Which of these is the smallest structure?
A. Dipeptide
B. Amino acid
C. Protein
D. Polypeptide
The smallest structure among the options provided is the amino acid. To understand why this is the case, let's break down each option and see how they relate to one another.
An amino acid is the basic building block of proteins. It consists of a central carbon atom (the alpha carbon) that is bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and an R-group (which varies among different amino acids). Amino acids can exist as individual molecules.
A dipeptide is formed when two amino acids join together through a peptide bond. A peptide bond is formed by a condensation reaction, where the carboxyl group of one amino acid reacts with the amino group of another amino acid, resulting in the release of a water molecule.
A polypeptide is a chain of amino acids linked together through peptide bonds. It can consist of many amino acids and can have a specific sequence determined by the genetic code.
A protein is a large, complex molecule composed of one or more polypeptides that have folded into a specific structure. Proteins are typically much larger than polypeptides and can have various functional roles in the body.
Now that we understand the relationship between these structures, we can determine that the amino acid is the smallest structure among the options provided.