Which of the following sugars is a product of the condensation of monosaccharides?

Analyze the question: It asks which sugar is formed when monosaccharides (simple sugars) join together by condensation. That means we are looking for a disaccharide, not a monosaccharide.

Explain the concept:

• Monosaccharides are single sugar units that cannot be hydrolysed into simpler sugars. Examples are glucose, fructose and galactose (all C₆H₁₂O₆).
• Disaccharides are formed when two monosaccharides join by a condensation reaction. A molecule of water is lost and a glycosidic bond forms between them.
• Common disaccharides: • Maltose = glucose + glucose • Sucrose = glucose + fructose • Lactose = glucose + galactose

Solution:

Condensation of two glucose units:

C₆H₁₂O₆ + C₆H₁₂O₆ → C₁₂H₂₂O₁₁ + H₂O (glucose + glucose → maltose + water)

Check each option:

• A. Galactose is a monosaccharide, so it is not a product of condensation.
• B. Maltose is a disaccharide formed from two glucose units, so it is a product of condensation.
• C. Glucose is a monosaccharide.
• D. Fructose is a monosaccharide.

Answer: B. maltose.

Exam tip: Sugar names ending in -ose can be monosaccharides or disaccharides, so memorize the three disaccharides: MaSLo, meaning Maltose, Sucrose, Loctose (lactose). Each contains glucose. Anything else in the list is usually a monosaccharide.