Which process uses water to break large molecules into smaller ones?

• A. Hydrolysis
• B. Dehydration synthesis
• C. Condensation
• D. Photosynthesis

Answer: (A)

Water-splitting reactions break down large molecules into smaller ones. This process, called hydrolysis, uses a water molecule to cleave bonds within a polymer, adding a hydrogen to one fragment and a hydroxyl group to the other. That’s how complex sugars, proteins, and fats are digested into their basic building blocks.

Dehydration synthesis, by contrast, does the opposite: it joins monomers into polymers by removing a water molecule. Condensation is another term for that same idea. Photosynthesis uses light energy to assemble sugars from carbon dioxide and water, building up molecules rather than breaking them apart. So the reaction that uses water to cut large molecules into smaller pieces is hydrolysis.