Question: 120 Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R :
Assertion A : ATP is used at two steps in glycolysis.
Reason R : First ATP is used in converting glucose into glucose-6-phosphate and second ATP is used in conversion of fructose-6phosphate into fructose-1-6-diphosphate.
In the light of the above statements, choose the correct answer from the options given below :
(1) \mathbf{A} is true but \mathbf{R} is false.
(2) \mathbf{A} is false but \mathbf{R} is true.
(3) Both \mathbf{A} and \mathbf{R} are true and \mathbf{R} is the correct explanation of \mathbf{A}.
(4) Both \mathbf{A} and \mathbf{R} are true but \mathbf{R} is NOT the correct explanation of \mathbf{A}.
Answer: Option (3)
Explanation:
Glycolysis is a metabolic pathway in which glucose is broken down to form pyruvate with the release of energy.
ATP is consumed in two steps during the preparatory phase of glycolysis.
In the first step, glucose is phosphorylated to glucose-6-phosphate using one molecule of ATP.
In the third step, fructose-6-phosphate is phosphorylated to fructose-1,
6-diphosphate using another molecule of ATP.
Thus, ATP is used at two specific steps in glycolysis, making Assertion A true.
The Reason R correctly describes these two ATP-consuming steps and
therefore correctly explains Assertion A.
Hence, Option (3) is the correct answer.