Question

Consider the following statements regarding starch:
A. Starch is composed of amylose and amylopectin
B. Amylose is a linear polymer of $\alpha$-D-glucose
C. Amylopectin contains $\alpha$-1,6 glycosidic linkages
D. Starch is completely soluble in cold water
E. Starch is a major energy source in human diet
Choose the correct answer from the options given below:

• A. A, B, C, D, E
• B. A, B, C, D
• C. A, B, C, E
• D. A, B, D, E

Hint:

Amylose = linear, Amylopectin = branched ($\alpha$-1,6).

Answer 1

The Correct Option is C

Concept: Starch is a major carbohydrate found in plants and serves as an important energy source. It consists of two main components: amylose and amylopectin.

Step 1: Evaluating Statement A.
Starch consists of:
• Amylose (linear)
• Amylopectin (branched) Hence, Statement A is correct.

Step 2: Evaluating Statement B.
Amylose:
• Is a linear polymer
• Contains $\alpha$-1,4 glycosidic linkages
• Composed of $\alpha$-D-glucose units Thus, Statement B is correct.

Step 3: Evaluating Statement C.
Amylopectin:
• Contains $\alpha$-1,4 linkages in chains
• Contains $\alpha$-1,6 linkages at branching points Hence, Statement C is correct.

Step 4: Evaluating Statement D.
Starch is:
• Insoluble in cold water
• Forms suspension
• Swells and gelatinizes only upon heating Thus, Statement D is incorrect.

Step 5: Evaluating Statement E.
Starch:
• Is a primary dietary carbohydrate
• Provides major portion of caloric intake Hence, Statement E is correct.

Step 6: Final selection.
Correct statements: \[ A, B, C, E \] Final Conclusion:
Option (3) is correct.