Multiple Choice Questions
1. DNA cloning: the basics Page: 307 Difficulty: 1 Ans: C Restriction enzymes:
A) act at the membrane to restrict the passage of certain molecules into the cell. B) are highly specialized ribonucleases that degrade mRNA soon after its synthesis. C) are sequence-specific DNA endonucleases. D) are very specific proteases that cleave peptides at only certain sequences. E) catalyze the addition of a certain amino acid to a specific tRNA.
2. DNA cloning: the basics Pages: 307-308 Difficulty: 2 Ans: B The biological role of restriction enzymes is to:
A) aid recombinant DNA research. B) degrade foreign DNA that enters a bacterium. C) make bacteria resistant to antibiotics. D) restrict the damage to DNA by ultraviolet light. E) restrict the size of DNA in certain bacteria.
3. DNA cloning: the basics Page: 308 Difficulty: 1 Ans: A The size of the DNA region specifically recognized by type II restriction enzymes is typically:
A) 4 to 6 base pairs. B) 10 to 15 base pairs. C) 50 to 60 base pairs. D) 200 to 300 base pairs. E) about the size of an average gene.
4. DNA cloning: the basics Page: 308 Difficulty: 2 Ans: D Which of the following statements about type II restriction enzymes is false?
A) Many make staggered (off-center) cuts within their recognition sequences. B) Some cut DNA to generate blunt ends. C) They are part of a bacterial defense system in which foreign DNA is cleaved. D) They cleave and ligate DNA. E) They cleave DNA only at recognition sequences specific to a given restriction enzyme.
5. DNA cloning: the basics Page: 308 Difficulty: 2 Ans: C Certain restriction enzymes produce cohesive (sticky) ends. This means that they:
A) cut both DNA strands at the same base pair. B) cut in regions of high