Download Final Exam Questions - Structure and Function of Biomolecules | BIS 102 and more Exams Biology in PDF only on Docsity!
BIS 102 Name ___________________________________________________ Fall, 2008 Last First K. Hilt Final Exam Score (200): ___________
Equations: pH = pK (^) a + log {[b]/[a]} K (^) a = x 2 /(y-x) Kb = x 2 / (y-x) pH = (pKa 1 + pKa 2 )/2 (Ka)(K (^) b) = 1 x 10 - F = (q 1 q 2 ) / r^2 G = H - TS v (^) o = {V (^) max [S]}/ {K (^) m + [S]}
Amino acid pK (^) a ’s: -carboxyl group (2.1), -amino group (9.6) side chains: D (3.9) E (4.2) H (6.0) C (8.3) Y (10.1) K (10.5) R (12.5) Oligopeptide pK (^) a ’s: C-terminal carboxyl group (3.6), N-terminal amino group (7.4)
- An oligopeptide has the following structure:
( 5 pts.) a) What is the one-letter code (sequence) of this peptide? Put your answer on this line: _______________________________________________.
( 10 pts.) b) For the above oligopeptide to be drawn with those charges, the pH of the solution that it is in must be somewhere between what two pH’s? Answer: ______ < pH < ______.
( 5 pts.) c) Picking one of the peptide bonds in the above structure, carefully draw a rectangle around the atoms that form a plane around that peptide bond.
(10 pts.) d) Imagine that the intact oligopeptide was subjected to peptide sequencing using the Edman chemistry in the protein sequenator. The protein sequenator is run for one cycle. Using the axes drawn below, carefully draw in the expected result. Label your axes and your peak(s).
(10 pts.) e) What is the pI of the intact oligopeptide? Put your answer here: _________. To receive credit, you must show your work on the back of this or another page.
(10 pts.) f) At pH 6.3, would the above intact oligopeptide bind to CM-Sephadex or DEAE-Sephadex? Answer: ______________________. Show your calculations and thinking.
BIS 102 Name ___________________________________________
- (20 pts.) How many moles of H+^ do you need to add to change the pH of 500 ml of 0.100 M arginine solution, pH 12.7 to a final pH of 2.20? Put your answer here: _________ mol H+. To receive credit, you must show your work on the back of this or another page.
- Amino acid analysis of your pure protein Z was done. The results of this analysis are as follows:
Amino Acid Number of Residues in Enzyme Z
Amino Acid Number of Residues in Enzyme Z A 13 B 15 G 12 W 6 M 5 H 12 Z 24 C 4 K 8 V 24 R 12 S 12 L 23 T 14 Y 12 F 13 NH 4 +^10
Note: some NH 4 +^ ions were produced.
( 5 pts.) a) Where did the NH 4 +^ ions come from? Explain briefly.
( 20 pts.) b) What is the net charge, to the nearest 0.01, of your intact enzyme Z at pH 7.4? Put your answer on this line: _____________. To receive credit, show all calculations on the back of this or another page.
(10 pts.) c) Based on the data in the above table, which cutting tool ---CNBr, trypsin, or chymotrypsin, would be best to use, in order to make the best use of the protein sequenator? Explain.
- (10 pts.) Suggest an affinity column resin that you could use to purify hemoglobin from other proteins. What will your resin consist of? Why have you chosen those particular components?
BIS 102 Name ___________________________________________
- You are going to measure the enzyme activity of enzyme “T”. Enzyme “T” catalyzes the reaction: S P. Enzyme “T” has a K (^) m of 1.0 x 10 -6^ M for S. You mix the following solutions together: 2.60 ml 10 mM phosphate buffer, pH 7. 0.30 ml 30 mM S 0.10 ml enzyme “T”. The results of this enzyme assay are plotted below:
Time (seconds)
0 10 20 30 40 50
nmol P produced in assay 0
5
10
15
20
25
30
(5 pts.) a) How many I.U.’s of enzyme “T” were present in the above assay? Put your answer here: _____________________.
(10 pts.) b) What would the initial velocity be if the substrate concentration had initially been 1.5 x 10-6^ M? Show all calculations.
(10 pts.) c) Let’s assume that 1.0 x 10-13^ mol of enzyme “T” was present in both assaysi.e. in part “a” and in part “b”. Calculate the turnover number for enzyme “T”. Put your answer here: _____________. Show all calculations.
- (10 pts.) Imagine that you are purifying enzyme Z from a crude extract. How will you know when it is “pure”? Biochemists use two different criteria to determine if an enzyme is pure. What are those two criteria?
Criterion #1: ______________________________________________________________
Criterion #2: ______________________________________________________________
