UTR stands for

• A. Untranslated Region
• B. Upstream Transcribed Region
• C. Universal Translation Region
• D. Unique Transcript Region

Answer: (A)

UTR refers to the Untranslated Region—the parts of an mRNA that are transcribed from DNA but not translated into protein. These regions flank the coding sequence: the 5' untranslated region lies before the start codon, and the 3' untranslated region lies after the stop codon. They don’t code for amino acids, yet they orchestrate important regulatory roles, such as controlling translation efficiency, mRNA stability, and localization through sequences and structures that interact with ribosomes and various RNA-binding proteins or microRNAs.

The other terms don’t match the established meaning. Upstream Transcribed Region isn’t a standard term for this concept, and Universal Translation Region or Unique Transcript Region aren’t recognized descriptors in molecular biology.