the recipient becomes F+.

FALSE

55. In an F+ F- mating, all or part of the host chromosome usually is transferred to the recipient.

FALSE

56. In the mechanics of conjugation, exclusive of gene transfer, Hfr and F+ strains behave the same.

TRUE

57. In an HFR F+ mating, the conjugation bridge usually breaks before chromosomal transfer is complete. Therefore, the recipient remains F-.

TRUE

58. Transfer of genetic information via direct cell-cell contact is called

D. conjugation.

59. Who is credited with demonstrating unidirectional and nonreciprocal transfer of DNA between two mating E. coli cells?

A. Hayes

60. When an F’ plasmid acts as the donor in a mating, which of the following do(es) not happen?

C. Some chromosomal genes not on the plasmid are transferred.

61. An F’ plasmid results when

C. an integrated F plasmid is incorrectly excised, bringing host genes with it.

62. Complete transfer in an Hfr F- mating takes approximately __________ minutes.

C. 100

63. Which of the following best represents the order of gene transfer in an Hfr F- mating?

B. Part of the plasmid followed by the chromosome followed by the rest of the plasmid. .

64. When an F plasmid integrates into the host chromosome, the strain is referred to as

B. Hfr.

65. After an F+ F- mating, the donor is __________ and the recipient is __________.

A. F+; F-

66. In an F+ F- conjugation, the donor is the __________ strain.

A. F+

67. Transformation has been observed in only a limited number of species in nature, but we have found ways to force the process upon other species in the laboratory.

TRUE

68. The transformation frequency of very competent cells is about 10-6, or about 1 in 1,000,000 when an excess of DNA is used.

FALSE

69. In order to take up a naked DNA molecule, a cell must be __________, which may occur only at certain stages in the life cycle of the organism.

competent

70. Which of the following occurs with generalized transduction?

A. Degradation of the host chromosome into randomly sized fragments. B. Packaging of any DNA fragment of the appropriate size. C. Transfer of any bacterial gene to the subsequent host. D. All of these occur with generalized transduction.

71. Specialized transduction can be carried out by

C. only those temperate bacteriophages that integrate into the host chromosome.

72. Which of the following is not true of specialized transduction?

C. The phage genome retains the full complement of phage genes.

73. A __________ is a latent form of a virus genome that remains within the host without destroying it.

prophage

1. The Southern blotting technique for transferring DNA from an agarose gel to a piece of nitrocellulose membrane is named for E. M. Southern, the person who developed the procedure.

TRUE

2. Recombinant DNA technology does not rely on which of the following enzymes?

B. RNA methylase

3. Which of the following is true about restriction endonucleases?

C. Some make a blunt cut on the two DNA strands so that there are no single-strand regions and some make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme.

4. When a eukaryotic gene is cloned into a bacterium, the advantage of a complementary DNA (cDNA) gene being used instead of fragments of genomic DNA is that

B. the introns have been removed from the cDNA gene but not from the genomic fragment.

5. Restriction endonucleases in bacteria may have evolved in order to

B. protect the bacteria from infection by viruses. C. use nucleic acids as a food (energy) source.

6. Cloning a gene involves all of the following except

C. expression of the vector and the gene in a cell-free environment.

7. An enzyme that cleaves internal phosphodiester bonds of a DNA molecule is a

B. endonuclease.

8. Complementary DNA (cDNA) probes are produced using

D. reverse transcriptase.

9. A __________ is a DNA molecule used in hybridization reactions to detect the presence of a particular gene in separated DNA fragments.

C. probe

10. In order to express eukaryotic genes in a bacterium, the __________ must first be removed.

A. introns

11. Which of the following was first produced commercially using recombinant DNA technology?

D. Human insulin.

12. The enzyme reverse transcriptase was discovered by

D. Temin and Baltimore.

13. Restriction endonucleases were discovered by

A. Arber and Smith.

14. Restriction endonucleases are produced by

B. bacteria

15. Genetic engineering methods have been used to produce vaccines.

TRUE

16. The production of large quantities of a particular DNA sequence is known as gene __________________.

amplification

17. The thermostable enzyme most commonly used in PCR is reverse transcriptase.

FALSE

18. The three steps that take place in each cycle during PCR occur in which order?

B. DNA denaturation, annealing, and synthesis.

19. A PCR procedure that allows a determination of the amount of a particular DNA fragment that is present in a sample is called

C. real-time PCR

20. The PCR method was developed by

B. Mullis.

21. The polymerase chain reaction (PCR) can be used to produce __________ of copies in a few hours.

D. billions

22. Movement of charged molecules in an electrical field, which is used to separate nucleic acid fragments for recombinant DNA work, is called

C. electrophoresis.

23. Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?

D. The smallest fragments will migrate fastest.

24. Which of the following is not true of cloning vectors?

B. They contain at least two replication origins

25. Which of the following can be used as vectors for cloning DNA fragments?

A. plasmids. B. cosmids. C. bacteriophages. D. all of the choices.

26. Plasmid cloning vector DNA is usually introduced into bacterial hosts by

B. transformation.

27. Plasmid vectors often contain __________ genes that can be used to screen for recombinants.

B. antibiotic resistance

28. A DNA molecule used to carry a foreign gene into a host organism is called

B. vector.

29. Antibiotics incorporated into the culture medium can

A. select against organisms that have not incorporated the plasmid.

30. A (n) __________ vector is a plasmid that can be replicated in several different organisms because it has at least one origin of replication that will function in each host.

A. shuttle

31. ___________ is a bacterial plasmid vector.

C. pUC19

32. Which of the following is not part of a yeast artificial chromosome (YAC)?

A. The F factor.

33. Which of the following types of cloning vector can carry the largest amount of foreign DNA?

A. bacterial artificial chromosome.

34. Cosmids are plasmids that can be packaged into capsids of the bacteriophage lambda; therefore, they can be transmitted like phages, but they can exist and replicate in a cell like plasmids.

TRUE

35. Transposons are frequently used as cloning vectors.

FALSE

36. Cosmids are so named because they can be used to express foreign genes in a variety of different hosts.

FALSE

37. Regardless of the exact approach taken to recombinant DNA technology, one of the keys to successful cloning is choosing the right vector.

TRUE

38. One of the major advantages to using plasmids as cloning vectors is that very high copy numbers can be achieved with many types of plasmid vectors.

TRUE

39. A(n)__________ __________ is a piece of DNA with all of the features necessary for chromosomal replication and which can carry large (up to 1000 kb) pieces of foreign DNA into a host organism.

artificial chromosome

40. A genomic __________ is a sufficiently large collection of recombinant DNA molecules in which the inserted sequences together represent the entire genome of an organism.

library

41. Promoters for genes that code for proteins can be isolated from a cDNA library.

FALSE

42. In _____________, cells are mixed with recombinant DNA and exposed to a brief pulse of high-voltage electricity to cause the membrane to become permeable and allow the uptake of DNA from its environment.

electroporation

43. Electroporation is commonly used to introduce recombinant DNA molecules into cells.

TRUE

44. When a eukaryotic gene is expressed in a bacterium, the eukaryotic regulatory sequences should be maintained in order to achieve maximum expression of the gene.

FALSE

45. A (n) __________ vector contains promoters that result in high-level transcription of the gene cloned within a multicloning site.

C. expression

46. Some plasmid vectors have incorporated the regulatory sequences of the lactose operon so that the expression of the recombinant gene can be induced at the appropriate time.

TRUE

47. The most frequently chosen prokaryotic host in cloning techniques is

D. Escherichia coli.

1. The method of nucleotide sequence determination that utilizes dideoxynucleotides was developed by _________.

Sanger

2. Modern automated sequencing machines detect DNA bands by measuring incorporated radioactivity.

FALSE

3. Dideoxynucleotide sequencing methodologies rely on the ability of dideoxynucleotides to facilitate chain extension after incorporation by DNA polymerase.

FALSE

4. Each of the four Sanger sequencing reactions include

B. a single dideoxynucleotide triphosphate.

5. Most automated nucleotide sequencing machines detect bands by

A. laser induced fluorescence

6. The Sanger sequencing approach developed in the 1970s

B. is still the main approach used to determine nucleotide sequences.

7. Genomics is the study of

A. the molecular organization of genomes. B. the information content of genomes. C. the gene products that genomes encode. D. all of the choices

8. Automated nucleotide sequencing machines detect DNA bands by laser induced _________.

fluorescence

9. After completing the nucleotide sequence of a microbial genome, computer translation of DNA sequence allows enzymes to be identified based on a short pattern of amino acid sequence called a contig that corresponds to the active site of the enzyme.

FALSE

10. The whole-genome shotgun approach is useful for sequencing small bacterial genomes but has failed in the case of larger eukaryotic genomes such as those of Drosophila and human.

FALSE

11. In genomic research the term contig refers to overlapping nucleotide sequences that are not adjacent in the genome and are formed from smaller fragments.

FALSE

12. Clonal libraries used to determine the sequence of a microbial genome using the whole-genome shotgun approach are typically generated by

A. cloning small gene sized DNA fragments produced by breaking chromosomal DNA with ultrasonic waves

13. The whole-genome shotgun approach for collecting the data used to determine the nucleotide sequence of microbial genomes uses

D. powerful computers and specialized software and automated sequencing of random fragments of genomic DNA

14. An acronym that describes sequences of a protein-coding gene that specify the amino acid sequence is ________.

ORF

15. The proteome refers to the collection of open reading frames in a genome.

FALSE

16. ORF refers to

B. the region of a gene that codes for a protein or a functional RNA product.

17. When two or more genes from the same genome have nucleotide sequences so alike that they most probably arose from gene duplication those genes are called

C. paralogs

18. _______________ is the field concerned with the management and analysis of biological data using computers.

Bioinformatics

19. Nucleic acids to be analyzed using microarrays are usually tagged by covalent attachment of ___________ molecules.

flourescent

20. ______________ technology can be used to simultaneously monitor the level of expression of every gene in a cell.

Microarray

21. Expressed sequence tags are nucleotide sequences derived from cDNA molecules.

TRUE

22. DNA microarray technology is used to measure the

C. levels of specific RNAs expressed by cells.

23. The genome sequence of Treponema pallidum

B. should ultimately help us understand the mechanism by which this organism causes syphilis.

24. Treponema pallidum

B. lacks numerous biosynthetic pathways and thus has numerous nutritional requirements.

25. Analysis of the genome and transcriptome of the highly radiation resistant bacterium Deinococcus radiodurans has revealed all of the following except

B. it has more DNA repair genes than E. coli.

26. The proteome refers to

C. all of the proteins that an organism produces. D. none of the choices

27. Isoelectric focusing

A. separates proteins based on the pH at which they are electrically neutral.

28. Two-dimensional gel electrophoresis

A. separates proteins based on their isoelectric pH. B. separates proteins based on their size. C. can be used to resolve thousands of proteins in a complex mixture. D. all of the choices

29. Protein spots eluted from a 2 dimensional gel analysis can be identified and correlated to specific genes that code for them using

B. mass spectrometry.

30. In modern proteomic analysis the amino acid sequence of a protein can be determined by

B. mass spectrometry.

31. The proteome

C. is the entire collection of proteins that an organism can produce.

32. Since proteins are encoded by nucleotide sequences, the proteome of a microorganism can be readily inferred from the given complete nucleotide sequence of a genome and a high speed computer with specialized software.

FALSE

33. Bioinformatic analysis of genomic nucleotide sequences using specialized software and high-speed computers make it possible to determine how proteins encoded by ORFs are post-translationally modified.

FALSE

34. The term "proteome" refers to the complete amino acid sequence of a protein.

FALSE

35. Research focused on determining the function of different cellular proteins, protein interactions and protein regulation is called _________ proteomics.

functional

36. Isoelectric focusing separates proteins based on the pH at which they are electrically _________.

neutral

37. A long-term goal(s) of the bioinformatic analysis of a pathogenic bacterium is

D. identification of molecules that could be used to develop or improve a vaccine and identification of molecules that can be targeted by antimicrobial agents

38. In an experiment, you have created a microbial strain in which you have deleted a single gene; to evaluate the transcriptome and the proteome, you

D. run microarray analysis and two-dimensional gels.

39. Analysis of the genome of Mycobacterium tuberculosis has revealed all the following except

B. it is more closely related to M. leprae than to M. bovis.

40. The subdiscipline of genomics that seeks to identify similarities and differences between genomes of different strains and species is called __________ genomics.

comparative

41. Genome analysis has revealed that horizontal gene transfer is frequently mediated by phages.

TRUE

42. Mobile genetic elements that are permanently integrated into a microbial genome are known as _________ _________.

genomic islands

43. Mobile genetic elements that encode proteins that contribute to or confer virulence are known as contiguous sequences.

FALSE

44. Which of the following is not a required characteristic of antigens from microbial pathogens that might be used in vaccine production?

D. all of the choices are required characteristics.

45. Analysis of the nucleotide sequence of the genome of microorganisms has revealed important information about their metabolic potential.

TRUE

46. Genomic studies of marine microorganisms has revealed that a considerable amount of the photosynthesis in the ocean is based on photopigments called proteorhodopsins.

TRUE

47. Environmental genomics is sometimes called metagenomics.

TRUE

48. The combination of all the genes present in the human genome and those present in the trillions of microbes living in and on adults is known as the human __________.

metagenome

49. The microbiome represents all the genes present in the trillions of microbes living on and in adult humans.

TRUE