Question

AP Biology (a) Explain why an mRNA transcribed from the template strand of the SIRT3 gene in normal stomach ( NS ) cells is translated to produce a SIRT3 protein of correct sequence, but if an mRNA were transcribed from the nontemplate strand of the SIRT3 gene in these cells, it would not produce a SIRT3 protein of correct sequence.

Answer 1

Answer:

The nontemplate strand of the SIRT3 gene would encode an mRNA with a sequence complementary to the SIRT3 transcript

Explanation:

Within the cell nucleus, the RNA Polymerase II (RNAPII) binds to the non-coding DNA strand in order to transcribe a precursor messenger RNA (pre-mRNA) sequence that is directly complementary to the target DNA region (with the exception of Uracil instead of Thymine). This pre-mRNA is then processed to form mature mRNA. The coding DNA strand is the DNA strand whose base sequence is identical to the mRNA synthesized, thereby the nontemplate strand is referred to as the coding strand. Subsequently, mRNA leaves the cell nucleus and travels to the ribosome in the cytoplasm, which uses this information to be translated into the corresponding protein.