Amino Acid

Definition

An amino acid is a simple organic compound that contains both an amino group (-NH2) and a carboxyl group (-COOH), along with a side chain unique to each amino acid. These building blocks of proteins play a crucial role in biological processes, serving as the foundation for protein structure and function, and influencing the properties of proteins through their side chains.

5 Must Know Facts For Your Next Test

1. There are 20 standard amino acids, each with distinct properties based on their side chains, which can be polar, nonpolar, acidic, or basic.
2. Amino acids can be classified into two groups: essential amino acids, which must be ingested through food, and non-essential amino acids, which the body can produce.
3. The sequence of amino acids in a protein determines its three-dimensional structure and, consequently, its function within the body.
4. Amino acids play key roles in metabolism beyond protein synthesis; they are involved in the synthesis of neurotransmitters and hormones.
5. Amino acids can exist in different forms (isomers) due to the chirality of the alpha carbon, with L-forms being the predominant type found in nature.

Review Questions

• How do the side chains of amino acids influence protein structure and function?
  • The side chains, or R groups, of amino acids play a crucial role in determining both the structure and function of proteins. Each side chain has specific chemical properties—such as being hydrophobic or hydrophilic—which influence how the amino acids interact with each other and with their environment. This interaction is essential for protein folding, stability, and ultimately how proteins perform their biological functions.
• Discuss the importance of essential amino acids in human nutrition and their role in protein synthesis.
  • Essential amino acids are vital because they cannot be synthesized by the body and must be obtained from dietary sources. They serve as the building blocks for proteins that are crucial for growth, repair, and maintenance of body tissues. Without adequate intake of essential amino acids, the body may struggle to produce necessary proteins, leading to various health issues such as muscle wasting and weakened immune response.
• Evaluate the relationship between amino acid sequences and protein function in living organisms.
  • The sequence of amino acids in a protein is critical to its function because it dictates how the protein will fold into its specific three-dimensional shape. This folding is influenced by interactions among side chains and between the backbone structure of the polypeptide chain. Even a single change in the sequence (mutation) can significantly alter a protein's structure and function, potentially leading to diseases or malfunctions in biological processes. Therefore, understanding this relationship is key in biochemistry and molecular biology.

Related terms

Peptide Bond: The covalent bond formed between two amino acids when the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water.

Side Chain (R Group): The variable group attached to the central carbon atom of an amino acid that determines its unique characteristics and properties.

Essential Amino Acids: Amino acids that cannot be synthesized by the body and must be obtained from the diet for proper protein synthesis and bodily function.