BIOC 384 – D2Q 1–3 Miesfeld Study Guide with Reviewed Answers | 2025 Update

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BIOC 384 – D2Q 1–3 Miesfeld Study Guide
with Reviewed Answers | 2025 Update


1. The fractional saturation of hemoglobin (Hb) binding to oxygen is illustrated
by______________.

A) [HbO2] / ([HbO2] + [Hb]).
B) ([HbO2] + [Hb]) / [HbO2].
C) [HbO2] / [Hb].
D) [Hb] / [HbO2]. - ANSWER A) [HbO2] / ([HbO2] + [Hb]).

2. Consider the following interaction between a protein and its ligand: [P] + [L]
[PL].If [L] = 5 mM, [P] = 3 mM, and [PL] = 2 mM, what is the dissociation
constant?

A) 15 mM
B) 7.5 mM
C) 0.2 mM
D) 0.133 mM
E) 0.4 mM - ANSWER B) 7.5 mM

3. 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 and
choose the set of all correct answers.

1. True / False - Protein sequencing by ED does not require purified protein but
sequencing by MS does.

2. True / False - The N-terminal residue removed by acid treatment in ED is
always a methionine.

3. True / False - Trypsin and chymotrypsin treatment often provides identical
peptide fragments for ED.

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4. True / False - Genomic sequences are needed to predict protein sequences by the
MS method.

5. True / False - Trypsin treatment provides useful sequence information when
analyzing data from MS.

A) (1) True (2) True (3) False (4) False (5) True

4. For reversible binding between a protein and a ligand,______________.

a) the larger the Kd, the higher the affinity between the protein and ligand.
b) the units for Kd are M-1.
c) the larger the Ka, the higher the affinity between the protein and ligand.
d) Ka is equal to Kd. - ANSWER c) the larger the Ka, the higher the affinity
between the protein and ligand.

5. Oxygen binding is monitored for a solution of hemoglobin. During the
experiment, the curve changes from sigmoidal to hyperbolic. Which of the
following may be the reason for the change?

a) A negative allosteric effector was added.
b) A positive allosteric effector was added.
c) 2,3-bisphosphoglycerate levels increased.
d) The protein was denatured.
e) The protein dissociated into individual subunits. - ANSWER e) The protein
dissociated into individual subunits.

6. In isoelectric focusing, a protein that is initially located in the pH gradient
that is below the pI of the protein would_______________.

a) stop migrating.
b) migrate toward the anode.
c) precipitate out of solution.
d) migrate, but there is no way to determine the direction.
e) migrate toward the cathode. - ANSWER e) migrate toward the cathode.

7. Using SDS gel electrophoresis to separate proteins, _________ proteins
migrate the fastest in the gel and move farther away from the ___________
because of their _________ charge.

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a) large; cathode; positive
b) small; anode; negative
c) small; cathode; negative
d) large; cathode; negative
e) large; anode; negative - ANSWER c) small; cathode; negative

8. A polypeptide was digested by trypsin and chymotrypsin. Use the following
information to determine the polypeptide sequence.

TRYPSIN DIGEST:

LMYK
MGFCE
WDER

CHYMOTRYPSIN DIGEST:

CE
LMYKW
DERMGF

a) LMYKWMGFCEDER
b) LMYKWDERMGFCE
c) CELMYKWDERMGF
d) ECFGMREDWKYLM - ANSWER

9. Which of the following is a positive effector for oxygen binding to
hemoglobin?

a) CO
b) CO2
c) 2,3-bisphosphoglycerate
d) O2
e) H+ - ANSWER d) O2

10.Match each major class of protein with the best representative protein from
each class.

1. Structural proteins
2. Genomic caretaker proteins

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3. Metabolic enzymes
4. Transport proteins
5. Cell signaling proteins

______ Aquaporin - ANSWER 4. Transport proteins

11.Match each major class of protein with the best representative protein from
each class.

1. Structural proteins
2. Genomic caretaker proteins
3. Metabolic enzymes
4. Transport proteins
5. Cell signaling proteins

______ Actin - ANSWER 1. Structural proteins

12.Match each major class of protein with the best representative protein from
each class.

1. Structural proteins
2. Genomic caretaker proteins
3. Metabolic enzymes
4. Transport proteins
5. Cell signaling proteins

______ Pepsin - ANSWER 3. Metabolic enzymes

13.Match each major class of protein with the best representative protein from
each class.

1. Structural proteins
2. Genomic caretaker proteins
3. Metabolic enzymes
4. Transport proteins
5. Cell signaling proteins

______ Histone - ANSWER 2. Genomic caretaker proteins