51) “Bt cotton” refers to cotton that:

A) has been infested with insect pests.

B) is resistant to Bacillus thuringeniensis.

C) is resistant to herbicides.

D) is resistant to insect pests.

52) What is the advantage of genetically modifying crops such as corn, cotton, and potatoes with Bt genes?

A) to reduce the need for fertilizers

B) to stop Bacillus thuringiensis from damaging the crops

C) to improve the resistance of insect pests to Bt toxins

D) to make the crops more resistant to insect pests

53) One of the main problems with growing Bt cotton and other Bt-enhanced crops is the Bt toxin:

A) can produce populations of insects resistant to it.

B) can create Bt refuges near the fields that harbor bugs not resistant to Bt.

C) reduces the need for insecticides.

D) can be harmful to humans.

54) The enzyme EcoRI cuts between the G and the A in the sequence GAATTC. The enzyme BamHI cuts between adjacent G nucleotides in the sequence GGATCC. The sticky ends that are generated by the two enzymes are complementary and will stick together.

55) Restriction enzymes occur naturally in bacteria.

56) It is not possible for a human gene to work in any other organism.

57) A human clone would be as much like the person from whom it was cloned as “identical” twins are like each other.

58) Reproductive cloning has been used to clone humans.

59) Forensic DNA typing can prove the innocence of a crime suspect.