CO2 Transport in Blood and Hemoglobin Interactions

Steps:

• Recall that CO2 is transported in blood as dissolved gas, bicarbonate ions, and carbaminohemoglobin.
• Evaluate each statement against known physiological processes: CO2 binding to hemoglobin, enzyme roles, and gas exchange.
• Identify the statement accurately describing carbonic anhydrase's function in catalyzing CO2 hydration.
• Confirm B as correct by verifying it matches the enzyme's role in forming carbonic acid.

Why B is correct:

• Carbonic anhydrase catalyzes the reaction CO2 + H2O ⇌ H2CO3 (carbonic acid), speeding up bicarbonate formation for CO2 transport.

Why the others are wrong:

• A: CO2 combines with hemoglobin's amino groups, not directly with hemoglobin itself, to form carbaminohaemoglobin.
• C: At lungs, CO2 is released as bicarbonate converts to CO2 via the reverse reaction, not carbonic acid and water reacting.
• D: Higher CO2 concentration decreases hemoglobin's oxygen affinity (Bohr effect), not increases it.

Final answer: B