Biology – Carbohydrates and lipids | e-Consult
Carbohydrates and lipids (1 questions)
Both starch and cellulose are polysaccharides made from monosaccharide units, but they differ significantly in their structure and function.
Starch is a polysaccharide composed of glucose units linked by α(1→4) glycosidic bonds in the linear chains. It also contains α(1→6) glycosidic bonds that create branches. Starch serves as the primary energy storage molecule in plants. It exists in two forms: amylose (linear) and amylopectin (branched). Amylose is more readily digested than amylopectin.
Cellulose, as described previously, is a polysaccharide composed of glucose units linked by β(1→4) glycosidic bonds. It is the main structural component of plant cell walls. Cellulose provides rigidity and support to the plant. It is not a significant energy storage molecule.
Here's a table summarizing the key differences:
| Feature | Starch | Cellulose |
| Monosaccharide Unit | Glucose | Glucose |
| Glycosidic Bonds | α(1→4) with α(1→6) branches | β(1→4) |
| Primary Function | Energy storage | Structural support |
| Digestibility | Easily digestible | Indigestible by most organisms |