Difficulty: Easy
Correct Answer: Amylose
Explanation:
Introduction / Context:
Disaccharides are sugars composed of two monosaccharide units (e.g., glucose + glucose for maltose; glucose + galactose for lactose). In contrast, polysaccharides consist of many monosaccharides linked together and serve structural or storage roles. This item asks you to identify the entry that is not a disaccharide.
Given Data / Assumptions:
Concept / Approach:
Classify each sugar by its degree of polymerization. Amylose contains long chains of α-1→4-linked glucose units (n ≫ 2), making it a polysaccharide, not a disaccharide. The others listed are classical disaccharides used in laboratory and nutritional contexts.
Step-by-Step Solution:
Verification / Alternative check:
Chemical assays and enzymatic digestion patterns (e.g., amylase on starch) corroborate amylose’s polymeric nature beyond two units.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing amylose with “amylose unit” or with maltose due to similar names; they differ fundamentally in size and structure.
Final Answer:
Amylose
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