PROBLEM SET 7: Recombinant DNA technology
1) The PCR reaction mixture does not include:
A)
B)
C)
D)
E)
all four deoxynucleoside triphosphates.
DNA containing the sequence to be amplified.
DNA ligase.
heat-stable DNA polymerase.
oligonucleotide primer(s).
Ans: C
2) A DNA sequence that may be present as only a single copy in a large mammalian genome
can be amplified and cloned using the polymerase chain reaction (PCR). Describe the steps
and reaction components required in a PCR experiment. Illustrate the steps in just one round.
Ans: DNA with the desired sequence is heated to convert it to single strands and cooled in
the presence of an excess of oligonucleotide primers that flank the sequence to be amplified.
A heat-stable DNA polymerase extends the primers, replicating the desired sequence. (See
Fig. 9-16.)
3) What are RFLPs and how are they used in forensic DNA fingerprinting technology?
Ans: RFLPs (restriction fragment length polymorphisms) are minor variations among
individuals in DNA base sequence that can be detected by variation in the patterns of
fragments that are produced upon cleavage with restriction endonucleases. When several
DNA regions are examined, these patterns are distinctive for an individual and can be used to
determine the identity (or nonidentity) of two samples of DNA. One of these samples can be
from a crime scene, the other from a known individual.