BIOC 384 Exam 2 , ( UPDATED ACTUAL Exam Questions
and CORRECT Answers ) , 100% Verified, A+ Graded [
2025 Edition] , Success Guaranteed!
Although most protein sequencing is now done by mass spectrometry (MS), Edman degradation
(ED) is useful if large amounts of a protein can be obtained even if from an uncharacterized
species. Answer the True/False questions regarding methods used to sequence a polypeptide
fragment: - ANSWER False - The N-terminal residue removed by acid treatment in ED is always a
methionine.
False - Trypsin and chymotrypsin treatment often provides identical peptide fragments for ED
True - Genomic sequences are needed to predict protein sequences by the MS method.
True - Trypsin treatment provides useful sequence information when analyzing data from MS.
False - Protein sequencing by ED does not require purified protein but sequencing by MS does
X-ray crystallography (XRC) and nuclear magnetic resonance (NMR) spectroscopy provide three
dimensional structural information about the position of atoms in a purified protein. Name one
advantage
(adv) and one disadvantage (dvg) of each technique with regard to high resolution protein
structures. - ANSWER XRC/adv; large proteins, XRC/dvg; requires crystals, NMR/adv; soluble
protein, NMR/dvg; small proteins
Protein-specific antibodies are useful experimental tools in biochemistry. Choose the one
statement below that most correctly describes these biochemical reagents. - ANSWER
Polyclonal antibodies are a heterogeneous mixture of antibodies that recognize epitopes on an
antigen.
,Match each representative protein with the most correct specific major protein functional class.
Record your answer in the order of a, b, c, d, and e, by choosing the numbers 1, 2, 3, 4, and 5. -
ANSWER Cell signaling: G Protein-coupled receptor
Metabolic Enzyme: Malate dehydrogenase
Genomic Caretaker: RNA polymerase
Structural Protein: Tubulin
Transport Protein: Na+/K+ ATPase
Which statement most accurately describes the structure and function of O2 transport proteins.
- ANSWER Hemoglobin is a tetramer that can bind BPG and O2 whereas myoglobin binds O2 but
cannot bind BPG.
Answer the following questions about the graph shown at the right.
1. The protein with the lowest dissociation constant (Kd) is protein (A or B)?
2. The protein with the highest affinity for oxygen is protein (A or B)?
3. The protein most likely to bind oxygen cooperatively is protein (A or B)?
4. The protein most likely to be an oxygen storage protein is protein (A or B)?
5. The protein most likely to be hemoglobin is protein (A or B)?
6. The protein most likely to be myoglobin is protein (A or B)? - ANSWER (1) protein A (2)
protein A (3) protein B (4) protein A (5) protein B (6) protein A
*Refer to image
, In one type of hemoglobin mutant the amino acid change eliminates a hydrogen bond that
normally stabilizes the R state. Would you expect this mutant hemoglobin to have a higher or
lower O2 affinity compared to the normal protein and why? - ANSWER Lower O2 affinity
because the R-T equilibrium would be mostly shifted to the T state.
What is the effect of pH on O2 binding in the lungs compared to the tissues and why? - ANSWER
The correct answer is not given.
A transporter protein transports Ca2+ ions across a membrane at 37 °C in a cell in which the
membrane potential is 100 mV (inside of the cell is negative relative to the outside) and the
Ca2+ ion concentrations are 150 mM inside and 15 mM outside.
What is the DG when transporting 2 Ca2+
from the inside to the outside of the cell? - ANSWER +26.2 kJ/mol
A transporter protein transports Ca2+ ions across a membrane at 37 °C in a cell in which the
membrane potential is 100 mV (inside of the cell is negative relative to the outside) and the
Ca2+ ion concentrations are 150 mM inside and 15 mM outside.
What is the DG when transporting 2 Ca2+
from the outside of the cell to the inside of the cell? - ANSWER -26.2 kJ/mol
The solute concentration and the membrane potential each contribute to the total energy
requirement for transport. Based on your DG calculations above, which direction of transport
would be more energetically favorable (-DG) under the same conditions of solute concentration
and membrane potential if 2 glucose molecules were transported across the membrane rather
than 2 Ca2+ ions and why? - ANSWER Inside to Outside is more favorable because solute
concentration flows down the gradient.
and CORRECT Answers ) , 100% Verified, A+ Graded [
2025 Edition] , Success Guaranteed!
Although most protein sequencing is now done by mass spectrometry (MS), Edman degradation
(ED) is useful if large amounts of a protein can be obtained even if from an uncharacterized
species. Answer the True/False questions regarding methods used to sequence a polypeptide
fragment: - ANSWER False - The N-terminal residue removed by acid treatment in ED is always a
methionine.
False - Trypsin and chymotrypsin treatment often provides identical peptide fragments for ED
True - Genomic sequences are needed to predict protein sequences by the MS method.
True - Trypsin treatment provides useful sequence information when analyzing data from MS.
False - Protein sequencing by ED does not require purified protein but sequencing by MS does
X-ray crystallography (XRC) and nuclear magnetic resonance (NMR) spectroscopy provide three
dimensional structural information about the position of atoms in a purified protein. Name one
advantage
(adv) and one disadvantage (dvg) of each technique with regard to high resolution protein
structures. - ANSWER XRC/adv; large proteins, XRC/dvg; requires crystals, NMR/adv; soluble
protein, NMR/dvg; small proteins
Protein-specific antibodies are useful experimental tools in biochemistry. Choose the one
statement below that most correctly describes these biochemical reagents. - ANSWER
Polyclonal antibodies are a heterogeneous mixture of antibodies that recognize epitopes on an
antigen.
,Match each representative protein with the most correct specific major protein functional class.
Record your answer in the order of a, b, c, d, and e, by choosing the numbers 1, 2, 3, 4, and 5. -
ANSWER Cell signaling: G Protein-coupled receptor
Metabolic Enzyme: Malate dehydrogenase
Genomic Caretaker: RNA polymerase
Structural Protein: Tubulin
Transport Protein: Na+/K+ ATPase
Which statement most accurately describes the structure and function of O2 transport proteins.
- ANSWER Hemoglobin is a tetramer that can bind BPG and O2 whereas myoglobin binds O2 but
cannot bind BPG.
Answer the following questions about the graph shown at the right.
1. The protein with the lowest dissociation constant (Kd) is protein (A or B)?
2. The protein with the highest affinity for oxygen is protein (A or B)?
3. The protein most likely to bind oxygen cooperatively is protein (A or B)?
4. The protein most likely to be an oxygen storage protein is protein (A or B)?
5. The protein most likely to be hemoglobin is protein (A or B)?
6. The protein most likely to be myoglobin is protein (A or B)? - ANSWER (1) protein A (2)
protein A (3) protein B (4) protein A (5) protein B (6) protein A
*Refer to image
, In one type of hemoglobin mutant the amino acid change eliminates a hydrogen bond that
normally stabilizes the R state. Would you expect this mutant hemoglobin to have a higher or
lower O2 affinity compared to the normal protein and why? - ANSWER Lower O2 affinity
because the R-T equilibrium would be mostly shifted to the T state.
What is the effect of pH on O2 binding in the lungs compared to the tissues and why? - ANSWER
The correct answer is not given.
A transporter protein transports Ca2+ ions across a membrane at 37 °C in a cell in which the
membrane potential is 100 mV (inside of the cell is negative relative to the outside) and the
Ca2+ ion concentrations are 150 mM inside and 15 mM outside.
What is the DG when transporting 2 Ca2+
from the inside to the outside of the cell? - ANSWER +26.2 kJ/mol
A transporter protein transports Ca2+ ions across a membrane at 37 °C in a cell in which the
membrane potential is 100 mV (inside of the cell is negative relative to the outside) and the
Ca2+ ion concentrations are 150 mM inside and 15 mM outside.
What is the DG when transporting 2 Ca2+
from the outside of the cell to the inside of the cell? - ANSWER -26.2 kJ/mol
The solute concentration and the membrane potential each contribute to the total energy
requirement for transport. Based on your DG calculations above, which direction of transport
would be more energetically favorable (-DG) under the same conditions of solute concentration
and membrane potential if 2 glucose molecules were transported across the membrane rather
than 2 Ca2+ ions and why? - ANSWER Inside to Outside is more favorable because solute
concentration flows down the gradient.
