Which of the following is true about glucose reabsorption from the tubular lumen to the tubular cell?

Correct Answer: D

Rationale: Glucose reabsorption from lumen to cell is secondary active transport SGLT uses Na gradient (e.g., PCT), energy-dependent. Passive transport lacks energy false. Downhill misaligns against gradient. No energy contradicts mechanism incorrect. Sodium-coupled active transport distinguishes it, critical for glucose recovery, unlike passive or energy-free errors.

Correct Answer: D

Rationale: Na absorption in ascending Loop is active in thick (Na /K /2Cl⁻ cotransport) and passive in thin (e.g., gradient-driven). All passive ignores thick's pump false. All active overstates thin incorrect. Reversed activity misaligns thick is active. Dual mechanism distinguishes it, critical for concentration gradient, unlike uniform or swapped errors.

Correct Answer: D

Rationale: Normal adult blood pH is 7.35-7.45 tightly regulated (e.g., bicarbonate buffer). 7.45-7.8 is alkalosis abnormal. 6.8-7.35 includes acidosis too broad. 6.8-6.8 is lethal false. Narrow range distinguishes it, critical for homeostasis, unlike wide or extreme ranges.

Correct Answer: C

Rationale: H binds HCO₃⁻ first forms H₂CO₃, then splits to CO₂/H₂O (e.g., buffering sequence). H₂CO₃ to CO₂ is second not initial. HCO₃⁻ to H₂CO₃ reverses H drives. All in order missequences false. Binding start distinguishes it, critical for buffer mechanics, unlike subsequent or reversed steps.

Correct Answer: B

Rationale: The nephron (filtration to urine formation) is the kidney's functional unit not glomerulus (filtration site), ureter (transport), or Bowman's capsule (nephron part). This identifies the kidney's workhorse, critical for physiology, contrasting with its parts.