When DNA Probes Are Used to Identify Bacterial DNA Similarities

question 39

Multiple Choice

When DNA probes are used to identify bacterial DNA similarities by hybridization, the probe DNA is heated and the template DNA is treated to separate the 2 strands. Why would the probe DNA be heated?

• A) This is the only way to properly label the probe DNA.
• B) The probe DNA is single-stranded, but it may have folded back on itself and formed portions that are double-stranded. Heating it up breaks any possible hydrogen bonds that may have formed, returning it to a single-stranded state prior to hybridization.
• C) Heating it up activates the tag on the probe DNA before it hybridizes to the bacterial template DNA.
• D) DNA hybridization can only take place at high temperatures, so all the DNA must be heated up prior to hybridization.