Question

Match the carbohydrates in Column I with the correct glycosidic linkages involved in Column II.

Column I	Column II
P. Amylose	1. \(\beta(1\rightarrow4)\)
Q. Sucrose	2. \(\alpha(1\rightarrow4)\)
R. Amylopectin	3. \(\alpha1\rightarrow\beta2\)
S. Cellulose	4. \(\alpha(1\rightarrow4), \alpha(1\rightarrow6)\)

• A. P-4; Q-3; R-2; S-1
• B. P-2; Q-1; R-4; S-3
• C. P-2; Q-3; R-4; S-1
• D. P-1; Q-3; R-4; S-2

Hint:

Amylose and cellulose are unbranched (differ only in alpha vs beta 1,4 links), amylopectin adds alpha 1,6 branches, and sucrose's link is alpha1 to beta2 between glucose and fructose.

Answer 1

The Correct Option is C

This is a pure recall question about the exact glycosidic bond in four common carbohydrates. The fastest route is to fix each carbohydrate's bond first, then check which option lines up.

1. Option (A) P-4; Q-3; R-2; S-1: This gives amylose the mixed $\alpha(1\rightarrow4)/\alpha(1\rightarrow6)$ linkage (item 4), but amylose is the unbranched starch fraction with only $\alpha(1\rightarrow4)$ bonds; that mixed linkage belongs to amylopectin. This option is wrong.
2. Option (B) P-2; Q-1; R-4; S-3: P (amylose) to item 2, $\alpha(1\rightarrow4)$, is correct, and R (amylopectin) to item 4 is correct. But Q (sucrose) is given item 1, $\beta(1\rightarrow4)$, which is the cellulose bond, and S (cellulose) is given item 3, the sucrose bond. Q and S are swapped, so this option fails.
3. Option (C) P-2; Q-3; R-4; S-1: P-2 fits amylose ($\alpha(1\rightarrow4)$), Q-3 fits sucrose ($\alpha1\rightarrow\beta2$, joining glucose C1 to fructose C2), R-4 fits amylopectin (branched, both $\alpha(1\rightarrow4)$ and $\alpha(1\rightarrow6)$), and S-1 fits cellulose ($\beta(1\rightarrow4)$). Every pair checks out.
4. Option (D) P-1; Q-3; R-4; S-2: Q-3 and R-4 are right, but P (amylose) is given item 1, the $\beta(1\rightarrow4)$ bond of cellulose, while S (cellulose) is given item 2, the $\alpha(1\rightarrow4)$ bond of amylose. P and S are swapped, so this option fails.

Only option (C) assigns every carbohydrate its real bond, so it is the correct match.

Let's summarize:

• Amylose: $\alpha(1\rightarrow4)$ only (unbranched starch).
• Amylopectin: $\alpha(1\rightarrow4)$ chain plus $\alpha(1\rightarrow6)$ branch points (branched starch).
• Cellulose: $\beta(1\rightarrow4)$ (gives it rigid fibers, unlike starch).
• Sucrose: $\alpha1\rightarrow\beta2$ between glucose and fructose (a non-reducing disaccharide).

The correct match is P-2; Q-3; R-4; S-1, option (C).