Glycogen and Starch are two polymers of glucose that are found in the living cells. Glucose is produced by the process of photosynthesis in plants and is the simplest form of sugar. Glucose forms polymers to further produce complex sugars or carbohydrates glycogen and starch. During the formation of these polymers, the monomer unit of glucose is held together by glycosidic bonds.
Glycogen vs Starch
The main difference between glycogen and starch is that glycogen is the polymer of glucose that is the main energy component for fungi and animals whereas glucose is the polymer of glucose that is an important energy component for plants.
Glycogen is the essential storage component and the energy producer for animals and fungi. The monomer unit during the formation of glycogen is alpha glucose. It is found in the form of small granules in the cytosol of the cell. In humans, glycogen is stored in the liver cells and the muscle cells.
Starch is a vital component of energy production in plants. The glucose produced by the plants is converted to the insoluble storage substances like starch and fats. Starch is found in the amyloplasts and is the main food component in various plants and fruits.
Comparison Table Between Glycogen and Starch (in Tabular Form)
| Parameters of comparison | Glycogen | Starch |
|---|---|---|
| Definition | Glycogen is the polymeric carbohydrate of glucose that is the major component for animals and fungi. | Starch is the complex sugar of glucose that is the major storage carbohydrate for plants. |
| Monomer chains | Glycogen is the polymer where the monomer units form the short branched chains. It comprises of the monomer unit known as alpha glucose held by glycosidic bonds. | Starch is made up of two further polymers- amylose and amylopectin where former forms the linear and coiled chains and latter forms the branched chains. |
| Molecular Formula | C24H42O21 is the molecular formula for glycogen. | (C6H10O5)n is the molecular formula for starch. |
| Occurs in | Glycogen occurs in the form of small granules. | Starch occurs in the form of grains. |
| Function | It serves as the energy storing carbohydrate in animals. | It serves as the energy storing carbohydrate in plants. |
What is Glycogen?
Glycogen is the energy storage carbohydrate that is found only in animals and plants. It is the polymer of the simple sugar called alpha glucose. The glucose monomer units are held by the strong glycosidic bonds to form the polymer glycogen.
It is also known as the animal starch and is found in liver cells, muscle cells, and stomach. It stores glucose to provide the body with the same when it is energy deficient. It is quite similar to amylopectin but is a highly branched structure.
When the body requires energy, glycogen is instantly broken down into glucose to provide the body energy that it requires. This process is known as glycogenolysis. This process is stimulated with the help of hormone glucagon.
Some important facts about glycogen are:
- It is the energy storage carbohydrate, especially for animals and fungi.
- In humans, glycogen is stored as the body fat in the adipose tissues to provide energy when needed.
- Access to blood sugar glucose is also stored as glycogen with the action of the pancreas to prevent diabetes mellitus.
- The storage of glycogen by the muscle cells helps to keep the body ready for strenuous exercises and actions when required.
What is Starch?
Starch is the essential energy storage component in plants. It is the polymer that is of extreme importance to plants in energy storage and production. Some of the plants that contain starch in the ample amounts are potatoes, rice, corn, etc.
Starch is further formed by the combination of two kinds of molecules namely amylose and amylopectin. Amylose has the monomer units attached in the linear and the coiled structure whereas Amylopectin forms the branched chains.
Starch occurs in the granules called amyloplasts in the plant cells. In plants, starch is further converted to form cellulose that helps in energy production, growth, and repair of the cells.
Some important aspects of starch are as follows:
- Starch is the polysaccharide carbohydrate formed by the monomer called alpha glucose.
- It is made up of the 2 molecules amylose and amylopectin.
- Starch is used for various commercial purposes such as for manufacturing paper and textile industry.
Main Differences Between Glycogen and Starch
- Glycogen is the energy storage carbohydrate that is found mainly in animals and fungi whereas Starch is the energy storage carbohydrate that is found predominantly in plants.
- Glycogen is made up of the single-molecule whereas starch is made up of two molecules namely amylose and amylopectin.
- Glycogen forms the branched-chain structure whereas Starch forms linear, coiled, and branch structure.
- Starch is used for commercial purposes such as paper and textile industry whereas glycogen is not used for commercial purposes.
- Glycogen is stored in liver cells and the muscle cells whereas starch are stored in the amyloplasts of the plant cells.
Conclusion
Glycogen and starch are the polymers of the monomer alpha glucose but differ in various ways. Glycogen is the energy-storing carbohydrate that is found mainly in animals and fungi whereas Starch is the energy storage carbohydrate found in plant cells.
Glycogen is made up of the single-molecule whereas starch comprises two molecules amylose and amylopectin. The basic difference between the two terms is that of their occurrence. Glycogen occurs in the adipose tissues as the body fat and the liver cells. It provides energy to the body whenever required.
Starch is stored by plant cells in the amyloplasts and is also used for various commercial purposes such as the textile and paper industry.
References
- https://www.sciencedirect.com/science/article/pii/S1874604708600906