21. EMBL 3 and EMBL 4 are replacement vectors, which can clone DNA up to
A. 6-7 kb
B. 15-25 kb
C. 40-44 kb
D. 1-2 kb
22. Size of the DNA that can be packaged into a λ phage is
A. 50 kb
B. 35-53 kb
C. 40-50 kb
D. any size
23. Charon 34 and Charon 35 are the examples of
A. plasmid vector
B. cosmid vector
C. phage vector
D. phagemid vector
24. Cosmid vectors are used for
A. cloning small fragments of DNA
B. cloning large fragments of DNA
C. cloning prokaryotic DNA only
D. cloning eukaryotic DNA only
25. Plasmids which are maintained as a limited number of copies per cell are known as
A. stringent plasmids
B. relaxed plasmids
C. cryptic plasmids
D. all of these