Arrange the following carbohydrate molecules in the increasing molecular weights:

[a] Starch

[b] Sucrose

[c] Glucose

[d] Amylopectin

Choose the correct answer from the options given below:

Correct option is C

Correct option: (a) — (c), (b), (a), (d)
Explanation (Increasing molecular weight = smallest → largest):
· (c) Glucose
· A monosaccharide.
· Smallest unit of carbohydrates.
· Lowest molecular weight.
· (b) Sucrose
· A disaccharide (glucose + fructose).
· Higher molecular weight than glucose.
· (a) Starch
· A polysaccharide composed of many glucose units.
· Much larger molecular weight than sucrose.
· (d) Amylopectin
· A highly branched polysaccharide.
· Has the largest molecular weight among the given molecules.
➡️ Therefore, the correct increasing order of molecular weight is: Glucose → Sucrose → Starch → Amylopectin
❌ Why other options are incorrect
· Option (b):
· Places glucose after starch, which is incorrect.
· Option (c):
· Puts glucose at the end, though it has the smallest molecular weight.
· Option (d):
· Completely reverses the logical order of molecular size.
�� Key Points to Remember
· Molecular weight increases with:
· Degree of polymerization
· Degree of branching
· Monosaccharide < Disaccharide < Polysaccharide
· Amylopectin is one of the largest naturally occurring carbohydrate molecules.