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Ch 12 Quiz
1. Under what circumstances would a geneticist use PCR? (1)
To amplify DNA- make more
2. How does reverse transcriptase make a single strand of DNA from a mRNA (2)?
Reverse transcriptase creates DNA from mRNA by first isolating the mRNA, adding
reverse transcriptase, which creates a complimentary strand of DNA- single stranded,
then DNA polymerase adds the second complimentary strand
3. How is recombinant DNA created in a bacterium plasmid? (2)
A gene of interest is identified. The plasmid and gene of interest are both cut with the
same restriction enzyme. The gene is then inserted into the bacteria and DNA ligase
binds the two fragments together
4. Restriction enzymes (1)
A) edit proteins.
B) cut DNA at specific sites.
C) stop transcription.
D) bind together strands of DNA.
E) bind RNA fragments together.
5. Label the positive and negative ends of the electrophoresis gel and place the DNA
segments for each clone number in order from smallest to largest. (2)
Negative end is at the top, positive at the bottom. Ordered from smallest to largest: 18,
19, 23, 22, 26, 25, 21, 24, 20
6. How can single nucleotide polymorphisms (SNP’s) lead to differences in DNA
fragments after being cut with restriction enzymes? (1)
SNP’s can alter the site at which the restriction enzyme is being cut, preventing the
enzyme from cutting there. If the enzyme cannot cut the DNA there, the result will be a
longer piece of DNA
7. DNA fragments that have matching sticky ends are joined by covalent bonds formed
by the action of (1)
A) DNA ligase.
B) DNA polymerase.
C) DNA helicase.
D) covalentase.
E) a restriction enzyme.