Question

Why are starch and glycogen more suitable than glucose as storage products?

Answer 1

Hint: The presence of storage products in insoluble form prevents accidental loss of energy through secretions or excretions. For a compound to be considered ideal as a storage product, it also should not change the water potential of the cell.

Complete answer:
When we go through the hint we can answer the question by saying that it is not only suitable for starch and glycogen to be used as storage products, instead, it is essential. Starch and glycogen are branched polysaccharides. They are made up of glucose units. Thus, they occupy less space and are considered less bulky.

Another added advantage is that starch and glycogen can be easily hydrolyzed to glucose whenever required. Further, both the polysaccharides are insoluble in water, unlike glucose which shows high water solubility. Thus, starch is a storage product in plants and glycogen in animals.
- Glycogen is an easily mobilized storage form of glucose. Almost all of the glucose residues in glycogen are linked by glycosidic bonds.
- Glycogen synthesis requires an activated form of glucose.
- Glycogen metabolism is controlled by hormonally stimulated cascades.
- This regulation by hormones allows glycogen metabolism to adjust to the needs of the entire organism.

Note:
- Starch and glycogen show less water solubility when compared to glucose.
- By any means, if glucose is stored inside the cells without polymerization, the internal environment of the cell being hypertonic will cause osmosis of water into the cell. This will ultimately lead to the lysis of the cell as a result of osmotic pressure.