SAS 12

• Amino Acid - A molecule containing both a carboxylic group and an amino group.
• R Group: The unique side chain attached to the alpha carbon in an amino acid.
• Alpha Amino Acid - A type of amino acid where the amino group is directly bonded to the alpha-carbon.
• Alpha Carbon: The carbon atom in an alpha amino acid bonded to the carboxylic acid, amino, hydrogen, and R group.
• Carboxylic Acid Group: The –COOH group present in every alpha amino acid.
• Amino Group: The –NH2 group present in every alpha amino acid.
• R = alkyl

  • Glycine
  • Alanine
  • Valine
  • Leucine
  • Isoleucine
  • Methionine
  • Proline
• R = aromatic group

  • Phenylalanine
  • Tryptophan
• Neutral

  • Tyrosine
  • Serine
  • Threonine
  • Cysteine
  • Glutamine
  • Asparagine
• Acidic

  • Glutamic acid
  • Aspartic acid
• Basic

  • Lysine
  • Histidine
  • Argenine
• Essential amino acids: Amino acids that must be obtained through the diet since the body cannot produce them.
• Non-essential amino acids: Amino acids that the body can synthesize on its own and are not required to be consumed through the diet.
• Essential:

  Histidine

  Isoleucine

  Leucine

  Methionine

  Phenyl alanine

  Threonine

  Tryptophan

  Valine
• Non essential:

  Alanine

  Arginine

  Aspargine Aspartate

  Cystine

  Glutamic acid

  Glycine

  Ornithine

  Proline

  Serine

  Tyrosine
• Peptide bonds: Formed by the reaction between the carboxyl group of one amino acid and the amino group of another during protein synthesis.
• Protein synthesis: During __________, the carboxyl group of amino acid at the end of the growing polypeptide chain reacts with the amino group of an incoming amino acid, releasing a molecule of water.
• water: During protein synthesis, the carboxyl group of amino acid at the end of the growing polypeptide chain reacts with the amino group of an incoming amino acid, releasing a molecule of ______.
• Proteins: Amino acids are the building blocks for ______ - nearly all proteins studied are made from the twenty standard amino acids.
• Zwitterion: At neutral pH (pH =7) both the acid and amine groups will be ionized to give the so-called ______ form.
• 20 Amino acids - nearly all proteins studied are made from the
• R groups: The protein amino acids are classified according to the chemical nature of their ______ as aliphatic, aromatic, heterocyclic, and sulphur-containing amino acids.
• Polarity: More meaningful classification of amino acids is based on the ______ of the R groups.
• Side Chains - are important in promoting hydrophobic interactions within protein structures.
• imino group of proline - is held in a rigid conformation and reduces the structural flexibility of the protein.
• Hydrophobic Aliphatic - includes glycine, alanine, valine, leucine. Isoleucine and proline.
• Hydrophobic Aromatic - includes phenylalanine, tyrosine and tryptophan.
• Stronger - because of stacking one another, aromatic is more ______ than aliphatic.
• polar and hydroxyl and nitrogen - Tyrosine and tryptophan are more ______ than phenylalanine due to the presence of ______ group in tyrosine and ______ in the indole ring of tryptophan
• ultraviolet light - absorption of at 280 nm by tyrosine, tryptophan and to a lesser extent by phenylalanine is responsible for the characteristic strong absorbance of light by proteins.
• Polar Uncharged - includes serine, threonine, cysteine, methionine, asparagine and glutamine.
• (Polar Uncharged) hydroxyl group - serine and threonine
• (Polar Uncharged) sulphur atom - cysteine and methionine
• (Polar Uncharged) amide group - asparagine and glutamine
• hydrophilic - Polar Unchared R groups are more ____ than the non-polar amino acids.
• (Polar Charged) Acidic: are aspartic and glutamic acids. These amino acids have a net negative charge at pH 7.0.
• (Polar Charged) Basic: This group includes lysine, arginine and histidine. The R groups have a net positive charge at pH 7.0
• amino acids are substances that are white crystaline
• amino acids Particularly those having several carbon atoms, have limited solubility in water but are readily soluble in polar organic solvent
• Amino acids have high melting points varying from 200-300 degree celsius or even more