What provides the instructions for the order of amino acids in a specific protein?

What provides the instructions for the order of amino acids in a specific protein?

• A. the order of the DNA nucleotides
• B. the order of amino acids
• C. the order of sugars
• D. the order of lipids

Answer: (A)

DNA carries the genetic instructions for building proteins. The specific sequence of nucleotides in DNA is used to make messenger RNA, and the ribosome reads that mRNA in codons—three-nucleotide groups—each of which corresponds to one amino acid. So the order of amino acids in a protein is determined by the DNA sequence (via the mRNA), not by the order of sugars or lipids. The sugars are part of the nucleotide backbone, and lipids are a different class of biomolecules, so they don’t encode the amino acid sequence.

DNA carries the genetic instructions for building proteins. The specific sequence of nucleotides in DNA is used to make messenger RNA, and the ribosome reads that mRNA in codons—three-nucleotide groups—each of which corresponds to one amino acid. So the order of amino acids in a protein is determined by the DNA sequence (via the mRNA), not by the order of sugars or lipids. The sugars are part of the nucleotide backbone, and lipids are a different class of biomolecules, so they don’t encode the amino acid sequence.