What determines the sequence of amino acids in a protein?

The sequence of amino acids in a protein is determined by the arrangement of nucleotides in DNA. This connection is central to the process of gene expression, which can be broken down into transcription and translation.

During transcription, a specific segment of DNA is transcribed into messenger RNA (mRNA), and this mRNA serves as a template for protein synthesis during translation. Each group of three nucleotides in the mRNA, known as a codon, corresponds to a specific amino acid or a stop signal during the protein synthesis process. Thus, the specific sequence of nucleotides in the DNA ultimately dictates the order of amino acids in the resulting polypeptide chain.

The other options address components involved in protein synthesis but do not directly determine the amino acid sequence. For instance, while mRNA is crucial for displaying the sequence of codons that inform amino acid order, it is originally derived directly from the nucleotide sequence of the DNA. Ribosomes facilitate the translation process but do not dictate the sequence; they read the mRNA and help assemble the amino acids. Enzymes are important in various metabolic reactions and processes but again do not decide how amino acids are sequenced in proteins.