| 1. | endonuclease | 2. | exonuclease | 
| 3. | ligase | 4. | polymerase | 
| I: | Herbert Boyer performed studies on a couple of restriction enzymes of the E.coli bacterium with especially useful properties. | 
| II: | Stanley Cohen developed a method of removing plasmids from the bacterial cell and then reinserting them in other bacterial cells. | 
| 1. | allows selection of transformants | 
| 2. | promotes uptake of DNA through membrane transport proteins | 
| 3. | creates pores in the bacterial plasma membrane and allows plasmid DNA to enter the bacterial DNA. | 
| 4. | coagulates DNA in the bacterial cell. | 
Which of the following is not required in the preparation of a recombinant DNA molecule?
| 1. | Restriction endonuclease | 2. | DNA ligase | 
| 3. | DNA fragments | 4. | E.coli | 
| 1. | It increases the DNA’s mobility through the gel. | 
| 2. | It condenses the DNA to allow it to enter the gel. | 
| 3. | It fluoresces under UV light, allowing visualization of DNA bands. | 
| 4. | It cleaves DNA at specific bases, allowing it to be visualized. | 
The advantage of using DNA polymerases from thermophilic organisms in PCR is that:
| 1. | the DNA polymerases of these bacteria are much faster than those from other organisms | 
| 2. | the DNA polymerases of these bacteria can withstand the high temperatures needed to denature the DNA strands | 
| 3. | the DNA polymerases of these bacteria never make mistakes while replicating DNA | 
| 4. | all of the above | 
The chronological steps of a polymerase chain reaction are:
| 1. | Denaturation, Annealing of primers, Primer extension | 
| 2. | Annealing of primers, Denaturation, Primer extension | 
| 3. | Annealing of primers, Primer extension, Denaturation | 
| 4. | Denaturation, Primer extension, Annealing of primers |