Amino Acids Study Notes

1. structure of amino acids central carbon, amino group, carboxyl group, R group 2. formation of polypeptides -when carboxyl group of one amino acid reacts with the amino group of another amino acid -condensation reaction- H2O produced -bond=rigid and planar -made from 100 amino acids 3. what does direc- protein has two ends that are chemically distinct from tionality mean? eachother 4. amphoteric prop- have acidic(COO-) and basic(NH3+) groups erties of amino acids 5. melting point of amino acids 200+ 6. amino acids sol- -soluble in water and polar solvents ubility -insoluble in no-polar solvents(benzene) 7. functions of pro- -catalysts(enzymes) teins -transport and store other molecules(oxygen) -tissue structure(collagen) -immune protection(antibodies) -movement generation(myosin) -transmit nerve impulses(ion channels) -gene regulation(transcription factor) 8. proteins as enzymes -act as catalysts for reaction to be quick and efficient 9. as hormones 1/5 released by endocrine glands, transported to target organ -growth hormone-promotes growth -insulin and glucagon-regulates blood glucose -thyroxine-regulates metabolic rate -antidiuretic hormone-regulation of fluid and electrolyte balance 10. transport proteins -transport sodium picks sodium from inside the cell -protein changes shape and releases sodium outside the cell -protein picks up potassium from outside the cell, changes shape and releases potassium in cell 11. proteins in immu- antibodies are giant proteins that bind to specific invaders nity such as viruses antigens cause body to produce antobodies 12. primary structure of protein: -sequence of amino acids in a polypeptide chain -sequence of protein is determined by DNA that encodes for that specific protein -change in DNA sequence, even one amino acid can change the proteins overall structure and function 13. change in DNA -one of the polypeptides chains that make haemoglobin sequence-sickle has slight change cell anaemia -glutamic acid on one of the chains replaced with valine-single amino acid sub -protein changes shape, exposing hydrophobic patch, reduces elasticity=anaemia 14. secondary struc- -general 3D formation of local segment proteins ture of protein: -alpha helix-rode like structure with peptide bonds tightly packed together -b pleated sheet-two or more polypeptide chains line up next to each other forming sheet 15. tertiary structure -overall 3D structure- interaction of R groups of protein of protein: -hydrophobic interactions: hydrophobic r groups inside of protein and hydrophilic amino acid on the outside to interact with protein 2/5 -disulphide bonds- covalent linkages between sulfur chains of cysteine -hydrogen bonds -ionic bonds 16. quaternary struc- multiple polypeptide chains(subunits) come together ture of protein held together by disulphide bonds, ionic bonds, hydrogen bonds, and van der waals forces 17. fibrous proteins -stronger and more flexible -hydrophobic in water-contain hydrophobic amino acid residues -keratin and collagen 18. globular proteins -polypeptide chains folded in spherical or globular shape -enzymes, transport proteins, haemoglobin, -water soluble 19. protein denatura- disruption of weak types of interaction(van der waals, tion H-bonds) leads to loss in proteins biological activity -extreme temperature and pH -high salt concentration -organic solvents- alcohol 20. zwitterions molecules with both a positive and negative charge that cancel each other out 21. why are amino acids zwitterions? carboxyl group has -ve charge amino group has +ve charge overall charge is neutral 22. what happens to carboxyl group accepts proton and becomes uncharged amino acids at overall charge= +ve low pH? 23. 3/5 what happens to amino group loses its proton amino acids at overall charge= -ve high pH? 24. non-essential amino acids amino acids made within the body -glycine -alanine -serine -tyrosine -asparagine -aspartic -glutamic acid -glutamine -proline 25. essential amino acids must be obtained from food -valine -leucine -isoleucine -threonine -methionine -arginine -lysine -histidine -phenylalanine -tryptophan 26. phenylalanine -essential amino acid -involved in production of neurotransmitters norepinepherine and dopamine -production of melanin, meat and eggs 27. neutral non polar glycine, alanine, valine, cysteine, proline, leucine, amino acids isoleucine, methionine, tryptophan, phenylalanine 4/5 28. neutral polar amino acids serine, threonine, tyrosine, asparagine, glutamine 29. basic(+ve charge) amino acids lysine, arginine and histidine 30. acid (-ve charge) aspartic acid and glutamic acid amino acids 31. why does glycine simplest and amino acid not have a chiral R group is a hydrogen- not bonded to 4 different carbon? groups-not chiral 5/5