Amino acids are made up of a central carbon bonded to an amino group (–NH 2), a carboxyl group (–COOH), and a hydrogen atom. The R group is the only difference in structure between the 20 amino acids otherwise, the amino acids are identical. Every amino acid also has another variable atom or group of atoms bonded to the central carbon atom known as the R group. Each amino acid has the same fundamental structure, which consists of a central carbon atom bonded to an amino group (–NH 2), a carboxyl group (–COOH), and a hydrogen atom. All proteins are made up of different arrangements of the same 20 kinds of amino acids.Īmino acids are the monomers that make up proteins. Changes in temperature, pH, and exposure to chemicals may lead to permanent changes in the shape of the protein, leading to a loss of function or denaturation (to be discussed in more detail later). Protein shape is critical to its function. For example, hemoglobin is a globular protein, but collagen, found in our skin, is a fibrous protein. Proteins have different shapes and molecular weights some proteins are globular in shape whereas others are fibrous in nature.

They are all, however, polymers of amino acids, arranged in a linear sequence. Their structures, like their functions, vary greatly. Each cell in a living system may contain thousands of different proteins, each with a unique function. Proteins may be structural, regulatory, contractile, or protective they may serve in transport, storage, or membranes or they may be toxins or enzymes. Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules.

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