BCH 403 Final Exam question and correct answer latest 2025 100% complete

BCH 403 Final Exam question and correct
answer latest 2025 100% complete

QUESTION 1

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

False



QUESTION 2

T or F: Due to its small size, the amino acid glycine can be found in tight turns in a protein structure

True



QUESTION 3

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

False



QUESTION 4

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

True



QUESTION 5

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.

,True



QUESTION 6

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

True



QUESTION 7

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

False



QUESTION 8

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

True



QUESTION 9

T or F: A mutation in myoglobin that changes the distal histidine into alanine will result in a lower P50

False



QUESTION 10

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

False



QUESTION 11

Which of the following statements if true regarding the hydrophobic effect

Non-polar molecules are driven together in order to maximize the entropy of water

, QUESTION 12

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

+1



QUESTION 13

A glycine residue is disruptive to the stability of an alpha helix or a beta strand because

It's R group is too small to participate in stabilizing interactions with neighboring R groups



QUESTION 14

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:

H2CO3



QUESTION 15

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?

leucine-->glutamine



QUESTION 16

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?

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



QUESTION 17