Question

What type of glycosidic linkages are present in amylose?

• A. $\alpha$-1,4
• B. $\alpha$-1,6
• C. $\alpha$-1,4 and $\alpha$-1,6
• D. $\beta$-1,4 and $\alpha$-1,6

Hint:

To remember carbohydrate structures:
- Cellulose: Linear, entirely $\beta$-1,4.
- Amylose: Linear, entirely $\alpha$-1,4.
- Amylopectin Glycogen: Branched, featuring both $\alpha$-1,4 (for the straight chains) and $\alpha$-1,6 (for the branch points).

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the specific type of chemical bond (glycosidic linkage) that connects the individual sugar monomers within the macromolecule amylose.

Step 2: Detailed Explanation:
Starch, a major energy storage polysaccharide in plants, is chemically composed of two distinct polymeric components: amylose and amylopectin.
1. Amylopectin: This is the highly branched, water-insoluble component of starch. It consists of long chains formed by $\alpha$-1,4-glycosidic linkages, but it also features frequent branching points that are connected exclusively by $\alpha$-1,6-glycosidic linkages.
2. Amylose: This is the linear (unbranched), water-soluble component of starch. It is structurally a straight, continuous chain composed of thousands of identical $\alpha$-D-glucose units.
Because the chain is perfectly linear without any branching, the glucose monomers are exclusively connected end-to-end between Carbon-1 of one unit and Carbon-4 of the next.
Therefore, amylose contains only $\alpha$-1,4-glycosidic linkages.

Step 3: Final Answer:
The only linkages present in amylose are $\alpha$-1,4, matching option (a).