Question

Select sequence of carbohydrates in decreasing units of hexoses.
(A) Starch
(B) Dextrins
(C) Glucose
(D) Sucrose

• A. (A),(B),(C),(D).
• B. (A),(B),(D),(C).
• C. (B),(A),(D),(C).
• D. (C),(B),(D),(A).

Hint:

Decreasing sequence means arranging from the largest polymer (polysaccharide) down to the monomer:
Polysaccharide (Starch) \(\rightarrow\) Oligosaccharide (Dextrins) \(\rightarrow\) Disaccharide (Sucrose) \(\rightarrow\) Monosaccharide (Glucose).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Carbohydrates are classified by their degree of polymerization (DP), which refers to the number of simple sugar (hexose) monomers linked together in their molecular structure.

Step 2: Detailed Explanation:
Let us determine the number of hexose units for each carbohydrate:
- (A) Starch: A complex polysaccharide composed of thousands of linked D-glucose units (\(\text{DP} > 1000\)).
- (B) Dextrins: Intermediate-length carbohydrates produced by the partial hydrolysis of starch, typically containing dozens to hundreds of glucose units (\(\text{DP} \approx 10\text{--}100\)).
- (D) Sucrose: A disaccharide consisting of exactly 2 hexose units (one glucose and one fructose molecule).
- (C) Glucose: A monosaccharide consisting of exactly 1 hexose unit.
Arranging these in decreasing order of hexose units yields:
Starch (A) \(\rightarrow\) Dextrins (B) \(\rightarrow\) Sucrose (D) \(\rightarrow\) Glucose (C).

Step 3: Final Answer:
The correct decreasing sequence of hexose units is (A), (B), (D), (C).