객관식
Which of the following factors affects an enzyme's ability to function as an acid or base catalyst?
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3. Acids and Bases
Acids and Bases
객관식
Which conditions would cause the oxygen-hemoglobin saturation curve to shift to the left?
A
Decreased temperature and increased levels
B
Decreased and increased levels
C
Increased temperature and increased levels
D
Increased and decreased levels
검증된 단계별 안내1
Understand the oxygen-hemoglobin saturation curve: This curve represents the relationship between the partial pressure of oxygen (pO2) and the percentage of hemoglobin saturated with oxygen. A leftward shift indicates increased affinity of hemoglobin for oxygen.
Identify factors affecting the curve: The main factors include pH (Bohr effect), CO2 levels, temperature, and 2,3-bisphosphoglycerate (2,3-BPG) levels. These factors influence hemoglobin's affinity for oxygen.
Analyze the effect of pH: An increase in pH (alkalosis) results in a leftward shift of the curve, as hemoglobin's affinity for oxygen increases. This is due to the Bohr effect, where higher pH reduces the release of oxygen from hemoglobin.
Consider CO2 levels: Decreased CO2 levels also cause a leftward shift. CO2 reacts with water to form carbonic acid, which dissociates into bicarbonate and hydrogen ions, lowering pH. Thus, lower CO2 levels result in higher pH, enhancing oxygen affinity.
Combine the effects: Increased pH and decreased CO2 levels both contribute to a leftward shift in the oxygen-hemoglobin saturation curve, indicating increased oxygen affinity of hemoglobin under these conditions.
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