Bacteriophages 3

Previous exams & Formative:

1- The genome of bacteriophage can be: a. DNA only b. Both DNA and RNA c. Either DNA or RNA d. RNA only

2- Bacteriophage responsible for lysogenic cycle is called: a. Temperate phage b. Virulent phage c. Lytic phage d. None of the above a. It is caused by lytic phage. b. The phage does not insert itself in the bacterial chromosome. c. Specialized transduction occurs as an error of the temperate phage from the bacterial chromosome. d. Specialized transduction occurs as an error in assembly.

3- Which of the following is true about the lysogenic phage cycle?

4- About the lytic cycle, select one: a. The phage is said to be virulent. b. The phage is known as temperate phage. c. The phage DNA is inserted into the bacterial chromosome. d. Ends by bacterial cell replication.

5- The virulence factor that acquired by lysogenic conversion is encoded by the DNA of: a. Conjugative plasmid b. Lytic phage c. Temperate phage d. Integron

6- The error that occurs during the assembly phase of bacterial phage replication and that leads to incorporation of part of bacterial DNA into the phage particle is termed as: a. Transformation b. Generalized transduction. c. Transposition d. Specialized transduction e. Conjugation

1-c 2-a 3-c 4-a 5-c 6-b

Extra:

1- Lysogenized bacterial cell is the cell containing: a. Inclusion bodies b. Bacteriocins c. Endopigments d. Prophage

2- Host specificity of the phage is usually determined by: a. Type of enzyme that the phage has b. Type of nucleic acid in the head c. Shape of the capsid d. The tail e. Contractile sheath

3- The generalized transduction is a process of gene transfer when: a. Free DNA is transferred to bacteria. b. Transfer of any segment of donor DNA randomly by bacteriophage. c. A specific bacteriophage transduces only a particular gene. d. Transfer by sex factor. e. Transfer by temperate phage

4- Bacteriophages are: a. Bacteria attack viruses b. Viruses attack bacteria c. Free living viruses d. All of the above

5- Bacteriophage undergoes replication by: a. Binary fission and fragmentation b. Lytic and lysogenic cycles c. Both d. None

6- The order of lytic cycle is: a. Adsorption-Injection of genetic material-maturation-biosynthesis-lysis and release. b. Adsorption-Injection of genetic material- prophage. c. Adsorption-Injection of genetic material-biosynthesis- maturation- lysis and release. d. Adsorption- Injection of genetic material- lysis

7- The viral genome integrated to the bacterial genome is called: a. Plasmid b. Prophage c. Virion d. Capsid

8- Lysogenic strains are also called: a. Temperate phages b. Avirulent phages c. Both a & b d. None of the above

Previous exams & Formative:

1. A small circular double stranded DNA that is capable of autonomous replication is called: a. Bacterial chromosome b. Transpose c. Phage d. Pathogenicity island e. Plasmid

2. The error that occurs during the assembly phase of bacterial phage replication and that leads to incorporation of part of bacterial DNA into phage particle is termed: a. Transformation b. Generalized transduction c. Transposition d. Specialized transduction e. Conjugation

3. Uptake by recipient cell of soluble DNA released from a donor cell is defined as: a. Conjugation b. Recombination c. Competence d. Transformation e. Transduction

4. All of the following are methods of gene transfer from one bacterial cell to another except a. Conjugation b. Mutation c. Transformation d. Generalized transduction

5. All the following is true about plasmids except: a. They are circular molecules b. They are double stranded c. They are capable of autonomous replication d. They cannot move from one bacterial strain to another

6. Which of the following is true about lysogenic phage cycle: a. It is caused by lytic phage b. The phage doesn't insert itself in the bacterial chromosome c. Specialized transduction occurs as an error in excision of the temperate phage from the bacterial chromosome d. Specialized transduction occur as an error in assembly

7. All genetic material of bacteria is composed of: a. Single linear bacterial chromosome only b. Single circular bacterial chromosome only c. Single circular bacterial chromosome and extra-chromosomal elements d. Plasmids and phages only

8. A process that allows defective viruses to replicate and spread is called: a. Recombination b. Reassortment c. Complementation d. Interference

9. Bacterial chromosome is composed of: a. Double stranded DNA b. Double stranded RNA c. Single stranded DNA d. Single stranded RNA

10. Which of the following is not true regarding criteria of good cloning vector: a. It should be small in size b. It should be capable of autonomous replication c. It should be well characterized regarding restriction endonuclease cleavage site d. It should have a wide host range

11. Direct transfer of a plasmid between two bacteria is defined as a. Conjugation b. Recombination c. Competence d. Transformation e. Transduction

12. Mutations that can multiply under some conditions but not under other conditions are: a. Plaque-size mutants b. Conditional-lethal mutants c. Host-range mutants d. Drug-resistant mutant

1. Plasmid is a: a. Plasma protein b. Cytoplasmic granules c. Genetic factor d. Part of plasma membrane e. Serum factor

2. The transfer of specific parts of bacterial DNA to another bacteria cell can be mediated by: a. Transformation b. Specialized transduction c. Conjugation d. Generalized transduction e. Recombination

3. Plasmids that can mediate gene transfer by conjugation are Known as: a. F factor b. Conjugative transposon c. R factor d. Cosmid e. Col factor a. Conjugation resulting in transfer of an R factor b. Transposition of a mobile genetic element c. Integration of a temperate bacteriophage d. Transduction of a chromosomal gene e. Recombination of a homologous genetic element

4. Which one of the following processes involves a sex pilus?

5. A form of genetic transfer in which donor DNA is introduced in the recipient by a bacterial virus: a. Conjugation b. Transduction c. Vertical gene transfer d. Transcription e. Transformation

6. Plasmid could be transmitted to other bacteria in: a. Transformation b. Generalized transduction c. Conjugation d. Specialized transduction e. Fusion

7. The mode of transfer in which naked DNA is directly taken by the recipient cell is known as: a. Transformation b. Cell transmission c. Transduction d. Cell fusion

8. Drug resistance in bacteria is mainly determined by: a. F factor b. R factor c. Col factor d. Lysogenic factor

9. Genetic information essential for bacterial life is a function of: a. Plasmid b. Chromosome c. Mesosomes d. Ribosome

10. Plasmid governs the following functions in bacteria EXCEPT: a. Drug resistance b. Bacteriocin production c. Virulence d. Production of endotoxin e. Production of capsule

11. Heritable changes in genome are called: a. Conjugation b. Mutation c. Transduction d. Replication

12. Transformation is a process of gene transfer in bacteria. It involves: a. Taking up of DNA from the environment b. Transfer of DNA from mother cell to its progeny c. Transfer of genes between bacteria during cell contact d. Transfer of genes from bacterial viruses to bacterial cell e. Transfer of genes from plasmid to chromosome

13. The transfer of a portion of the DNA from one bacterium to another by bacteriophage is known as: a. Transcription b. Complementation c. Transduction d. Conjugation

14. The generalized transduction is a process of gene transfer when: a. Free DNA is transferred to bacteria b. Transfer any segment of donor DNA at random by bacteriophage c. A specific bacteriophage transduces only a particular gene d. Transfer by sex factor e. Transfer by temperate phage

15. All the following is true about plasmids except: a. They are circular molecules b. They are double stranded c. They are capable of autonomous replication d. They cannot move from one bacterial strain to another

16. Extra-chromosomal double stranded DNA that is capable of autonomous replication is: a. Bacterial chromosome b. Plasmid c. Bacteriophage d. None of the above

17. If a base replaces by another base pair sequence the mutation the resulting replacement is known as a. Alternation b. Substitution c. Missense d. Nonsense

18. When one or more base pair are deleted or added in the sequence shifts the reading frame on the ribosome called a. Substitution mutation b. Missense mutation c. Nonsense mutation d. Frameshift mutation a. True b. False

19. Transfer of genes between cells that are in physical contact with one another is known as transformation.

Previous exams & Formative:

1- Selective toxicity: a. Is the ability of an antimicrobial agent to protect a pathogen without harming the host. b. Is the ability of an antimicrobial agent to harm a pathogen with harming the host. c. Is the ability of an antimicrobial agent to harm a pathogen without harming the host. d. Is the ability of an antimicrobial agent to harm the pathogen and the host.

2- Which of the following is the Complication of antimicrobial chemotherapy a. Hypersensitivity b. Emergence of resistant mutants. c. Toxicity d. All of the above

3- All of the following are Mechanisms of action of antimicrobial agents except a. Inhibition of bacterial protein synthesis b. Inhibition of bacterial nucleic acid synthesis c. Reduction of the intracellular concentration of the antibiotic d. Interference with the cell membrane function

4- PABA (para-aminobenzoic acid) is important in bacteria for a. Synthesis of folic acid b. Molecularly similar to Cephalosporins c. A substrate used in the production of sulphonamides d. Synthesis of bacterial cell wall

5- The most selective antibacterial agents are those that interfere with bacterial cell wall synthesis. This is because a. Eukaryotic cells inactivate the drugs before they can do any damage b. Eukaryotic cells do not take up the drugs c. Bacterial cell walls have a unique structure not found in eukaryotic host cells d. Bacterial cell wall synthesis is easily inhibited whereas eukaryotic cell wall synthesis is more resistant to the actions of the drugs

6- The mechanism of action of Aminoglycoside antibiotics is to: a. Inhibit cell wall synthesis b. Bind to bacterial DNA polymerase c. Inhibit folic acid biosynthesis d. Bind to the 30s ribosomal subunit a. Inhibition of cell wall synthesis b. Damage to cytoplasmic membrane c. Inhibition of nucleic acid synthesis d. Inhibition of specific enzyme systems e. Inhibition of protein synthesis

7- Chloramphenicol inhibits the growth of the microbes by carrying out which of the following actions?

8- The antimicrobial action is through inhibition of cell wall synthesis for all of the following drugs EXCEPT: a. Cephalosporins b. Cycloserine c. Penicillins d. Vancomycin e. Aminoglycosides

9- Resistance to Penicillin and other B lactams is due to a. Modification of target pbps b. Impaired penetration of drug to target pbps c. Presence of an efflux pump d. Inactivation of antibiotics by B lactamase e. All of the above a. Penicillin b. Chloramphenicol c. Trimethoprim d. Tetracycline e. Sulfonamides

10- Which one of the following antibiotics inhibits dihydrofolate reductase?

11- All of the followings are considered mechanism of action of antibiotic except: a. Inhibition of bacterial cell wall synthesis b. Interference with the cell membrane function c. Modification of the target site for the antibiotic d. Inhibition of bacterial nucleic acid synthesis

12- B-lactam antibiotics: e.g., penicillins, cephalosporins, carbapenems and monobactams: a. Inhibit the last steps of peptidoglycan synthesis b. Inhibit early steps of peptidoglycan synthesis c. Inhibit the Intermediate steps of peptidoglycan synthesis d. All of above

13- B-lactam antibiotics: e.g., penicillins and cephalosporins act by: a. Interference with the cell membrane function b. Inhibition of bacterial cell wall synthesis c. Inhibition of bacterial protein synthesis d. Inhibition of bacterial nucleic acid synthesis a. Lipopolysaccharide b. Cellulose c. Peptidoglycan d. Proteins e. Teichoic acid a. Streptomycin b. Tetracycline c. Chloramphenicol d. Penicillin e. Vancomycin a. Inhibition of cell-wall synthesis b. Damage to cytoplasmic membrane c. Inhibition of nucleic acid d. Inhibition of specific enzyme systems e. Inhibition of protein synthesis

14- Cell wall biosynthesis is inhibited by antibiotics by inhibiting the biosynthesis of which of the following?

15- Which of the following inhibits protein synthesis by combining with the 50S subunit ribosome?

16- Polymyxins inhibit the growth of the microbes by carrying out which of the following actions?

17- All of the following are B-Lactam antibiotics except a. Vancomycin b. Benzylpenicillin c. Cephalosporin d. Monobactam e. Carbapenems a. It inhibits dihydrofolate reductase. b. It inhibits DNA- dependent RNA polymerase. c. It inhibits protein synthesis by binding to the 30s ribosomal subunit. d. It inhibits protein synthesis by binding to the 50s ribosomal subunit. e. It inhibits DNA gyrase. a. Penicillins b. Polymyxins c. Quinolones d. Chloramphenicol e. Cephalosporins a. RNA polymerase b. Reverse transcriptase c. Penicillin-binding proteins (pbps) d. DNA gyrase e. Restriction endonuclease

18- A hospitalized patient develops dysuria and suprapubic pain and is treated with a quinolone. What is the mechanism of action of this antibiotic?

19- Inhibitors of DNA synthesis include which of the followings?

20- Certain enzymes catalyze the cross-linking of peptidoglycan, a unique constituent of bacterial cell walls. Which of the following may be a factor in antibiotic resistance, the target of which is cell-wall synthesis?