Proteins

• Proteins are important for structure, function, and regulation of tissues and organs
• Catalysts are chemical agents that selectively speed up chemical reactions without being consumed
• • Amino acids are the monomers, or building blocks of proteins
  • They contain carbon, hydrogen, oxygen, and nitrogen atoms
  • There are 20 types of amino acids
• A protein is a biologically functional molecule made up of one or more polypeptides
• A polypeptide is a polymer of amino acids
• Amino acids are organic molecules with an amino group (NH2) and a carboxyl group (COOH)
• Proteins have four important parts around a central carbon (alpha carbon)

  • An amino group (NH2)
  • A Carboxyl group (COOH)
  • A hydrogen
  • An R-group(side chain)
• Amino acids differ only in the R-group

  • The side chain (R-group) polarity affects whether an amino acid is more hydrophobic or more hydrophilic
  • The physical and chemical properties of the side chain determine the unique characteristics of a particular amino acid, thus affecting its functional role in a polypeptide
• • One group of amino acids have hydrophobic R groups
  • Another group of amino acids have hydrophilic R groups
  • A third group of amino acids includes those with functional groups that are charged (ionized) at cellular pH
• Amino acids are joined together when a dehydration reaction removes a Hydroxyl group (OH) from the carboxyl (COOH) end of one amino acid, and a hydrogen from the amino group (NH2) of another amino acid
• Amino acids are inked by peptide bonds
• Peptide Bond: The covalent bond between the carboxyl group (COOH)on one amino acid and the amino group (NH2) on another, formed by a dehydration reaction
• A functional protein consists of one or more polypeptides twisted, folded, and coiled into a unique shape