What is the major structural difference between starch and glycogen?

• A. Starch is composed of $\mathrm{glucose}$ and $\mathrm{fructose}$, while glycogen is composed of $\mathrm{glucose}$ only.
• B. Starch contains only $\alpha -1,6-glycosidic$ bonds, while glycogen contains only $\alpha -1,4-glycosidic$ bonds.
• C. Starch is a linear polymer, while glycogen is highly branched.
• D. Starch is found in animals, while glycogen is found in plants.

Answer: (C)

Verified step by step guidance

1. Identify the primary components of starch and glycogen. Both starch and glycogen are polysaccharides composed of glucose units.
2. Understand the structural configuration of starch. Starch consists of two types of molecules: amylose, which is mostly linear with alpha-1,4-glycosidic bonds, and amylopectin, which is branched with both alpha-1,4 and alpha-1,6-glycosidic bonds.
3. Examine the structure of glycogen. Glycogen is similar to amylopectin but is more highly branched, with frequent alpha-1,6-glycosidic bonds occurring approximately every 8-12 glucose units.
4. Compare the branching patterns. The major structural difference is that starch has a less frequent branching pattern compared to glycogen, making glycogen more compact and highly branched.
5. Clarify the biological context. Starch is primarily found in plants as an energy storage molecule, while glycogen serves a similar purpose in animals, particularly in liver and muscle cells.