6 Flashcards
Normal adult hemoglobin has
A. two alpha and two delta chains
B. three alpha and one beta chains
C. two alpha and two beta chains
D. two beta and two epsilon chains
C. two alpha and two beta chains
The number of heme groups in a hemoglobin molecule is
A. 1
B. 2
C. 3
D. 4
D. 4
Most defects in the hemoglobin molecule are related to
A. amino acid substitutions
B. diminished production of one of the polypeptide chains
C. homozygous A/A inheritance
D. either A or and B
D. either A or and B
The correct molecular composition of hemoglobin is
A. four heme groups two α and two ß globin chains
B. four heme groups, four α globin chains
C. two heme groups, four ß globin chains
D. two heme groups, one α and one ß globin chains
A. four heme groups two α and two ß globin chains
Increased amounts of 2,3-DPG _____ the oxygen affinity of the hemoglobin molecule.
A. increase
B. decrease
C. do not alter
B. decrease
After a molecule of hemoglobin gains the first two oxygen molecules, the molecule
A. expels 2,3-DPG
B. has decreased oxygen affinity
C. becomes saturated with oxygen
D. adds a molecule of oxygen to an alpha chain
A. expels 2,3-DPG
If normal adult (A1) and fetal hemoglobin F are compared, fetal hemoglobin has _____ affinity for oxygen.
A. less
B. the same
C. a greater
C. a greater
Oxyhemoglobin is a _____ than deoxyhemoglobin.
A. weaker acid
B. stronger acid
B. stronger acid
If a young male was preparing for olympic competition and had his blood drawn for the measurement of oxygen dissociation, his results would demonstrate
A. a shift to the right
B. a shift to the left
C. no deviation from a normal curve
D. no results could be recorded
A. a shift to the right
In cases of chronic carboxyhemoglobin exposure, the patient’s oxygen dissociation curve would exhibit
A. a shift to the left
B. a shift to the right
C. decreased affinity for oxygen
D. a normal curve
A. a shift to the left
Heme is synthesized predominantly in
A. the liver
B. the red bone marrow
C. the mature erythrocytes
D. both A and B
D. both A and B
The upper limit of the reference range of hemoglobin in an adult male is
A. 10.5 to 12.0 g/dL
B. 12.5 to 14.0 g/dL
C. 13.5 to 15.0 g/dL
D. 14 to 18.0 g/dL
D. 14 to 18.0 g/dL
When iron availability is depleted in a cell, the translational rates of ferritin mRNA is
A. increased oxygen affinity
B. decreased oxygen affinity
C. no effect on oxygen affinity
D. 2,3-DPG will enter the center cavity of the hemoglobin molecule
B. decreased oxygen affinity
The protein responsible for the transport of iron in hemoglobin synthesis is
A. globin
B. transferrin
C. oxyhemoglobin
D. ferritin
B. transferrin
If globin synthesis is insufficient in a person, iron accumulates in the cell as _____ aggregates.
A. transferrin
B. ferritin
C. albumin
D. heme
B. ferritin
Questions 16 and 17: The initial condensation reaction in the synthesis of porphyrin preceding heme formation takes place in the (16) _____ and requires (17) _____.
- A. liver
B. spleen
C. red bone marrow
D. mitochondria - A. iron
B. vitamin B6
C. vitamin B12
D. vitamin D
- D. mitochondria
- B. vitamin B6
The final steps in heme synthesis, including the formation of protoporphyrin, take place in
A. a cell’s nucleus
B. a cell’s cytoplasm
C. the spleen
D. the mitochondria
D. the mitochondria
The dark-staining granules in the red blood cells when a bone marrow smear stained with Prussian Blue stain is examined
represent a defect of
A. membrane development
B. hemoglobin synthesis
C. globulin synthesis
D. red blood cell aging
B. hemoglobin synthesis
The child’s medical history and the appearance of dense, dark-staining particles in some of the red blood cells on a peripheral blood smear suggest a diagnosis of
A. iron deficiency anemia
B. malaria
C. ingestion of lead
D. sickle cell disease
C. ingestion of lead
The major hemoglobin synthesized in the second trimester fetus is
A. A
B. F
C. A2
D. A1c
B. F
Which of the following hemoglobin types is the major type present in a normal adult?
A. A
B. S
C. A2
D. A1c
A. A
Hemoglobin A consists of
A. two alpha and two delta chains
B. zeta chains and either epsilon or gamma chains
C. two alpha and two beta chains
D. two alpha and two gamma chains
C. two alpha and two beta chains
Hemoglobin A2 consists of
A. two alpha and two delta chains
B. zeta chains and either epsilon or gamma chains
C. two alpha and two beta chains
D. two alpha and two gamma chains
A. two alpha and two delta chains
Hemoglobin F consists of
A. two alpha and two delta chains
B. zeta chains and either epsilon or gamma chains
C. two alpha and two beta chains
D. two alpha and two gamma chains
D. two alpha and two gamma chains
Embryonic hemoglobin consists of
A. two alpha and two delta chains
B. zeta chains and either epsilon or gamma chains
C. two alpha and two beta chains
D. two alpha and two gamma chains
B. zeta chains and either epsilon or gamma chains
In normal infants, fetal hemoglobin (hemoglobin F) persists until
A. a few days after birth
B. a few weeks after birth
C. several months after birth
D. adulthood
C. several months after birth
After a man was found unconscious in his garage with the car motor running, he was transported to the emergency department. When blood was drawn for a complete blood count, the plasma was noted to be bright red. What kind of variant hemoglobin should be suspected?
A. Hemoglobin F
B. Hemoglobin A
C. Methemoglobin
D. Carboxyhemoglobin
D. Carboxyhemoglobin
Heinz bodies are associated with
A. hemoglobin F
B. hemoglobin A
C. sulfhemoglobin
D. carboxyhemoglobin
C. sulfhemoglobin
A characteristic of methemoglobin is that it is
A. incapable of combining with oxygen
B. incapable of combining with carbon dioxide
C. susceptible to precipitation as Heinz bodies
D. present in normal in vivo concentration of greater than 15%
A. incapable of combining with oxygen
Altered solubility of the hemoglobin S molecule is due to
A. substitution of a nonpolar amino acid residue for a polar residue near the surface of the chain
B. substitution of a polar amino acid residue for a nonpolar residue near the surface of the chain
C. replacement of glutamic acid amino acid residue at the sixth position on the β-globin chain by a lysine amino acid residue
D. replacement of lysine amino acid residue at the sixth position on the β-globin chain by a glutamic acid amino acid residue
A. substitution of a nonpolar amino acid residue for a polar residue near the surface of the chain
The sickle gene may commonly occur with hemoglobin____.
A. C
B. F
C. Bart
D. H
C. Bart
The alkaline denaturation test detects the presence of hemoglobin
A. A1C
B. F
C. C
D. S
B. F
The type of hemoglobin that is detectable with the Kleihauer-Betke test is
A. A
B. A2
C. F
D. S
C. F
The physical difference in the detectable type of hemoglobin in the
Kleihauer-Betke test is that this form of hemoglobin
A. resists denaturation in the procedure
B. is denatured in the procedure
C. lacks gamma globulin genes
D. has a lower affinity for oxygen
A. resists denaturation in the procedure
Cellulose acetate at pH 8.6 separates the hemoglobin fractions
A. S
B. H
C. A
D. both A and C
D. both A and C
As the erythrocyte ages,
A. the membrane becomes less flexible with loss of cell membrane
B. cellular hemoglobin increases
C. enzyme activity, particularly glycolysis, decreases
D. all of the above
D. all of the above
Erythrocytic catabolism produces the disassembling of hemoglobin followed by
A. iron transported in the plasma by transferrin
B. globin catabolized in the liver to amino acids and then entering the amino acid pool
C. bilirubin formed from opened porphyrin ring and carried by plasma albumin to the liver, conjugated, and excreted in bile
D. all of the above
D. all of the above
Which of the following statements are true of the intravascular destruction of erythrocytes?
A. It accounts for less than 10% of normal erythrocyte breakdown.
B. Hemoglobin is released directly into blood.
C. Alpha and beta dimers are bound to haptoglobin.
D. All of the above.
D. All of the above.
If a female patient is diagnosed with anemia and her follow-up assays indicate blood serum results of increased bilirubin and decreased haptoglobin with hemosiderin in her urinary sediment, what is the most probable diagnosis?
A. Extravascular catabolism
B. Intravascular catabolism
C. Defective hemoglobin synthesis
D. Thalassemia
B. Intravascular catabolism
