Chapter #10 Flashcards
(25 cards)
How are the fischer projections of amino acids drawn?
amino group on the left, all of them L amino acids (with S configurations other than cysteine which fucks it up).
what catalyzes the breaking of peptide bonds between amino acids?
strong acid or base
rotation is limited around a peptide bond because resonance gives the _____ bond partial double bond character
C-N
what are the starting reactants for strecker synthesis of amino acids?
aldehyde, ammonium chloride, potassium cyanide (water eventually used)
what is the final molecule at the end of step 1 of strecker synthesis?
aminonitrile
compare imine and nitrile
imine: double bond between C and N
nitrile: triple bond between C and N
what is the final molecule at the end of step 2 of strecker synthesis?
amino acid
what types of amino acids can strecker synthesis create?
L and D amino acids because it starts with a planar molecule
what types of amino acids can gabriel synthesis create?
L and D amino acids because it starts with a planar molecule
what are the types of reactions in strecker synthesis?
condensation reaction, nucleophilic addition, hydrolysis
what are the reactants in gabriel synthesis?
potassium phthalimide, diethly bromomalonate and alkyl halide (eventually water)
what are the types of reactions in gabriel synthesis?
2 x SN2, hydrolysis and decarboxylation
what is the role of phosphates in the backbone of DNA
connects sugars together
what is released when a nucleotide is added to a growing strand of DNA?
pyrophosphate (PPi)
what is another name for pyrophosphate?
PPi
what are the organic phosphates
ATP, GTP, etc.
phosphate group bonded to carbon containing material
what are the names of the forms of H3PO4?
H3PO4: phosphoric acid
H2PO4-: dihydrogen phosphate
HPO4-2: hydrogen phosphate
PO4-3: phosphate
at physiological pH, what form does phosphoric acid take?
H2PO4-: dihydrogen phosphate
HPO4-2: hydrogen phosphate
predominate in almost equal concentrations
why is phosphoric acid a good buffer?
has large variety of pKa values
the pKa values span pretty much the entire pH scale which allow it to pick up hydrogens at many different values.
why is the energy released by the cleavage of a phosphate so high?
adjacent phosphate groups experience a large amount of repulsion due to negative charges
resonance helps to stabilize this negative charge slightly.
inorganic phosphates
H2PO4-: dihydrogen phosphate
HPO4-2: hydrogen phosphate
all amino acids in eukaryotes are ___ amino acids
L
All amino acids in eukaryotes have ___ stereochemistry except ____
S
cysteine
in strecker synthesis, the carbonyl carbon ultimately becomes the ___ carbon
alpha
