How To Draw Molecule At Ph 10
i. (xx points) Write accurate structures for the following, including clear stereochemistry:
a) ArgAsn at pH 7
b) an H-bonded A - T base pair (just the bases)
c) isopentenyl pyrophosphate ( at pH 7)
d) BOC-protected ProPhe (at pH 7)
2. (fifteen points) The pKa values for glutamic acid are 2.ii, 4.three, and ix.7.
Write the expected major structures at
pH 1 
pH 3 
pH 7 
pH ten 
Explain why the two carboxy groups have different pKa values - including an explanation for why one is a stronger acid than the other.
The alpha carboxy ionizes when there is a NH3+ substituent nearby - this is an electron-withdrawing group that strengthens the acid - more so the alpha carboxy than the more remote gamma carboxy.
3a. (10 points) Cardiolipin is common in heart muscle. The structure of a typical cardiolipin is shown below. Evidence the expected products from complete hydrolysis, including the number of moles of each production expected from i mole of cardiolipin.
One equivalent of each of the iv fat acids:
R1COOH, R2COOH, R3COOH, and R4COOH
3 equivalents of glycerol:
HOCHiiCHOHCH2OH
Two equivalents of phosphate:
PO4 -3
3b. (ten points) Lithocholic acrid is a representative bile acrid, used to solubilize fats. Place all of the substituents (x of them) onto the chair diagram.
iv. (10 points) Flexibilene, found in a marine coral, has an unusual 15-membered ring construction.
Circumvolve each of the isoprene units in flexibilene.
Predict which bail is the last ane fabricated, creating the ring from an acyclic precursor.
(identify a clear arrow pointing to the bail)
The acyclic forerunner is a diterpene diphosphate. Predict its structure.
5. (twenty points) The conversion of nucleic acids bases from their carbonyl to enol forms can be catalyzed by either acid or base of operations. First with cytosine (which has only one carbonyl) and evidence mechanisms for converting it to its enol grade, using acid or base. Show all resonance forms for the intermediate in each case.
cytosine (carbonyl grade) <======= (acid, H+ ) =======> cytosine (enol form)
cytosine (carbonyl grade) <======= (base, OH- ) =======> cytosine (enol form)
6. (15 points) Identify the unknown heptapeptide based on the following data.
Complete hydrolysis gives 1 equivalent each of Arg, Asp, Gly, Pro, Ser, Tyr, Val
Edman deposition releases Asp
Carboxypeptidase releases Pro, then Gly
Chymotrypsin cleavage gives a tetrapeptide A and tripeptide B
Trypsin cleavage gives a tetrapeptide C and a tripeptide D
A and D take Asp at their Northward-termini
B has Val at its N-terminus and C has Tyr at its N-terminusAsp-Ser-Arg-Tyr-Val-Gly-Pro
Using merely the amino acids found in the heptapeptide above, give examples of side concatenation interactions that illustrate
a) charged group attractions
b) H-bonding attractions
plus other possibilities
Source: http://web.pdx.edu/~wamserc/C336S07/E3ans.htm
Posted by: riversmally1961.blogspot.com
0 Response to "How To Draw Molecule At Ph 10"
Post a Comment