21. Which type of restriction enzymes does not usually require ATP?
A. Type I
B. Type II
C. Type III
D. Type IV
22. An example of a restriction fragment length polymorphism is
A. an Eco RI cuts DNA at a different sequence than Hind III
B. different length fragments of DNA resulting from loss or gain of a restriction site
C. cystic fibrosis results from a three base deletion in most cases but in other cases, other mutations are involved
D. all of the above
23. Knockout mice are created by
A. mutagenizing a mouse and selecting for mutant offspring
B. creating a chimera by fusing cells from two different cell lines
C. infecting the mouse with a retrovirus
D. transfecting embryonic stem cells with an altered gene sequence
24. A plasmid
A. is a circular DNA molecule
B. always contains an origin of replication
C. usually contains one or more restriction sites
D. all of the above
25. Under which of the following conditions would population gene frequencies remain the same?
A. Selection for homozygotes
B. Small population size
C. Active migration between groups
D. Random mating