The hydrolysis of sucrose to glucose and fructose in the preparatory steps of glycolysis is catalysed by which enzyme?

The correct option is Invertase.

Explanation

Sucrose is a disaccharide consisting of glucose and fructose. In plants, carbohydrates are often transported as sucrose. Before these sugars can enter the glycolytic pathway for energy production, sucrose must be hydrolyzed into its constituent monosaccharides.

Analysis of Options

• Invertase Invertase: Correct. Invertase (also known as sucrase) catalyzes the hydrolysis of sucrose into glucose and fructose. These two monosaccharides then readily enter the glycolytic pathway.
• Hexokinase Hexokinase: Incorrect. Hexokinase is responsible for the phosphorylation of glucose (or fructose) to form glucose-6-phosphate (or fructose-6-phosphate). This step occurs after the hydrolysis of sucrose.
• Isomerase Isomerase: Incorrect. Isomerases catalyze the structural rearrangement of isomers. For instance, phosphoglucoisomerase converts glucose-6-phosphate into fructose-6-phosphate during glycolysis, but it does not break down sucrose.
• Phosphatase Phosphatase: Incorrect. Phosphatases are enzymes that remove phosphate groups from substrates. They are not involved in the cleavage of the glycosidic bond in sucrose.

Key Takeaway: Invertase is the enzyme responsible for converting sucrose into glucose and fructose, providing the necessary monosaccharides for the glycolytic pathway.