Amino acids

Definition

Amino acids are organic compounds that serve as the building blocks of proteins, characterized by the presence of an amino group (-NH2), a carboxyl group (-COOH), and a unique side chain (R group) that determines the properties of each amino acid. They play crucial roles in various biochemical processes, including protein synthesis, metabolism, and signaling pathways, connecting fundamental principles of biochemistry to interorgan metabolism and adaptations during different physiological states.

5 Must Know Facts For Your Next Test

1. There are 20 standard amino acids that combine in various sequences to form proteins, each with unique properties based on their side chains.
2. Amino acids can be categorized into essential and non-essential types, with essential amino acids needing to be ingested through food because the body cannot produce them.
3. They not only contribute to protein structure but also play key roles in metabolic pathways, such as acting as precursors for neurotransmitters and hormones.
4. The metabolism of amino acids involves their deamination, where the amino group is removed, allowing the remaining carbon skeleton to enter various metabolic pathways.
5. In different physiological states, like fasting or exercise, the body prioritizes certain amino acids for energy production and protein synthesis, showcasing metabolic adaptations.

Review Questions

• How do amino acids contribute to the structure and function of proteins in living organisms?
  • Amino acids are fundamental to the structure of proteins as they are linked together by peptide bonds to form polypeptides. The sequence of amino acids in a protein determines its unique three-dimensional shape and function. This structure is critical for the protein's role in various biological processes, including catalysis by enzymes and structural support in cells.
• Discuss how the metabolism of amino acids varies between fed and fasting states in the body.
  • During fed states, excess dietary amino acids may be used for protein synthesis or converted into carbohydrates or fats for storage. In contrast, during fasting states, the body relies on amino acids for gluconeogenesis to maintain blood glucose levels. Additionally, certain amino acids can be catabolized for energy production when carbohydrate reserves are low, reflecting how the body's metabolic priorities shift based on nutritional status.
• Evaluate the impact of deficiencies in essential amino acids on metabolic adaptations during periods of physiological stress.
  • Deficiencies in essential amino acids can severely impair protein synthesis and overall metabolism during physiological stress. This deficiency can lead to muscle wasting, decreased immune function, and impaired recovery from illness or injury. Furthermore, during times of stress such as illness or intense physical activity, the body's need for certain amino acids increases, which can exacerbate these deficiencies and lead to further metabolic disruptions if not addressed through adequate dietary intake.

Related terms

Peptides: Short chains of amino acids linked by peptide bonds, which can function as hormones or neurotransmitters.

Enzymes: Proteins that act as biological catalysts to accelerate biochemical reactions, often requiring specific amino acids for their activity.

Essential Amino Acids: Amino acids that cannot be synthesized by the body and must be obtained from dietary sources.