Which complex carbohydrate contains only \( \alpha \)-1,4-glycosidic bonds in its structure?

• A. Amylose
• B. Cellulose
• C. Glycogen
• D. Amylopectin

Answer: (A)

Verified step by step guidance

1. Understand the structure of glycosidic bonds: Glycosidic bonds are covalent bonds formed between carbohydrate molecules. Specifically, an α-1,4-glycosidic bond connects the first carbon ( $C_1$ ) of one glucose molecule to the fourth carbon ( $C_4$ ) of another glucose molecule in the α-configuration.
2. Review the structure of Amylose: Amylose is a linear polymer of glucose molecules connected exclusively by α-1,4-glycosidic bonds. This makes it unique among the listed carbohydrates.
3. Compare with other carbohydrates: Cellulose contains β-1,4-glycosidic bonds, not α-1,4-glycosidic bonds. Glycogen and Amylopectin both contain α-1,4-glycosidic bonds but also have α-1,6-glycosidic bonds at branch points, making their structures branched rather than linear.
4. Identify the correct carbohydrate: Based on the structural information, Amylose is the only complex carbohydrate in the list that contains exclusively α-1,4-glycosidic bonds without branching.
5. Conclude the reasoning: Amylose is the correct answer because its structure is linear and composed solely of α-1,4-glycosidic bonds, unlike the other options which either have branching or different types of glycosidic bonds.