About the genetic code@@ - (Feb/25/2008 )

My teacher gives me a RNA sequence

RNA: 5'GGC-AUG-GAC-CAU-AGA-GGA-CAG-UGA-CAAAAAA3'
Protein: ? M D H R G Q Stop


I would like to know why there is no amino acid in GGC ?? what does the purpose ?? THanks

Translation always starts with an ATG. Any upstream sequence is part of the 5' untranslated region, which is not translated into amino acids. Transcription of a gene begins before the ATG, so you will always have some sequence that is not translated. This is usually around 50-100 bases or so. Sometimes this sequence contains regulatory elements that aid in translation.