BIOCHEM 384
BIOCHEM 384 EXAM 2 QUESTIONS AND
ANSWERS 2025
Which separation technique exploits the density differences of biomolecules and
organelles? - Centrifugation using centrifuge tubes in a rotor placed in a centrifuge.
What protein feature will cause the protein to bind to a metal in chelation affinity
chromatography—specifically, a resin with immobilized Ni2+? - Recombinant proteins
engineered to have six histidines at the N or C terminus of the protein.
Sodium dodecylsulfate (SDS) plays an important role in SDS PAGE. Select the correct
description of what SDS does in denatured electrophoresis. - SDS is an amphipathic
compound that binds to the hydrophobic portion of proteins and give a negative
charge derived from the polar head group such that proteins have a proportional charge to
mass ratio.
Which of the experimental steps
listed at the right is considered the most challenging in X-ray crystallography? -
Determining the phases of the diffracted X-rays.
Determine which major class of proteins best describes the specific representative
proteins listed.
a. Telomerase
b. Protein Kinase A
c. Actin polymer
d. Lactose permease
e. Hexokinase - a. Genomic caretaker
BIOCHEM 384
, BIOCHEM 384
b. Cell signaling
c. Structural protein
d. Transport protein
e. Metabolic enzyme
Which statement most accurately describes the structure and function of O2 transport
proteins. - Hemoglobin is a tetramer that can bind BPG and O2 whereas myoglobin binds
O2 but cannot bind BPG.
Assume that in the graph at the right, the curve represented by Y is
normal adult hemoglobin at pH 7.4 with normal levels of 2,3-BPG. Which of the
statements below is the most correct regarding curves X and Z? - Z represents O2 binding
in cells with elevated 2,3-BPG, whereas X represents O2 binding in cells with
decreased 2,3-BPG.
In one type of hemoglobin mutant the amino acid change generates a strong ionic
interaction
stabilizing the T state conformation but only under conditions of lower pH, e.g., at pH 7.2
compared to pH
7.6. What effect would this mutation have on the amount of O2 delivered to the tissue
and why? - More O2 delivered to the tissue because the R-T equilibrium would be shifted
to the T state in tissues.
What is the energy requirement to
transport 3 moles of Na+ from the inside to outside? - +41.2 kJ
What is the energy requirement to
transport 2 moles of K+ from the outside to inside? - +3.7 kJ
BIOCHEM 384
BIOCHEM 384 EXAM 2 QUESTIONS AND
ANSWERS 2025
Which separation technique exploits the density differences of biomolecules and
organelles? - Centrifugation using centrifuge tubes in a rotor placed in a centrifuge.
What protein feature will cause the protein to bind to a metal in chelation affinity
chromatography—specifically, a resin with immobilized Ni2+? - Recombinant proteins
engineered to have six histidines at the N or C terminus of the protein.
Sodium dodecylsulfate (SDS) plays an important role in SDS PAGE. Select the correct
description of what SDS does in denatured electrophoresis. - SDS is an amphipathic
compound that binds to the hydrophobic portion of proteins and give a negative
charge derived from the polar head group such that proteins have a proportional charge to
mass ratio.
Which of the experimental steps
listed at the right is considered the most challenging in X-ray crystallography? -
Determining the phases of the diffracted X-rays.
Determine which major class of proteins best describes the specific representative
proteins listed.
a. Telomerase
b. Protein Kinase A
c. Actin polymer
d. Lactose permease
e. Hexokinase - a. Genomic caretaker
BIOCHEM 384
, BIOCHEM 384
b. Cell signaling
c. Structural protein
d. Transport protein
e. Metabolic enzyme
Which statement most accurately describes the structure and function of O2 transport
proteins. - Hemoglobin is a tetramer that can bind BPG and O2 whereas myoglobin binds
O2 but cannot bind BPG.
Assume that in the graph at the right, the curve represented by Y is
normal adult hemoglobin at pH 7.4 with normal levels of 2,3-BPG. Which of the
statements below is the most correct regarding curves X and Z? - Z represents O2 binding
in cells with elevated 2,3-BPG, whereas X represents O2 binding in cells with
decreased 2,3-BPG.
In one type of hemoglobin mutant the amino acid change generates a strong ionic
interaction
stabilizing the T state conformation but only under conditions of lower pH, e.g., at pH 7.2
compared to pH
7.6. What effect would this mutation have on the amount of O2 delivered to the tissue
and why? - More O2 delivered to the tissue because the R-T equilibrium would be shifted
to the T state in tissues.
What is the energy requirement to
transport 3 moles of Na+ from the inside to outside? - +41.2 kJ
What is the energy requirement to
transport 2 moles of K+ from the outside to inside? - +3.7 kJ
BIOCHEM 384
