By what process is starch converted into maltose?

Step 1: Analyze the question The question asks which process breaks starch down into maltose. Starch is a large polysaccharide, and maltose is a disaccharide (two glucose units joined together). So a large molecule is being broken into a smaller one.

Step 2: Explain the concept

• Hydrolysis is the breakdown of a compound by adding water. Enzymes catalyse it in digestion.
• Condensation is the opposite. Small molecules join together and water is removed.
• Translocation is the transport of manufactured food (such as sucrose) through the phloem of plants.
• Photosynthesis is the process by which green plants make glucose from carbon dioxide and water using light.

Step 3: Solution Starch is broken down by the enzyme amylase (found in saliva as salivary amylase, and in pancreatic juice). Amylase adds water across the glycosidic bonds of starch, splitting it into maltose:

Starch + water → (amylase) → maltose

Adding water to break a bond is hydrolysis. Maltose is then hydrolysed by maltase into glucose:

Maltose + water → (maltase) → 2 glucose

Step 4: Check the options

• A. Hydrolysis: correct, because water is used to break the bonds.
• B. Condensation: wrong, because it builds larger molecules (for example, maltose from glucose).
• C. Translocation: wrong, because it is the movement of substances in plants, not a chemical breakdown.
• D. Photosynthesis: wrong, because it makes food rather than digesting it.

Answer: A. Hydrolysis

Exam tip: "Hydro" means water and "lysis" means splitting, so hydrolysis is splitting with water. In digestion, large molecules are always broken down by hydrolysis. Remember that condensation builds up and hydrolysis breaks down.