1.32: Hemoglobin
- Page ID
- 38612
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- The primary structure of the hemoglobin molecule is:
- the heme group
- two \(\alpha\) and \(\beta\) two chains
- the folding sequence
- the amino acid sequence
- the globin portion
- The globin portion of the hemoglobin A molecule is comprised of:
- four polypeptide chains
- a porphyrin group and polypeptide chains
- the \(\Gamma\) chain (\(\Gamma\) globin)
- the \(\alpha\) helical structure
- heme and \(\alpha\) plus \(\beta\) chains
- Each of the heme molecules in hemoglobin can bind ____molecule (s) of oxygen?
- one
- two
- three
- four
- five
- The affinity of oxygen for hemoglobin does NOT depend on:
- oxygen content (saturation) of hemoglobin
- partial pressure of oxygen
- 2, 3 diphosphoglycerate concentration in the red blood cell
- temperature
- number of polypeptide chains
- The oxygen dissociation curve is graphed by plotting which parameters?
- O2 Hb saturation vs. pH
- O2 Hb saturation vs. arterial blood pCO2
- O2 Hb saturation versus oxygen tension (PO2)
- O2 Hb unsaturation (dissociation) versus pH
- O2 Hb unsaturation (dissociation) versus arterial blood pCO2
- The Bohr effect:
- is conventionally indexed by the P50 value
- reflects 2, 3 diphosphoglycerate concentration
- is plotted as a function of temperature versus pH
- expresses the fact that the oxygen affinity of hemoglobin varies with pH
- is usually determined by measuring the temperature and the 2, 3 diphosphoglycerate ratio
- Methemoglobin is:
- hemoglobin combined with carbon monoxide
- hemoglobin combined with methionine
- hemoglobin combined with heavy metals
- oxidized hemoglobin
- un-oxidized hemoglobin
- Match the hemoglobin name and structure:
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- At birth the major circulating hemoglobin is usually:
- Adult Hb A
- Methemoglobin
- Embryonic hemoglobin
- Adult Hb A2
- Fetal hemoglobin
- Which of the following is not a molecular mechanism responsible for structural hemoglobin variants?
- amino acid substitution
- deletions and insertions of DNA
- unequal crossing over of DNA
- chain elongation
- denaturation of polypeptide chains
- Sickle cell hemoglobin is the result of:
- substitution at position 6 (valine for glutamine)
- substitution at position 6 (lysine for glutamine)
- denaturation of the hemoglobin outside the cell to form red blood cell sickles
- puncturing of the plasma cell membrane (pop sickle)
- variation in chain elongation of the Hb A molecule (Hb A to Hb F)
- Sickle cells cause pathophysiologic problems because:
- they block microcirculation
- they gel and precipitate
- they cause acidosis
- they are larger than normal red cells
- they are double membraned cells
- Thalassemias are inherited hemoglobinopathies characterized as:
- specific amino acid substitutions
- decreased production of globin chain(s)
- abnormal structure of specific chains
- elongation of the chain polypeptide
- deletion of several amino acids
- Methemoglobinemia can be caused by all but one of the following:
- drugs
- chemicals
- amino acid substitutions
- deficiency of methemoglobin reducing ability of red cells
- white cell amino acid substitution
- Which of the following does NOT affect blood levels of hemoglobin?
- age
- gender
- physical exercise
- posture
- 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%?
- residents of Los Angeles
- individuals whose heme is degraded to bilirubin
- factory workers
- smokers
- laboratory workers
- Oxygen saturation is used clinically to determine:
- tissue hypoxia or hyperoxia
- oxygen affinity
- anemia
- erythopoietin stimulating effect of hypoxia
- 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)