Question

Which one of the following bonds is formed at the branch point in glycogen?

• A. \(\alpha\)-1, 4 glycosidic bond
• B. \(\alpha\)-1, 6 glycosidic bond
• C. \(\beta\)-1, 4 glycosidic bond
• D. \(\beta\)-1, 6 glycosidic bond

Hint:

Remember: Glycogen contains \(\alpha\)-1,4 linkages in straight chains and \(\alpha\)-1,6 linkages at branch points.

Answer 1

The Correct Option is B

Step 1: Understand the structure of glycogen.
Glycogen is a highly branched polysaccharide that serves as the storage form of glucose in animals. It is composed entirely of glucose units.

Step 2: Identify the main chain linkage.
In glycogen, the linear chains of glucose molecules are connected mainly through
\[ \alpha(1\rightarrow4) \] glycosidic bonds.

Step 3: Understand branch formation.
At certain points, glycogen forms branches to increase solubility and allow rapid release of glucose during metabolism.

Step 4: Identify the bond at branch points.
The branch points are formed when a glucose unit is attached through an
\[ \alpha(1\rightarrow6) \] glycosidic linkage.

Step 5: Analyze option (A).
\(\alpha\)-1,4 glycosidic bonds are present in the straight chains, not at branch points. Hence, option (A) is incorrect.

Step 6: Analyze remaining options.
\(\beta\)-glycosidic bonds are characteristic of structural polysaccharides such as cellulose, not glycogen. Therefore, options (C) and (D) are incorrect.

Step 7: Final conclusion.
Thus, the bond formed at the branch point in glycogen is
\[ \boxed{\alpha\text{-1,6 glycosidic bond}} \]
Hence, the correct answer is option (B).