In plants, sucrose is broken down by the enzyme invertase to yield two monosaccharides that enter the glycolytic pathway. When one molecule of sucrose is respired, what is the total number of ATP molecules utilized in the phosphorylation steps of glycolysis before the cleavage of the 6-carbon sugars occurs?

Step-by-step solution

According to NCERT, sucrose is converted into glucose and fructose by the enzyme invertase, and both these monosaccharides readily enter the glycolytic pathway. Each hexose molecule (glucose or fructose) requires the utilization of two ATP molecules during the preparatory (phosphorylation) phase of glycolysis: 1. First ATP is utilized when the sugar is phosphorylated by hexokinase. 2. Second ATP is utilized in the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate. Since one molecule of sucrose yields