Vector Biology and Gene Manipulation Questions and Answers Part-19

1. What are the plant host cells that contain T-DNA called?
a) Infected
b) Attacked
c) Transformed
d) Transfected

Answer: c
Explanation: When the T-DNA from Ti plasmid present inside the bacterial cell Agrobacterium tumefaciens is transferred to the chromosome of the plant host, the host cells are called transformed.

2. What are opines?.
a) Bacterial nutrients
b) Plant nutrients
c) Telomere sites
d) T-DNA ends

Answer: a
Explanation: The genes present on the T-DNA fragment direct the synthesis of unusual compounds called opines, that the bacteria use as nutrients.

3. What is the binary vector strategy used for?
a) Vector insertion into host
b) Insertion of new DNA
c) Manipulation of vector
d) Manipulation of host

Answer: b
Explanation: Due to the big size of Ti plasmid it is extremely difficult to find a unique restriction site. Novel strategies are hence used for the insertion of foreign DNA in the plasmid.

4. What is the basis of “binary vector” strategy?
a) No physical attachment
b) Big size
c) Strain dependence
d) Lysogenic/lytic cycle

Answer: a
Explanation: The binary vector strategy is based on the observation that the T-DNA does not need to be physically present/attached to the rest of the Ti plasmid.

5. In the binary vector strategy, the sizes of the two vectors used are _____ for bigger plasmid and ______ for smaller T-DNA plasmid.
a) 200, 20
b) 170, 20
c) 200, 50
d) 170, 50

Answer: b
Explanation: There are two vectors in the binary vector system. The bigger one is 170 kb in size and a smaller plasmid containing only the T-DNA region is 20 kb in size.

6. A two vector system contains a large normal vector and a small vector containing solely T-DNA fragment.
a) True
b) false

Answer: a
Explanation: A two vector system is basically constructed to surmount the problem of the big size of Ti plasmid. The basic principle is that no physical attachment of the plasmid with T-DNA is necessary.

7. The virulence region is contained in __________ of the binary vector system.
a) Large vector
b) Large vector along with specificity regions
c) Large vector along with restriction site
d) Small vector

Answer: b
Explanation: The virulence region and the host specificity region are contained in the larger plasmid and the T-DNA region along with a restriction site are contained in the smaller plasmid

8. The unique restriction sites in a “binary vector system” are located in _________
a) T-DNA
b) Telomere sequence
c) Large plasmid
d) Small plasmid

Answer: d
Explanation: The unique restriction sites are located within the T-DNA region on the smaller plasmid which is about 20 kb in size. The sites are required for manipulations.

9. Which vector does the co-integration strategy use?
a) E.coli vector
b) Bacteriophage
c) Bacterial plasmid
d) Ti plasmid

Answer: a
Explanation: The co-integration strategy is adapted to surmount the problem of the huge size of the Ti plasmid. In this strategy, E.coli vector is used that contains a part of T-DNA.

10. In which region does the infection of wound happen in crown gall disease?
a) Leaf
b) Root
c) Stem
d) Leaf node

Answer: c
Explanation: The infection of the wound happens in the stem, the bacteria attack the plant at the wounded stem portion and the process of transfer proceeds.