Myoglobin and Hemoglobin: Structure and Function

Flashcards covering the structure and function of myoglobin and hemoglobin, including key concepts such as the Bohr effect, BPG influence, CO2 transportation, mutations affecting hemoglobin, and physiological responses.

What is the Bohr effect?

The physiological observation that O2 binding affinity of hemoglobin decreases in the tissues due to higher [CO2] and lower pH.

How does pH affect hemoglobin's affinity for oxygen?

Increased H+ (lower pH) favors the T state of hemoglobin, decreasing its affinity for O2.

What role does carbonic anhydrase play in CO2 transport?

It catalyzes the hydration of CO2 to bicarbonate, facilitating CO2 transport from tissues to lungs.

What type of molecule is 2,3-bisphosphoglycerate (BPG) and what is its effect on hemoglobin?

BPG is an allosteric modulator that reduces hemoglobin's affinity for oxygen.

What is the difference in BPG affinity between fetal hemoglobin and adult hemoglobin?

Fetal hemoglobin has a lower affinity for BPG than adult hemoglobin, allowing it to have a higher affinity for O2.

What mutation causes sickle cell anemia?

A single amino acid substitution (Glu6 to Val6) in the β chain of hemoglobin produces a hydrophobic patch that leads to sickling of red blood cells.

How does being in a high altitude affect BPG levels?

BPG levels increase at high altitudes, decreasing hemoglobin's affinity for O2 and improving O2 release to tissues.

What effect does CO2 have on oxygen binding to hemoglobin?

CO2 binding to hemoglobin promotes the release of O2, favoring the deoxy form.

How does the binding of H+ influence the release of oxygen from hemoglobin?

H+ binding stabilizes the T state of hemoglobin, which favors O2 release.

Why is it important for hemoglobin to release O2 in metabolizing tissues?

Actively metabolizing tissues produce CO2 and H+, creating conditions that favor O2 release from hemoglobin.