Final answer:
The blue boxes refer to individual amino acids, and the red text indicates peptide bonds, forming a polypeptide. Peptide bonds form through condensation reactions between amino acids, resulting in the creation of polypeptides, which can eventually become proteins.
Step-by-step explanation:
The blue boxes in the given context surround individual amino acids. The red text shows the position of the peptide bonds or amide linkages joining the amino acids together, thus creating a polypeptide. Each amino acid contains an amine functional group (-NH₂), a carboxylic acid group (-COOH), and a distinct side chain, with 20 different amino acids commonly used to build proteins. When two amino acids join via a condensation reaction, a peptide bond is formed, and a molecule of water is released. This bond connects the carbonyl group of one amino acid with the amine group of another, allowing for the possibility of further peptide bonds with additional amino acids, leading to longer chains.
A dipeptide is formed when two amino acids are joined by a single peptide bond. As more amino acids are added, the chain becomes a polypeptide. When thousands of amino acids are joined in this way, they eventually form large proteins. The sequence and number of amino acids determine a protein's characteristics such as shape, size, and function.