Vector Biology Multiple Choice Questions on “Vectors and Cloning in Gram – Positive Bacteria – 1”.
1. In Gram-positive bacteria, there is a disparity in ___________ in the genomes.
A. AT content
B. GC content
A. Structure
D. Composition
Answer: B
Clarification: In Gram-positive bacteria, the base composition of the different genomes ranges from less than 30 percent to more than 70 percent.
2. There are no universal cloning vectors for use with all Gram-positive bacteria.
A. True
B. False
Answer: A
Clarification: Given the disparity in GC content, the base composition of the different genomes ranges from less than 30 percent to more than 70 percent.
3. Streptomycetes are ______________
A. High GC content
B. Low GC content
A. Gram-negative bacteria
D. Low AT content
Answer: A
Clarification: There are no universal cloning vehicles for use with all Gram-positive bacteria. One set of systems has been developed for high-GC organisms such as Streptomycetes and another for low-GC organisms.
4. Which of the following is not a lactic acid producing bacteria?
A. Streptococcus
B. Lactococcus
A. Lactobacillus
D. Clostridium
Answer: D
Clarification: The latter group comprises bacteria from unrelated genera Bacillus, Clostridium and lactic acid producing bacteria lactococcus, streptococcus, lactobacillus.
5. Bacillus subtilis is a _________ bacteria.
A. Gram-negative
B. Low-GC
A. High-GC
D. High-AT
Answer: B
Clarification: Many of the cloning vectors used with Bacillus Subtilis and other low-GC bacteria are derived from plasmids found in Staphylococcus aureus.
6. Cloning vectors for low-GC bacteria are derived from ________
A. Plasmids
B. Yeasts
A. Plants
D. Mammals
Answer: A
Clarification: Many of the cloning vectors used with Bacillus Subtilis and other low-GC bacteria are derived from plasmids found in Staphylococcus aureus.
7. Plasmids from S. aureus transform into B. subtilis and express _____________ normally.
A. Lactic acid
B. Antibiotic resistance
A. Antibiotics
D. Crown gall
Answer: B
Clarification: Plasmids from S.aureus can be transformed into B.subtilis, where they replicate and express antibiotic resistance normally.
8. S. aureus plasmids carry ______ selectable markers.
A. More than one
B. One
A. No
D. Two
Answer: B
Clarification: None of the S. aureus plasmids carries more than one selectable marker and so improved vectors have been constructed by gene manipulation.
9. Vector PC194 carries ____ gene of PT127.
A. TCR
B. PCR
A. CCR
D. GCR
Answer: A
Clarification: Improved vectors have been constructed by gene manipulation.
For example, pHV11 is PC194 carrying the TCR gene of pT127.
10. Which of the following is greatly reduced in plasmid vectors post insertion of exogenous DNA?
A. Size
B. Stability
A. Infection
D. Efficiency
Answer: B
Clarification: In general, plasmids are stable in Bacillus subtilis, but segregative stability is greatly reduced following insertion of exogenous DNA.
11. Which of the following is a cryptic Bacillus plasmid?
A. Pta1060
B. Pta1100
A. Pta 10
D. BSA
Answer: A
Clarification: Stable host-vector systems in B.subtilis are more likely if endogenous plasmids are used. Bron and colleagues have developed the cryptic Bacillus plasmid.
12. Hybrid vectors can replicate both in ________ and B. subtilis.
A. Mammals
B. Insects
A. Plants
D. E.coli
Answer: D
Clarification: Because of difficulties experienced in direct cloning in B.subtilis, hybrid plasmids were constructed which can replicate in both E.coli and B. subtilis.
13. Which of the following is not a filamentous coliphage vector?
A. M13
B. Lambda
A. F1
D. Fd
Answer: B
Clarification: M13, F1, FD are filamentous coliphages containing a circular single-stranded DNA molecule. These have been developed as vectors because of various advantages.
14. Coliphages are single-stranded vectors.
A. True
B. False
Answer: A
Clarification: M13, F1, FD are filamentous coliphages containing a circular single-stranded DNA molecule. These have been developed as vectors because of various advantages.
15. What is the average size of single-stranded vector?
A. 6400 nucleotides
B. 1200 nucleotides
A. 2500 nucleotides
D. 5500 nucleotides
Answer: A
Clarification: The phage particles have dimensions 900*9 nm and contain a single-stranded circular DNA molecule, which is 6407 (M13) or 6408 (fD).