Solved UPSC CDS/OTA Question
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Q · Excretory Systemmedium · 45s
Which ion’s reabsorption is directly coupled to bicarbonate reclamation in the proximal tubule?
TopicExcretory System
Question Typemultiple choice
Difficultymedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
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Na⁺/H⁺ exchangers reabsorb Na⁺ into the cell in exchange for H⁺ secretion. The secreted H⁺ combines with filtered HCO₃⁻ to form CO₂ and H₂O, which diffuse back into the cell for HCO₃⁻ regeneration and basolateral transport along with Na⁺.
Final Answer: Option A - Na⁺