What Is an Amino Acid?
An amino acid is an organic molecule that serves as the fundamental building block of proteins. Each amino acid contains a central carbon atom, known as the alpha-carbon, which is bonded to four different groups: an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (-H), and a variable side chain known as the R-group.
Section 2: The Core Structure
The structure of all amino acids is defined by the central alpha-carbon connected to the amino and carboxyl groups. The amino group is basic, while the carboxyl group is acidic. It is the R-group, or side chain, that varies among the different types of amino acids, giving each one its unique chemical properties, such as being acidic, basic, polar, or nonpolar.
Section 3: A Practical Example
A simple example of an amino acid is Glycine. In Glycine, its R-group is just a single hydrogen atom (-H). Another common example is Alanine, where the R-group is a methyl group (-CH3). These individual amino acids link together in long chains to form complex proteins like collagen or hemoglobin.
Section 4: Why Are Amino Acids Important?
Amino acids are crucial for life because they link together via peptide bonds to form polymers called proteins. Proteins perform a vast array of functions in the body, including acting as enzymes to catalyze reactions, providing structural support (like keratin in hair), transporting molecules (like hemoglobin), and signaling between cells.