Download Review Problems week 11 plus any problems left over from last week

Review Problems week 11 plus any problems left over from last week
1) Threonine is derived from what non-proteinacious amino acid? Which common amino acid is
the ultimate source of this molecule?
2) The methyl group of methionine is derived from what common amino acid? What is the
byproduct of this one carbon transfer? What cofactor catalyzes this carbon cleavage? What is
the acceptor of this carbon? The actual agent that ultimately transfers the carbon is which
cofactor?
3) Methionine may be synthesized from two complementary sets of amino acids. What are these
two sets?
4) Alpha-ketoglutarate provides the carbon skeleton for which amino acids?
5) Two different amidation methods are used to install side chain amides in amino acids.
Describe these two methods and match them to the relevant amino acid.
6) Which amino acids derive their carbon skeletons completely from oxaloacetate?
7) Which amino acid is derived from oxaloacetate and pyruvate? What carbon piece is lost in
this process? What cofactor plays a role in this process? Draw a general mechanism for this
reaction. What molecule plays a role as a protecting group in this pathway?
8) Serine is derived from which glucogenic precursor?
9) Inhibition of a key enzyme activity by the end product of a biosynthetic pathway is known as
what?
10) Why is it useful to have multiple isozymes of enzymes that comprise common pathways to
multiple amino acids?
11) Partial inhibition of a key enzyme activity by multiple compounds derived from an end
product is known as what? Why is this kind of function useful?
12) Describe how enzyme levels within a cell may be modified.
13) What are the two general pathways by which nucleotides are obtained?
14) What three molecules donate the heavy atoms for biosynthesis of the pyrimidine ring?
15) What carbon fragment is lost in the conversion of orotidylate to uridylate? What is
remarkable about this reaction?
16) CTP is formed from which precursor? What is the nitrogen donor? What is the energy
requirement for this reaction? Why is this necessary?
17) Describe how one can derive the contribution of binding energy of a fragment of the
substrate toward catalysis. (Use the experiment relative to orotidylate decarboxylase)