BCH 403 Final Exam UPDATED ACTUAL Questions and CORRECT Answers
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Course
BCH 403
Institution
BCH 403
BCH 403 Final Exam UPDATED ACTUAL
Questions and CORRECT Answers
T or F: A biochemical reaction, without a catalyst or thermodynamic coupling, takes 50 years
to reach a state of equilibrium. W/o more information, we cannot make a determination on
either the value of the Keq constant or the po...
BCH 403 Final Exam UPDATED ACTUAL
Questions and CORRECT Answers
T or F: A biochemical reaction, without a catalyst or thermodynamic coupling, takes 50 years
to reach a state of equilibrium. W/o more information, we cannot make a determination on
either the value of the Keq constant or the positive or negative value of the DeltaG of the
reaction - CORRECT ANSWER✔✔- False
T or F: Due to its small size, the amino acid glycine can be found in tight turns in a protein
structure - CORRECT ANSWER✔✔- True
T or F: The Delta G of a reaction is defined as the energy required to bring the concentration
of reactants and products to equal concentration - CORRECT ANSWER✔✔- False
T or F: One strength of NMR is that it can detect multiple conformations of proteins and one
of its limitations is that proteins must contain certain isotopes - CORRECT ANSWER✔✔-
True
T or F: A single residue mutation to an enzyme decreases its rate constant by one half. This
means the reaction now occurs more slowly. - CORRECT ANSWER✔✔- True
T or F: The hydrophobic packing of non-polar residues is thermodynamically favorable b/c of
both the hydrophobic effect and a larger number of weak van der waals - CORRECT
ANSWER✔✔- True
T or F: The classic experiment in which the protein ribonuclease A is first denatured and
reduced, then refolded, was used to demonstrate the role of aromatic residues in stabilizing
covalent disulfide bonds - CORRECT ANSWER✔✔- False
T or F: One reason that we require myoglobin and hemoglobin to store and transport oxygen
is b/c oxygen itself has very poor solubility in water - CORRECT ANSWER✔✔- True
T or F: A mutation in myoglobin that changes the distal histidine into alanine will result in a
lower P50 - CORRECT ANSWER✔✔- False
,The stability of an alpha helix is partly due to hydrogen bonding that occurs between
carbonyl oxygen of one helix and the amino hydrogen of a neighboring alpha helix -
CORRECT ANSWER✔✔- False
Which of the following statements if true regarding the hydrophobic effect - CORRECT
ANSWER✔✔- Non-polar molecules are driven together in order to maximize the entropy of
water
The peptide in question 17 is dissolved into a soln that has a pH of 6.5. Under these
conditions, the net charge of the peptide is - CORRECT ANSWER✔✔- +1
A glycine residue is disruptive to the stability of an alpha helix or a beta strand because -
CORRECT ANSWER✔✔- It's R group is too small to participate in stabilizing interactions
with neighboring R groups
With a pKA of 6.37, the carbonic acid/bicarbonate system serves to buffer changes to the pH
of blood. The acid dissociates as follows
H2CO3 + H20 ----> (DOUBLEARROW) HCO3- + H3O+
If a solution of .5 M carbonic acid is adjusted to a pH of 2.5, the primary form of the buffer
will be: - CORRECT ANSWER✔✔- H2CO3
Most non-polar residues are located on the interior of a protein fold, but are occasionally
found on surfaces where they can mediate protein interactions. The molecular basis of a
hypothetical infectious disease is that a bacterial protein interacts with a human protein by
sharing a non-polar surface. Your goal as a researcher is to find a way to disrupt this
interaction. Which of the following surface mutations are most likely to disrupt the protein
interaction? - CORRECT ANSWER✔✔- leucine-->glutamine
You've discovered a new species of rodent living at a very high altitude, where the partial
pressure of oxygen is low. What would you predict regarding the oxygen-binding capacity of
this new species? - CORRECT ANSWER✔✔- It's hemoglobin will have a very low P50
value AND The primary amino acid sequence of its hemoglobin will not be identical to that
of a species living in an oxygen-rich atmosphere
, The following peptide is composed of which amino acid sequence - CORRECT
ANSWER✔✔- LKQIFKDIWTIGW
The following sequence of 16 residues represents an alpha helical stretch in an enzyme from
the bacterium that causes tuberculosis. Which of the following is NOT TURE regarding the
structure of this alpha helix
QFLRDTANSLLDNLIT - CORRECT ANSWER✔✔- Mutation of they phenylalanine
residue to a proline will prevent the rest of the sequence from forming an alpha helix
The residue sequence of a fibrous protein is show below. Which protein does it most likely
correspond to?
Which of the following is true regarding oxygen binding to one molecule of myoglobin -
CORRECT ANSWER✔✔- A histidine is required to hydrogen-bond with the bound oxygen,
thus stabilizing it AND the iron atom is located outside the plane of the heme when oxygen is
not bound
A chromatography column was used to try to purify a protein that is 10 kDa in size. Some of
the elution fractions were run on SDS-PAGE and are shown blow ,with lower numbered
fractions eluting first. Based on this information, what kind of chromatographic column was
used and was this attempt successful? The charges on the gel are shown on the left -
CORRECT ANSWER✔✔- Gel filtration, and it did work
Your goal is to separate a mixture of the two polypeptides shown below, and obtain a purified
peptide 1 for further study as a neurotransmitter. Which purification technique would be most
effective and why?
Peptide 1: MHTRRAPLQAWKKPRADHVL
Peptide 2:
MHTDEAPLQAWKDPEADHVLW - CORRECT ANSWER✔✔- Cation exchange, since
peptide 1 is more positively charged and will "stick" to that resin best
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