Answer:
A protein-coding gene has an open reading frame (ORF) that make easier its identification
Step-by-step explanation:
During translation, the messenger RNA (mRNA) is read by the ribosomes as triplets of nucleotides called codons in the open reading frame (ORF). An ORF can be defined as a gene fragment composed of codons which are translated into amino acids in a polypeptide chain. According to the genetic code, the information encoded by these codons will specify the sequence of amino acids in the protein, as well as the start codon and stop codons of the protein-coding genes. A start codon (AUG) is a site at which translation into protein begins, while stop codons (UAA, UAG, and UGA) mark the site at which translation ends. Moreover, non-coding RNAs (ncRNAs) don't have ORFs because they do not encode for proteins, and therefore their identification is more difficult.