1.32: Hemoglobin

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The primary structure of the hemoglobin molecule is:
1. the heme group
2. two \(\alpha\) and \(\beta\) two chains
3. the folding sequence
4. the amino acid sequence
5. the globin portion
The globin portion of the hemoglobin A molecule is comprised of:
1. four polypeptide chains
2. a porphyrin group and polypeptide chains
3. the \(\Gamma\) chain (\(\Gamma\) globin)
4. the \(\alpha\) helical structure
5. heme and \(\alpha\) plus \(\beta\) chains
Each of the heme molecules in hemoglobin can bind ____molecule (s) of oxygen?
1. one
2. two
3. three
4. four
5. five
The affinity of oxygen for hemoglobin does NOT depend on:
1. oxygen content (saturation) of hemoglobin
2. partial pressure of oxygen
3. 2, 3 diphosphoglycerate concentration in the red blood cell
4. temperature
5. number of polypeptide chains
The oxygen dissociation curve is graphed by plotting which parameters?
1. O₂ Hb saturation vs. pH
2. O₂ Hb saturation vs. arterial blood pCO₂
3. O₂ Hb saturation versus oxygen tension (PO₂)
4. O₂ Hb unsaturation (dissociation) versus pH
5. O₂ Hb unsaturation (dissociation) versus arterial blood pCO₂
The Bohr effect:
1. is conventionally indexed by the P50 value
2. reflects 2, 3 diphosphoglycerate concentration
3. is plotted as a function of temperature versus pH
4. expresses the fact that the oxygen affinity of hemoglobin varies with pH
5. is usually determined by measuring the temperature and the 2, 3 diphosphoglycerate ratio
Methemoglobin is:
1. hemoglobin combined with carbon monoxide
2. hemoglobin combined with methionine
3. hemoglobin combined with heavy metals
4. oxidized hemoglobin
5. un-oxidized hemoglobin
Match the hemoglobin name and structure:

adult Hb A
adult Hb A2
fetal Hb F
embryonic Grower I
embryonic Grower II

\(\zeta_{2} \epsilon_{2}\)
\(\alpha_{2} \epsilon_{2}\)
\(\alpha_{2} \gamma_{2}\)
\(\alpha_{2} \beta_{2}\)
\(\alpha_{2} \delta_{2}\)

At birth the major circulating hemoglobin is usually:
1. Adult Hb A
2. Methemoglobin
3. Embryonic hemoglobin
4. Adult Hb A2
5. Fetal hemoglobin
Which of the following is not a molecular mechanism responsible for structural hemoglobin variants?
1. amino acid substitution
2. deletions and insertions of DNA
3. unequal crossing over of DNA
4. chain elongation
5. denaturation of polypeptide chains
Sickle cell hemoglobin is the result of:
1. substitution at position 6 (valine for glutamine)
2. substitution at position 6 (lysine for glutamine)
3. denaturation of the hemoglobin outside the cell to form red blood cell sickles
4. puncturing of the plasma cell membrane (pop sickle)
5. variation in chain elongation of the Hb A molecule (Hb A to Hb F)
Sickle cells cause pathophysiologic problems because:
1. they block microcirculation
2. they gel and precipitate
3. they cause acidosis
4. they are larger than normal red cells
5. they are double membraned cells
Thalassemias are inherited hemoglobinopathies characterized as:
1. specific amino acid substitutions
2. decreased production of globin chain(s)
3. abnormal structure of specific chains
4. elongation of the chain polypeptide
5. deletion of several amino acids
Methemoglobinemia can be caused by all but one of the following:
1. drugs
2. chemicals
3. amino acid substitutions
4. deficiency of methemoglobin reducing ability of red cells
5. white cell amino acid substitution
Which of the following does NOT affect blood levels of hemoglobin?
1. age
2. gender
3. physical exercise
4. posture
5. race
In which of the following groups is the carboxyhemoglobin elevated to abnormal levels of 4% to 20% compared to the healthier 0.2 to 0.8%?
1. residents of Los Angeles
2. individuals whose heme is degraded to bilirubin
3. factory workers
4. smokers
5. laboratory workers
Oxygen saturation is used clinically to determine:
1. tissue hypoxia or hyperoxia
2. oxygen affinity
3. anemia
4. erythopoietin stimulating effect of hypoxia
5. polycythemia

Answer

d (p. 677-678)
a (p. 677)
a (p. 679)
e (p. 680-681)
c (p. 680)
d (p. 680-681)
d (p. 682)
1-d, 2-e, 3-c (p. 677-679), 4-a , 5-b
b (p. 688-689)
e (p. 682, 690)
e (p. 690-691)
d (p. 691)
b (p. 688-689)
e (p. 682, 690)
e (p. 690-691)
d (p. 691)
a (p. 691)