MCQ-4

16. If a recombinant DNA bearing gene for ampicillin resistance is transferred into E. Coli cells and the host cells are spread on agar plates containing amplicillin,then

a)  Both transformed and untransformed recipient cells will die

b)  Both transformed and untransformed recipient cells will grow

c)  transformed recipient cells will grow and untransformed recipient cells will die

d)  transformed recipient cells will die and untransformed recipient cells will grow

17. The figure below shows three steps (A,B,C) of polymerase chain reaction (PCR). Select the option giving correct identification together with what it represent?

       

a)  B- denaturation at a temperature of about 98  separating the two DNA strands.

b)  A- denaturation at a temperature of about 50

c)  C- extension in the presence of heat stable DNA polymerase.

d)  A- annealing with two sets of Primers

18. Identify the DNA segment which is not a palindromic sequence

a)  5'GGATCC3'

3'GGTACC5'

b)  5'GAATTC3'

3'CTTAAG5'

c)  5'GCGGCCGC3'

3'CGCCGGCG5'

d)  5'CCCGGG3'

3'GGGCCC5'

19. Electroporation involves

a)  Promotion of seed germination by induced imbibition of water with electric current.

b)  Making transient pores in cell membrane to facilitate entry to  gene constructs.

c)  Purification of saline water with the help of an artificial membrane

d)  Passage of sucrose unrough sieve pores by electroosmosis.

20. In pBR322, the gene sequence of the codes for the proteins involved in the  replication of the plasmid is

a)  Pvu II

b)  Cla I

c)  rop

d)  Pst I

Explanation:

16.    Ans:C

Transformation is a procedure through which a piece of DNA is introduced in a host bacterium. DNA bearing ampicillin resistant gene (transformed recipient cells) when introduced into the plate containing ampicillin will grow while DNA not bearing ampicillin resistance gene(untransformed recipient cells) will die.

17.  Ans:A

A Schematic representation of PCR can be illustrated as follows:

18.  Ans :A

19.  Ans :B

Electroporation is the method of vectorless gene transfer in which the electrical impulses induce transient porse in the plant cell membrane. Through this pore DNA molecules are incorporated into the plant cells.

20.  Ans:C

pBR322 is a plasmid vector widely used in gene cloning experiments.The gene sequence 'rop' codes for the proteins involved in DNA replication.