Final answer:
Proteins consist of chains of amino acids, which are formed through the translation of messenger RNA (mRNA) based on the genetic code in DNA.
Step-by-step explanation:
Proteins consist of chains of amino acids, which are the building blocks that give proteins their structure and function. This process starts with the genetic code in DNA, which is transcribed to messenger RNA (mRNA), and then translated into a protein product through a sequence of amino acids. Each group of three nucleotides in the mRNA, known as a codon, specifies a single amino acid, thus a chain of multiple codons results in a polypeptide - the subunit of proteins. Proteins play crucial roles in the body, acting as enzymes, hormones, and structural components, and are essential for numerous biological processes.