Myoglobin vs Hemoglobin Structure and Function

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Which type of interactions are primarily responsible for the tertiary structure of myoglobin and hemoglobin?

Covalent interactions

Van der Waals interactions

Ionic interactions

Hydrophobic interactions (correct)

In the binding of oxygen to heme iron in hemoglobin, what is the state of iron that is important for this process?

Oxidized state

Reduced state

Ferrous state (correct)

Ferric state

Which molecule binds to both adult hemoglobin and fetal hemoglobin, affecting their oxygenation properties?

2,3-bisphosphoglycerate (correct)

Carbon monoxide

Oxygen

Carbon dioxide

What is the primary therapeutic approach for carbon monoxide poisoning due to its competitive interaction with oxygen in hemoglobin?

Administration of pure oxygen (B) Signup and view all the answers

Which factor does not affect the oxygenation of hemoglobin in the lungs and in the tissues?

Oxygen solubility in blood (A) Signup and view all the answers

What is the main chemical difference between hemoglobin and methemoglobin?

Heme group is bound reversibly to oxygen in hemoglobin but irreversibly in methemoglobin (D) Signup and view all the answers

What is the role of the distal histidine in myoglobin and hemoglobin?

It prevents oxidation of the iron ion to a higher oxidation state (A) Signup and view all the answers

Which statement describes the function of the proximal histidine in myoglobin and hemoglobin?

It binds directly to the iron in the heme group (B) Signup and view all the answers

What causes methemoglobin formation?

Oxidation of the iron ion from Fe2+ to Fe3+ (D) Signup and view all the answers

What is the role of heme in cytochromes?

It serves as an electron carrier (B) Signup and view all the answers

What is the primary function of myoglobin?

Releasing oxygen within muscle cells in response to oxygen demand (A) Signup and view all the answers

What does a lower P50 indicate for hemoglobin's affinity for oxygen?

Higher affinity for oxygen (C) Signup and view all the answers

Which of the following binds to hemoglobin in the T form, shifting the equilibrium between the R and T states toward the T form?

2,3-Bisphosphoglycerate (C) Signup and view all the answers

What is the primary effect of carbon monoxide poisoning on hemoglobin?

Increases the affinity of hemoglobin for oxygen (B) Signup and view all the answers

In what form does methemoglobin contain iron?

Ferric (Fe3+) (A) Signup and view all the answers

What is the main difference between alpha thalassemia and beta thalassemia?

Alpha thalassemia results in decreased expression of one of the four gene copies, while beta thalassemia results from a mutation in only one copy of the gene or incorrect splicing. (C) Signup and view all the answers

What is the abnormality associated with Hemoglobin Gun Hill?

Formation of unstable mutant hemoglobin associated with mild compensated hemolysis due to a deletion of five amino acids in the beta-chains. (B) Signup and view all the answers

In uncontrolled diabetes, what happens to the levels of HbA1c compared to normal?

HbA1c levels increase more than twice normal due to the generation of more HbA1c than normal. (D) Signup and view all the answers

What does hereditary persistence of fetal hemoglobin (HPFH) refer to?

Continued production of fetal hemoglobin (hemoglobin F) well into adulthood, disregarding the normal shutoff point after which only adult-type hemoglobin should be produced. (C) Signup and view all the answers

What is the impact of CO poisoning on hemoglobin?

CO poisoning reduces the ability of hemoglobin to bind oxygen and transport it to tissues. (B) Signup and view all the answers