23.2. Amino Acids and Proteins
By Abbie

Amino Acids - The Basics
  • Amino Acids are the basic building blocks of proteins.
  • By definition, Amino Acids are organic molecules that contain two functional groups: A basic NH2 amino group and an acidic (-COOH) carboxylic acid group.
The Structure of Amino Acids
There are 20 amino acids that all have the same basic structure.

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Amino Acid Reactions
Amino Acids react with each other.
Basic Amino Group (of one amino acid) + Acidic Carboxylic Acid Group (of another amino acid) ----> peptides + water
peptide bond - a bond formed as a result of the amino acid reaction
dipeptide - the product of the reaction because it is made up of two amino acid units.
polypeptides - longer chains
proteins - chains of 50 or more amino acids.
proteases - enzymes that break peptide bonds.

  • Amino Acids are extremely important to a protein chain because the difference of only one can cause a big change in a protein's activity in a cell.
  • Amino acid side chains also determine the shape and the structure of proteins.
  • A primary structure is the sequence of the amino acids in a polypeptide chain or protein.
  • A seconday structure describes how the chain is coiled or arranged.
  • Tertiary structures are the three-dimensional shapes of protein.
  • Quaternary structures are the four different polypeptides of hemoglobin.