16. For gene probes to be useful they must

A. be large enough to contain gene-specific sequences
B. be labeled in some manner to allow detection
C. both (a) and (b)
D. none of the above

17. A genomic library is

A. a database where the sequence of an organism’s genome is stored
B. a collection of many clones possessing different DNA fragments from the same organisms bound to vectors
C. a book that describes how to isolate DNA from a particular organism
D. a place where the information of the genetic organization of organisms are kept.

18. Which of the following enzyme is used to covalently bond foreign DNA to a vector plasmid?

A. DNA polymerase
B. Restriction endonuclease
C. DNA ligase
D. DNA helicase

19. Bacterial cells protect their own DNA from degradation by restriction endonucleases by

A. methylating the DNA at the sites that the enzyme recognizes
B. deleting all recognition sites from the genome
C. not producing any restriction endonucleases
D. having anti restriction endonucleases

20. Which type of restriction endonuclease cuts the DNA within the recognition site?

A. Type I
B. Type II
C. Type III
D. All of these