• joined by polypeptide bonds
• always occure by formation of a covalent bond between an amino group and carboxyl group through dehydration
• building blocks of proteins
• 20 naturally occuring amino acids
• their R groups is what makes them all different

hydrogen bond between every 4 peptide bonds

chain must fold to bring chain close enough to form h bonds

• When a protein loses its native shape because of a change in PH, salt concentration, temperature ect.
• protein becomes biologically inactive
• often occures when it goes from an aqueous environment to an organic solvent
• agents that distrub hydrogen or ionic bonds or disulfide bridges that maintain a proteins shape
• may occure in excessive heat

• covalent bonds that form where two cysteine monomers, amino acids with sulfhydryl groups on their side chains are brought close together by the folding of the protein
• the sulfur of one cyteine bonds to the sulfur of the second, and the disulfide bridge rivets parts of the protein together.

• sequence of amino acids in chain
• chain goes from amino end to carboxyl end

• not all proteins require this
• polypeptides wrap around together
• 3-chains called collagen
  • ex: hemaglobin

• repeated interactions between peptide bonds that are hydrogen bonds
  • alpha helix
  • b pleated sheet

• hereditary disorder caused by the substitution of one amino acid (valine) for a normal one (glutamic acid) at a particular position in the promary structure of hemoglobin, the protein that carries oxygen in red blood cells
• cells crystalize deforming into a sickle shape

• results from irregular interactions between R groups
  • h-bonds between polar r groups
  • ionic bonds between charged r groups
  • disulfide bridges
  • hydrophobic interactions