21. Opines that are present in crown gall tumor include
A. octopine
B. nopaline
C. agropine
D. all of these
22. Intermediate vectors containing T-DNA are conjugation deficient. Thus conjugation is mediated in presence of which of the following plasmid?
A. pRK 2013
B. pRN 3
C. either (a) or (b)
D. none of these
23. Which of the following is true about T DNA?
A. Integration of T DNA can occur at many different, apparently random, sites in the plant nuclear DNA
B. Integration of T DNA occurs only at one specific site in the plant nuclear DNA
C. Integration of T DNA occurs at two specific sites in the plant nuclear DNA
D. Integration of T DNA occurs at one site that may be random in the plant nuclear DNA
24. Which of the following is not true about the direct repeats flanking T-DNA?
A. They are conserved between nopaline and octopine Ti-plasmids
B. These repeats are transferred intact to the plant genome
C. These are important in the integration mechanism
D. all of the above
25. The left segment of octopine T-DNA (TL) is necessary for
A. enzymes for agropine biosynthesis
B. tumor formation
C. conjugative transfer
D. all of these