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Molecular Genetics of Prokaryotes

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1. Which of the following is not part of the lac operon of E. coli?

A. genes for inducible enzymes of lactose metabolism
B. genes for the repressor, a regulatory protein
C. gene for RNA polymerase
D. a promoter, the RNA polymerase binding site
E. the operator, the repressor binding site

2. (The role of the inducer of the lac operon). The inducer:

A. combines with a repressor and prevents it from binding to the promoter
B. combines with a repressor and prevents it from binding to the operator
C. binds to the promoter and prevents the repressor from binding to the operator
D. binds to the operator and prevents the repressor from binding at this site
E. binds to the termination codons and allows protein synthesis to continue

3. An E. coli strain is lac Z-. The structural gene for à?-galactosidase is encoded at the lac Z locus. How would you describe the regulation of lactose metabolism in these cells?

A. normal regulation of lactose metabolism
B. constitutive expression of lac Z+
C. inability to synthesize the lac Z+ gene product, à?-galactosidase
D. lac Z+ gene is inducible, but unable to be repressed by high glucose
E. no synthesis of the lac I gene product, the lac repressor

4. Cells of an E. coli strain that are trp- lac Z-met+bio+were mixed with cells of an E. coli strain that are trp+lac Z+ met- bio-and cultured for several hours. Then cells were removed, washed, and transferred to minimal media containing lactose as the only sugar source. A few cells were able to grow on minimal media with lactose, and formed colonies. How did these few cells become trp+ lac Z+ met+bio+?

A. transformation
B. transduction
C. sexduction
D. conjugation
E. transposition

5. An E. coli strain is F- lac Z- met+ bio+. Cells from this strain are mixed with an E. coli strain that is lac Z+ met- bio-and carrying an F' episome with the Plac O+ lac Z+ DNA sequence on the episome, and cultured for several hours. Then cells were removed, washed, and transferred to minimal media containing lactose as the only sugar source. A few cells were able to grow on minimal media with lactose, and formed colonies. How did these few cells become lac Z+ met+ bio+?

A. transformation
B. transduction
C. sexduction, a special type of conjugation
D. conjugation
E. transposition

6. How many lac Z genes were present in the cells described in problem 5 that were able to grow on minimal media?

A. Only 1, the lac Z- allele on the bacterial chromosome.
B. Only 1, the lac Z+ allele on the bacterial chromosome.
C. Two, the lac Z- allele on the bacterial chromosome and the lac Z+ allele on the bacterial chromosome. Two, the lac Z- allele on the bacterial chromosome and the lac Z+ allele on the bacterial chromosome.
D. Two, the lac Z- allele on the bacterial chromosome and the lac Z+ allele on the F' episome
E. Only 1, the lac Z+ allele on the F' episome

7. How would you describe the regulation of lactose metabolism in the cells described in problem 5 that were able to grow on minimal media with lactose as a nutrient?

A. normal regulation of lactose metabolism
B. constitutive expression of lac Z+
C. inability to synthesize the lac Z+ gene product, b-galactosidase
D. lac Z+ gene is inducible, but unable to be repressed by high glucose
E. no synthesis of the lac I gene product, the lac repressor

8. An E. coli strain that is lac Z- is conjugated with E. coli cells carrying an F' plasmid with the Plac Oc- lac Z+ DNA sequence on the episome. The Oc is a mutation of the lactose operator that is no longer able to bind the lac I gene product which codes for the lac repressor. How would the expression of the lac Z+ be regulated in the resulting cells that are diploid for the lactose regulatory region and the lac Z gene?

A. normal regulation of lactose metabolism
B. constitutive expression of lac Z+
C. inability to synthesize the lac Z+ gene product, à?-galactosidase
D. lac Z+ gene is inducible, but unable to be repressed by high glucose
E. no synthesis of the lac I gene product, the lac repressor

9. An E. coli strain is lac I- The lac I+ DNA sequence encodes the lactose repressor. How would you describe the regulation of lactose metabolism in these cells?

A. normal regulation of lactose metabolism
B. constitutive expression of lac Z+
C. inability to synthesize the lac Z+ gene product, à?-galactosidase
D. lac Z+ gene is inducible, but unable to be repressed by high glucose
E. constitutive synthesis of the lac I gene product, the lac repressor

10. An E. coli strain that is lac I- is conjugated with E. coli cells carrying an F' plasmid with the PI -lac I+DNA sequence on the episome. How would the expression of the lac Z+be regulated in the resulting cells that are diploid and heterozygous for the lac I gene (lac I+ on episome and lac I-on the bacterial chromosome)?

A. normal regulation of lactose metabolism
B. constitutive expression of lac Z+
C. inability to synthesize the lac Z+ gene product, à?-galactosidase
D. lac Z+ gene is inducible, but unable to be repressed by high glucose
E. no synthesis of the lac I gene product, the lac repressor

11. Bacteria utilize glucose first, even if other sugars are present, through a mechanism called:

A. operon repression
B. enzyme repression
C. catabolite repression
D. gene regulation
E. glucose utilization

12. An E. coli cell is grown in the presence of high amounts of glucose. Which of the following is true?

A. The cell will utilize lactose as a carbon source exclusively
B. The level of cyclic-AMP in the cell will be low
C. The level of cyclic-AMP in the cell will be high
D. Transcription of mRNA from the lac operon will be high
E. The cell will be forced to carry out fermentation

13. Which of the following growth media would you expect to result in synthesis of high levels of mRNA for the enzymes of the E. coli lac operon?

A. high glucose, high lactose
B. no glucose, no lactose
C. high glucose, low lactose
D. no glucose, high lactose
E. none of these

14. An E. coli cell is grown in the absence of glucose. Which of the following will be true?

A. The level of cyclic-AMP will be low
B. The CRP protein cannot bind to the DNA
C. If lactose is present, lac mRNA synthesis will occur at a high level
D. The cell will manufacture glucose by fixing carbon dioxide
E. The cell will be forced to carry out fermentation

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Solution Preview

1. Which of the following is not part of the lac operon of E. coli?

A. genes for inducible enzymes of lactose metabolism
B. genes for the repressor, a regulatory protein
C. gene for RNA polymerase
D. a promoter, the RNA polymerase binding site
E. the operator, the repressor binding site

2. (The role of the inducer of the lac operon). The inducer:

A. combines with a repressor and prevents it from binding to the promoter
B. combines with a repressor and prevents it from binding to the operator
C. binds to the promoter and prevents the repressor from binding to the operator
D. binds to the operator and prevents the repressor from binding at this site
E. binds to the termination codons and allows protein synthesis to continue

3. An E. coli strain is lac Z-. The structural gene for à?-galactosidase is encoded at the lac Z locus. How would you describe the regulation of lactose metabolism in these cells?

A. normal regulation of lactose metabolism
B. constitutive expression of lac Z+
C. inability to synthesize the lac Z+ gene product, à?-galactosidase
D. lac Z+ gene is inducible, but unable to be repressed by high glucose
E. no synthesis of the lac I gene product, the lac repressor

4. Cells of an E. coli strain that are trp- lac Z-met+bio+were mixed with cells of an E. coli strain that are trp+lac Z+ met- bio-and cultured for several hours. Then cells were removed, washed, and transferred to minimal media containing lactose as the only sugar source. A few cells were able to grow on minimal media with lactose, and formed colonies. How did these few cells become trp+ lac Z+ met+bio+?

A. transformation
B. ...

Solution Summary

This solution provides the correct answers for the multiple choice quiz on Molecular Genetics of Prokaryotes. An explanation for each correct answer is also provided.

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Genetics, Microbiology, and Cell Biology

Please help me understand the attached questions. I've placed them here, but you should open up the attachment to see them formatted better.

_________________________________________________

Multiple Choices: 1 point each (36 points total). Choose the single best answer for each of the following questions:

1. The accomplishments of Robert Koch include all the following except:
A. development of the rabies vaccine.
B. isolation of the tubercle bacillus.
C. isolation of the cholera bacillus.
D. proof of the germ theory of disease.

2. Pasteur's observations that protozoa were related to the silkworm disease strengthened his belief in the
A. germ theory of disease.
B. theory of spontaneous generation.
C. cell theory of animals and plants.
D. none of these.

3. During the Golden Age of Microbiology, mosquitoes and rat fleas were related to the transmission of
A. cholera, diphtheria and plague.
B. malaria, anthrax and tuberculosis.
C. plague, malaria and influenza.
D. syphilis, tetanus and diphtheria.
E. malaria, yellow fever and plague.

4. Robert Koch's postulates were set down to establish
A. a firm foundation for the germ theory of disease.
B. that spontaneous generation does not occur in nature.
C. that viruses are much smaller than bacteria.
D. that all living things are composed of cells.
E. the fact that DNA is the genetic information in all cells.

5. Spontaneous generation suggests that life can be formed from
A. preexisting life.
B. lifeless substances.
C. bacteria.
D. sperm and egg.

6. Anton van Leeuwenhoek is considered one of the first persons to describe
A. brain cells.
B. the development of the chick embryo.
C. bacteria.
D. the breathing system of insects.

7. Viruses consist essentially of
A. a mass of cellular cytoplasm with no membrane.
B. a chlorophyll-containing chloroplast surrounded by a cell wall.
C. a cell membrane enclosing a mass of carbohydrate.
D. a piece of nucleic acid surrounded by a protein coat.

8. Pasteur's experiments that disproved the theory of spontaneous generation used _________ to sterilize the broth:
A. alcohol
B. soap
C. disinfectant
D. heat

9. The bacteria in Pasteur's experiments that debunked the theory of spontaneous generation were coming from:
A. the nutrients provided
B. the agar used
C. the environment
D. the heat source

10. Which of the following sequences is listed from smallest to largest in size?
A. viruses, protozoa, bacteria
B. bacteria, viruses, fungi
C. fungi, protozoa, bacteria
D. viruses, bacteria, protozoa
E. bacteria, fungi, viruses

11. The binomial system of nomenclature for microorganisms utilizes
A. the genus and species.
B. the order and species.
C. the kingdom and genus names.
D. the family and order names.
E. the order and genus names.

12. All the following are characteristics of prokaryotes except
A. prokaryotes have organelles.
B. prokaryotes have ribosomes.
C. prokaryotes have no nucleus.
D. prokaryotes are surrounded by cell walls.

13. The correct way to write the name of a bacterium using Binomial nomenclature?
A. Escherichia Coli.
B. Escherichia coli.
C. Escherichia coli.
D. escherichia coli.

14. The modern classification system recognizes five kingdoms. Each of the following is one of these kingdoms, except
A. Fungi.
B. Eukaryota
C. Monera.
D. Protista.

15. Compared to eukaryotic cells, bacteria are
A. less complex
B. smaller
C. lower in chromosome number
D. all of the above

16. Viruses
A. are larger than bacteria
B. cannot multiply without a host cell
C. can be seen without a microscope
D. none of the above

17. The peptide bond is a type of covalent bond which forms
A. in a nucleic acid molecule.
B. only if ions are present.
C. between amino acids.
D. none of these

18. Nucleic acids are polymers of:
A. sugars
B. nucleic acids
C. ammonia
D. fatty acids
E. amino acids

19. Lipids are composed of:
A. fatty acids and glycerol
B. amino acids and glycerol
C. nucleic acids and glycerol
D. fatty acids and water
E. fatty acids and sugar

20. Phospholipids are used:
A. to form the membrane of the cell
B. to make proteins
C. to replenish amino acids
D. to organize the DNA of the cell

21. The two strands of DNA are held together by:
A. hydrogen bonds
B. covalent bonds
C. ionic bonds
D. peptide bonds

22. The plasma membrane of the cell is composed of how many layers of phospholipids:
A. 1
B. 2
C. 3
D. 4
E. 5

23. All the following are components of an RNA molecule except
A. cytosine.
B. ribose.
C. thymine.
D. uracil.
E. guanine.

24. Here is a given sequence of DNA: CGTTAGA. What would be the messenger RNA sequence which is complementary this DNA?
A. CTTTAGA.
B. GCAAUCU.
C. GCUUTCT.
D. CGAAUGU.
E. CUUUCCT.

25. The production of RNA using DNA as a template is known as
A. transduction.
B. transformation.
C. translation.
D. transcription.

26. The mechanism of DNA replication was shown by Meselson & Stahl to be:
A. semiconservative.
B. conservative.
C. random.
D. Sporadic.

27. How many nucleotides does it take to code for one single amino acid?
A. 1
B. 2
C. 3
D. 6

28. Which of the following is not a type of RNA encoded for by DNA?
A. messenger RNA
B. ribosomal RNA
C. transcription RNA
D. transfer RNA

29. The enzyme that synthesizes a single-stranded molecule of RNA complementary to DNA is:
A. RNA polymerase.
B. reverse transcriptase.
C. DNA ligase.
D. lysozyme.

30. Amino acids are polymerized into long chains during:
A. translation
B. replication
C. transcription
D. b and c

31. Which of the following involves codon:anticodon recognition:
A. DNA synthesis
B. protein synthesis
C. RNA synthesis
D. all of the above

32. The role of RNA polymerase
A. To synthesize a complementary strand of DNA using DNA as a template
B. To synthesize proteins by assembling amino acids together into chains
C. To synthesize a complementary strand of RNA using DNA as a template
D. To synthesize a complementary strand of RNA using RNA as a template

33. This process synthesizes a complementary copy of RNA using the enzyme RNA polymerase
A. translation
B. replication
C. transcription
D. b and c

34. The role of DNA Polymerase.
A. To synthesize a complementary strand of DNA using DNA as a template
B. To synthesize proteins by assembling amino acids together into chains
C. To synthesize a complementary strand of RNA using DNA as a template
D. To synthesize a complementary strand of RNA using RNA as a template

35. This process involves the complexing of mRNA with one or more ribosomes
A. translation
B. replication
C. transcription
D. b and c

36. The role of ribosomes:
A. To synthesize a complementary strand of DNA using DNA as a template
B. To synthesize proteins by assembling amino acids together into chains
C. To synthesize a complementary strand of RNA using DNA as a template
D. To synthesize a complementary strand of RNA using RNA as a template

Matching Section: Each question is worth 1 point. (24 points total)

Use the list of possible answers in the table below to match the word or phrase with its correct characteristic(s).

Matching Set 1: List of Possible Answers:
37. _____germ theory of disease A. van Leeuwenhoek's term
38. _____animalcules B. highly resistant bodies formed by some microbes
39. _____pasteurization C. Pasteur wrote about this idea
40. _____spores D. rapid discovery of basic principles
41. _____spontaneous generation E. life forms arise from decayed organic matter
42. _____Golden Age of Microbiology F. one infectious disease is produced by one organism

Select one of the following three choices for each of the options below:

Matching Set 2: List of Possible Answers:
43. ___Fungi A. Eukaryote
44. ___HIV B. Prokaryote
45. ___Animals C. Non-cellular
46. ___Bacteria Note: The above answers may be used more than once in this matching set.
47. ___Algae
48. ___Cells with organelles
49. ___Plants
50. ___Viruses

Match each word or phrase with its correct characteristic:

Matching Set 3: List of Possible Answers:
51. ___contains the genetic information for the cell A. fat
52. ___composed of chains of amino acids B. nucleotides
53. ___a type of lipid C. protein
54. ___subunits making up nucleic acids D. carbohydrate
55. ___includes starch and cellulose E. metabolism
56. ___sum of all biochemical processes taking place in a living cell F. nucleic acid

Match each antibiotic(s) with its function:

Matching Set 4: List of Possible Answers:
57. ___penicillin & cephlosporin A. inhibits cell wall synthesis
58. ___streptomycin & tetracycline B. inhibits nucleic acid synthesis
59. ___erythromycin & rifampin C. inhibits protein synthesis
60. ___polymyxin B D. inhibits function of cell membrane

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