Structurally, myoglobin and hemoglobin are very similar proteins. In
which of the following levels of structure do they differ most?
Tertiary structure.
Quaternary structure.
Primary structure.
Secondary structure.
Quaternary structure.
Myoglobin does not have quaternary structure whereas hemoglobin does.
Which of the following statements is FALSE? In its interaction with
hemoglobin, oxygen is:
reversibly bound.
homoallosteric effector.
a prosthetic group.
bound at the 6th coordination position of the Fe(II) ion in the heme.
a ligand.
a prosthetic group.
,Which of the following amino acids has the most significant role in
the molecular mechanisms of hemoglobin's function?
glycine
tyrosine
histidine
lysine
glutamate
histidine
Histidine residues play several critical roles in hemoglobin function.
For example, think of the proximal histidine, the distal histidine,
and the histidine residues involved in the binding of 2,3-
bisphosphoglycerate (BPG).
Which of the following statements about 2,3-bisphosphoglycerate (BPG)
binding is FALSE?
BPG binds less tightly to fetal hemoglobin than to adult hemoglobin,
thereby aiding oxygen transfer to a fetus.
BPG binds to hemoglobin at one site and lowers hemoglobin's affinity
for oxygen at another site.
BPG aids oxygen delivery to tissues by increasing the affinity of
myoglobin for oxygen.
BPG requires a binding site containing multiple positively charged
groups.
BPG aids oxygen delivery to tissues by increasing the affinity of
myoglobin for oxygen.
,This statement is false. BPG does not affect the affinity of
myoglobin for oxygen.
Fetal hemoglobin has a higher affinity for oxygen than maternal
hemoglobin. Which of the following statements correctly outlines the
mechanism behind this observation?
In fetal hemoglobin, the residue Ser143 is mutated to His143, and so
the protein binds BPG with lower affinity.
In fetal hemoglobin, the residue His143 is mutated to Ser143, and so
the protein binds BPG with lower affinity.
In fetal hemoglobin, the residue Ser143 is mutated to His143, and so
the protein binds BPG with greater affinity.
In fetal hemoglobin, the residue His143 is mutated to Ser143, and so
the protein binds BPG with greater affinity.
In fetal hemoglobin, the residue His143 is mutated to Ser143, and so
the protein binds BPG with lower affinity.
The mutation of His143 to Ser143 reduces the number of positively
charged groups available to form salt bridges with BPG. This reduces
the affinity of hemoglobin for BPG and thus the T (low-affinity)
state of hemoglobin is less stable.
Which of the following statements correctly describes the interaction
between an allosteric protein and an allosteric effector?
The effector binds non-specifically to one subunit and through
induced fit initiates cooperativity between the subunits.
The effector binds reversibly at a specific site on one subunit of
the protein, causing a global change in conformation.
The effector activates the protein by causing it to switch from its T
(low affinity) to R (high affinity) form.
, The effector binds covalently at a specific site on the protein,
causing a global change in shape.
The effector binds reversibly at a specific site on one subunit of
the protein, causing a global change in conformation.
Which of the following statements about sickle cell anemia is FALSE?
In sickle cell anemia, hemoglobin molecules aggregate to form long
fibers that distort the shape of the red blood cell.
The mutation in sickle cell anemia replaces a hydrophilic surface
residue with a non-polar residue.
Sickle cell anemia is a consequence of a conservative mutation in the
β-globin gene.
Sickle cell anemia is a genetic disease.
Sickle cell anemia is a consequence of a conservative mutation in the
β-globin gene.
A mutation that significantly affects the folding or function of a
protein cannot be considered conservative
Which of the following triggers the transition from T state to R
state (low to high affinity) in hemoglobin?
oxygen binding.
oxygen dissociation.
subunit dissociation.
movement of the proximal histidine.
heme binding.
oxygen binding.
which of the following levels of structure do they differ most?
Tertiary structure.
Quaternary structure.
Primary structure.
Secondary structure.
Quaternary structure.
Myoglobin does not have quaternary structure whereas hemoglobin does.
Which of the following statements is FALSE? In its interaction with
hemoglobin, oxygen is:
reversibly bound.
homoallosteric effector.
a prosthetic group.
bound at the 6th coordination position of the Fe(II) ion in the heme.
a ligand.
a prosthetic group.
,Which of the following amino acids has the most significant role in
the molecular mechanisms of hemoglobin's function?
glycine
tyrosine
histidine
lysine
glutamate
histidine
Histidine residues play several critical roles in hemoglobin function.
For example, think of the proximal histidine, the distal histidine,
and the histidine residues involved in the binding of 2,3-
bisphosphoglycerate (BPG).
Which of the following statements about 2,3-bisphosphoglycerate (BPG)
binding is FALSE?
BPG binds less tightly to fetal hemoglobin than to adult hemoglobin,
thereby aiding oxygen transfer to a fetus.
BPG binds to hemoglobin at one site and lowers hemoglobin's affinity
for oxygen at another site.
BPG aids oxygen delivery to tissues by increasing the affinity of
myoglobin for oxygen.
BPG requires a binding site containing multiple positively charged
groups.
BPG aids oxygen delivery to tissues by increasing the affinity of
myoglobin for oxygen.
,This statement is false. BPG does not affect the affinity of
myoglobin for oxygen.
Fetal hemoglobin has a higher affinity for oxygen than maternal
hemoglobin. Which of the following statements correctly outlines the
mechanism behind this observation?
In fetal hemoglobin, the residue Ser143 is mutated to His143, and so
the protein binds BPG with lower affinity.
In fetal hemoglobin, the residue His143 is mutated to Ser143, and so
the protein binds BPG with lower affinity.
In fetal hemoglobin, the residue Ser143 is mutated to His143, and so
the protein binds BPG with greater affinity.
In fetal hemoglobin, the residue His143 is mutated to Ser143, and so
the protein binds BPG with greater affinity.
In fetal hemoglobin, the residue His143 is mutated to Ser143, and so
the protein binds BPG with lower affinity.
The mutation of His143 to Ser143 reduces the number of positively
charged groups available to form salt bridges with BPG. This reduces
the affinity of hemoglobin for BPG and thus the T (low-affinity)
state of hemoglobin is less stable.
Which of the following statements correctly describes the interaction
between an allosteric protein and an allosteric effector?
The effector binds non-specifically to one subunit and through
induced fit initiates cooperativity between the subunits.
The effector binds reversibly at a specific site on one subunit of
the protein, causing a global change in conformation.
The effector activates the protein by causing it to switch from its T
(low affinity) to R (high affinity) form.
, The effector binds covalently at a specific site on the protein,
causing a global change in shape.
The effector binds reversibly at a specific site on one subunit of
the protein, causing a global change in conformation.
Which of the following statements about sickle cell anemia is FALSE?
In sickle cell anemia, hemoglobin molecules aggregate to form long
fibers that distort the shape of the red blood cell.
The mutation in sickle cell anemia replaces a hydrophilic surface
residue with a non-polar residue.
Sickle cell anemia is a consequence of a conservative mutation in the
β-globin gene.
Sickle cell anemia is a genetic disease.
Sickle cell anemia is a consequence of a conservative mutation in the
β-globin gene.
A mutation that significantly affects the folding or function of a
protein cannot be considered conservative
Which of the following triggers the transition from T state to R
state (low to high affinity) in hemoglobin?
oxygen binding.
oxygen dissociation.
subunit dissociation.
movement of the proximal histidine.
heme binding.
oxygen binding.
