Midterm 1

components of cells

euglena experiment

mg+2 deficient causes the cell to look multilobed

amino acids

• inside is nonpolar/hydrophobic

• outside is polar/hydrophillic

  • bc outside environment is aq soln

amino acids (cont)

• L-amino acid (means on left)

  • all aa except glycine bc it doesn’t have a chiral center(R group is an H)

• L and D aa CANNOT bond together

pKa vs pH

• pkA is derived from Ka(acid dissociation constant) of an acid

  • determines how much the acid is dissociated in soln

  • the LOWER the pKa, the STRONGER the acid

• when pH=acid’s pKa, the acid is 50% deprot and conc of the acid=conj base

• pH expresses conc of H+ ions in a soln

• pKa is special pH for that molecule

  • below that pH, molecule will be bonded to an H+ ion

  • above that pH, it won’t

  • at the pH, it’ll be 50/50

ALL THE AMINO ACIDS

ionizable(can accept/donate a H+)

• acidic aa (-vely charged, ionizable)

  • aspartic acid(D), glutamic acid(E)

• basic aa(+vely charged)

  • lysine(K), arginine(R), histidine(H)

• tyrosine(Y), cysteine(C)

  • -vely charged

hydrophobic

• leucine(L), isoleucine(I), valine(V), alanine(A), methionine(M), proline(P), phenylalanine(F), tryptophan(W)

polar side chains

• serine(S), threonine(T), cysteine(C), asparagine(N), glutamine(Q), tyrosine(Y)

nonpolar, nonpolar side chains

• glycine(G), alanine(A), valine