IMAT 2013 Q31 [Transcription]

The direct product of transcription of recombinant DNA can be:

A. insulin.
B. monoclonal antibodies.
C. mRNA.
D. the primary structure of a protein.
E. a replicate DNA molecule.

The answer to this question is choice C.

This is a fairly straightforward question to answer, but do not get confused by the term “recombinant” (which is a term used to describe recombined DNA sequences under laboratory intervention). This question can be approached systematically:

  1. The question is asking for the direct product of transcription, thus your answer should be the direct result after RNA polymerase has acted on the DNA template. You can then approach each choice to see if they satisfy this condition.
  2. Choice A, insulin, is a hormone that has undergone various posttranslational modifications. Even its precursor, preproinsulin, is a protein, which is NOT a product of transcription, but translation. Thus, remove this from your consideration.
  3. The next choice, which are antibodies, are again made up of polypeptides, which does NOT make it a direct product of transcription. With this in mind, you can also eliminate choice D in your considerations.
  4. The next choice, which is mRNA, is the correct answer, since it is the direct product of transcription, due to the action of RNA polymerase.
  5. To other choice, which is “a replicate DNA molecule” is logically not the correct answer, since this would be the direct product of the process of replication mediated by DNA polymerases, and not the product of transcription.

Thus, the correct answer is choice C, mRNA.