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Essential Biochemistry - Chemistry Of Hemoglobin (Section 3)

1
What is the role of histidines in hemoglobin function?
Answer
(C)
To coordinate the iron atom
2
The following are true about the structure of hemoglobin:
Answer
A
B
C
3
Which of the following statements is true regarding the R form of hemoglobin?
Answer
(C)
Oxygen is readily bound.
4
What happens to the oxygen-hemoglobin dissociation curve when pH decreases?
Answer
(B)
It shifts to the right.
5
What is the normal ratio of HbA to HbA2 in an adult?
Answer
(A)
97:3
6
What is the function of the globin chains in hemoglobin?
Answer
(C)
To protect the heme group and facilitate oxygen binding.
7
Which condition is characterized by the reduced ability of hemoglobin to carry oxygen?
Answer
(B)
Anemia
8
Which factor decreases the affinity of hemoglobin for oxygen?
Answer
(B)
Increased CO₂ concentration
9
What is the role of 2,3-Bisphosphoglycerate (2,3-BPG) in red blood cells?
Answer
(B)
It decreases the binding affinity of hemoglobin for oxygen.
10
What is the primary function of hemoglobin in red blood cells?
Answer
(B)
To transport oxygen throughout the body.
11
What is the normal percentage of HbA in an adult?
Answer
(C)
Approximately 97%
12
Iron in heme is linked to globin through
Answer
(A)
Histidine
13
Which of the following conditions results from the inheritance of a single copy of the β-globin gene mutation?
Answer
(B)
β-thalassemia minor (trait)
14
What are the main causes that increase the binding affinity of oxygen with hemoglobin?
Answer
A
B
C
15
What are the factors that promote the release of oxygen from hemoglobin?
Answer
A
B
C
16
Which of the following is the primary function of the globin chains in hemoglobin?
Answer
(B)
Stabilize the heme group.
17
What is the primary function of the globin chains?
Answer
(C)
Stabilize the heme group
18
What is the correct term for the form of hemoglobin that is bound to carbon dioxide?
Answer
(B)
Carbaminohemoglobin
19
In the T (tense) form of hemoglobin, what interactions are most significant in stabilizing the molecule?
Answer
(B)
Hydrogen bonds, salt bridges, and Van der Waals interactions
20
What causes the sickling of red blood cells in sickle cell anemia?
Answer
(B)
A genetic mutation in the beta-globin gene.
21
What is the primary role of carbonic anhydrase in red blood cells?
Answer
(A)
To convert carbon dioxide into bicarbonate ions.
22
Which of the following is the best description of the quaternary structure of hemoglobin?
Answer
(B)
The arrangement of multiple polypeptide chains in a functional protein.
23
What is the primary effect of 2,3-bisphosphoglycerate (2,3-BPG) on oxygen binding?
Answer
(B)
It decreases oxygen binding affinity.
24
What causes the sickling of red blood cells in sickle cell anemia?
Answer
(B)
Abnormal hemoglobin (HbS) polymerizing under low oxygen conditions.
25
What is the primary function of 2,3-BPG?
Answer
(B)
To decrease the affinity of hemoglobin for oxygen
26
Which of the following does NOT describe the relationship between HbF and HbA?
Answer
(C)
HbF is the primary hemoglobin in adults.
27
Which of the following best describes the role of HbA2?
Answer
(B)
It is a minor form of hemoglobin in adults, often elevated in thalassemia.
28
Which of the following statements accurately describes the sickle cell trait?
Answer
(C)
Individuals with the trait are usually asymptomatic.
29
In which form of hemoglobin is the iron atom in the ferrous (Fe²⁺) state?
Answer
(D)
Reduced hemoglobin
30
What is the Bohr effect?
Answer
(B)
The effect of pH and CO₂ on oxygen binding to hemoglobin.
31
What is the significance of the sigmoidal shape of the oxygen-hemoglobin dissociation curve?
Answer
A
C
32
What are the main functions of hemoglobin?
Answer
A
B
C
33
Which of the following best describes the binding of oxygen to hemoglobin?
Answer
(B)
Allosteric binding
34
What is the primary difference between HbA and HbF?
Answer
(C)
HbF has a higher affinity for oxygen.
35
Which substance, when bound to hemoglobin, prevents oxygen transport?
Answer
(C)
Carbon Monoxide
36
Which of the following are derivatives of hemoglobin?
Answer
A
B
C
D
37
Which molecules can bind to the heme group in hemoglobin?
Answer
A
B
38
What is the role of the heme group in hemoglobin?
Answer
(B)
Binding oxygen
39
Which of the following conditions is characterized by the presence of methemoglobin?
Answer
(C)
Methemoglobinemia
40
What is the main cause of sickle cell anemia?
Answer
(A)
A genetic mutation affecting the beta-globin gene
41
Which of the following will shift the oxygen-hemoglobin dissociation curve to the right?
Answer
(C)
Increased temperature
42
What are the causes of a shift to the right of the oxygen-hemoglobin dissociation curve?
Answer
A
B
C
43
Which of the following is a characteristic of HbS?
Answer
(B)
It polymerizes under low oxygen conditions
44
The following are the normal forms of hemoglobin, except:
Answer
(D)
HbS
45
What is the role of iron in the heme group?
Answer
(B)
To bind to oxygen
46
What is the name of the disease caused by a genetic mutation that results in the production of abnormal hemoglobin (HbS)?
Answer
(C)
Sickle Cell Anemia
47
The iron atom in heme is directly coordinated to which molecule?
Answer
(C)
Histidine residue
48
What is the effect of increased CO₂ on the oxygen-hemoglobin dissociation curve?
Answer
(C)
Shift to the right
49
Which factors shift the oxygen-hemoglobin dissociation curve to the right (decrease oxygen affinity)?
Answer
A
B
C
D
50
What is the primary cause of alpha-thalassemia?
Answer
(B)
A mutation in the alpha-globin gene.