Which statement about bacteriophages is True?
Anonymous Quiz
65%
They may be used to introduce foreign DNA into a host cell
5%
All bacteria are equally susceptible to different phages
3%
The nucleic acid core is usually RNA
27%
The lytic cyde starts by adsorption of the phage head to the bacterial cell
In lytic cycle of bacteriophage All the following occur EXCEPT
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3%
The phage attaches by its tail to a specific receptor
3%
The tail sheath tracts & nucleic acid is injected into the cell
82%
The prophage is carried inside the bacterial cell indefinitely passing to daughter cell
12%
The phage components aggregate to form complete phage particles
The lysogenic bacterial cell is the cell containing:
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0%
Lysosomes
8%
Bacteriocins
90%
Prophage
3%
Lysozymes
0%
Plasmids
Lysogenic conversion is caused by
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92%
Prophage DNA
5%
Lytic bacteriophage
3%
Lysozymes
0%
Transposons
During lysogenic cycle, the bacteriophage
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24%
Remains silent in the host cell
6%
Allows replication of other viruses in the host cell
3%
Deletes all the bacterial properties and expresses the phage properties.
68%
Expresses properties encoded by the prophage
Bacteria containing prophage are called:
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0%
Lytic bacteria
89%
Lysogenic bacteria
3%
Lytic bacteriophages
8%
Lysogenic bacteriophages
Bacteriophage typing is used for:
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21%
Serological identification of baderia
7%
Isolation of bacteria from clinical specimens
34%
Tracing the source of infection outbreak
38%
in vitro susceptibility testing to antimicrobial agents
Which event occurs SOLELY in a temperate bacteriophage cycle
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14%
Generalized transduction
9%
Intracellular synthesis of phage components
5%
Lysis of the bacterial cell
73%
Lysogenic conversion
Genetic information in bacteria is carried on the following EXCEPT:
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63%
Ribosomes
23%
Transposons
7%
Plasmids
3%
Chromosome
3%
Prophage DNA
All the following about plasmids are true EXCEPT
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16%
Double stranded DNA molecules
74%
Replicate dependably on the bacterial chromosome
6%
Their length is about 1:50 of bacterial chromosome
3%
They may carry resistance genes.
All the followings are true about plasmids EXCEPT
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7%
They are capable of replicating independently.
3%
They are transferable from one bacterium to another by conjugation
80%
Relaxed-plasmids are usually large and present in few copies
10%
They may code for bacteriocin, exotoxins, and adhesins
Plasmids differ from transposable genetic elements, as plasmids:
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7%
Become inserted into chromosomes
79%
Are self-replicating outside the chromosome
11%
Carry genes for virulence (e.g. exotoxin production)
4%
Carry genes for antibiotic resistance
All the following are true for plasmids EXCEPT:
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3%
They are small circular molecules of DNA
0%
They may encode genes that enhance pathogenicity of the organism
0%
They may contain antibiotic resistance genes
97%
They are essential for survival of organisms in most situations
Plasmids may code for any of the following EXCEPT:
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0%
Sex pilus formation
94%
Growth
3%
Antibiotic resistance
0%
Virulence
3%
Bacteriocin production
Relaxed plasmids are characterized by:
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21%
Few copy number
29%
Replicate in absence of protein synthesis
11%
Large size
39%
Being usually conjugative
Conjugative plasmids:
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4%
Are usually small in size
96%
Carry fertility (F) factor
0%
Are relaxed plasmids
0%
Have a large copy number.
Regarding plasmids, which statement is True:
Anonymous Quiz
84%
They are extrachromosomal, double stranded DNA molecules
6%
They are much larger than the bacterial chromosome.
6%
They are non-replicating transferable DNA segments.
3%
They encode properties that are essential for bacterial growth
Which statement is CORRECT Concerning conjugative plasmids
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0%
Their copy number is above 30
3%
They are common in Gram-positive cocci
8%
They are usually small in size
90%
They carry the F factors.