UPSC NDA I 2017 General Ability Solved Paper

Concept:The kidney secretes $\mathrm{Renin}$, an enzyme that converts the plasma protein $\mathrm{angiotensinogen}$ into $\mathrm{angiotensin\ I}$, initiating a blood pressure regulation cascade.Explanation:Renin is released by juxtaglomerular cells in the kidney.It cleaves $\mathrm{angiotensinogen}$ (produced by the liver) to form $\mathrm{angiotensin\ I}$.Angiotensin I is then converted to $\mathrm{angiotensin\ II}$ by angiotensin-converting enzyme (ACE).Angiotensin II raises blood pressure via vasoconstriction and aldosterone secretion.Among the options:$\mathrm{Nitrogenase}$ fixes atmospheric nitrogen into ammonia — unrelated to this process.$\mathrm{Hydrolase}$ and $\mathrm{Mono-oxygenase}$ are broad enzyme classes, not specific to angiotensinogen conversion.Thus, the correct enzyme is $\mathrm{Renin}$.Answer:Renin (Option A).