Glucose
Glucose is a simple sugar with the molecular formula C6H12O6. Glucose is the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight, where it is used to make cellulose in cell walls, the most abundant carbohydrate in the world.
Though glucose is called a simple sugar, its chemistry is really complex. Glucose, which is oftentimes referred to as dextrose, is made up of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. When combined, it can take the form of a variety of arrangements; thus isomers are born. Among the first two isomers that chemists discovered were the alpha glucose and the beta glucose.
Alpha and beta glucose are the isomers of D-glucose. The D-glucose can exist in two forms alpha-D-glucose and beta-D-glucose. When alpha-glucose molecules are joined chemically to form a polymer starch is formed. When beta-glucose molecules are joined to form a polymer cellulose is formed.
Both alpha and beta glucose have the same molecular formula but only differ in the direction of their -OH (hydroxyl) and -H (hydrogen) groups on carbon 1. Alpha glucose has the -OH attached below the ring, while beta glucose has its -OH group above the ring.
These two forms of glucose are (stereo)isomers, because they contain the same atoms, but they differ in the arrangement of their atoms in space.
They can also be called epimers because they represent different configurations of atoms about a single stereogenic centre – in this case carbon 1. They can also be called anomers because they differ only in configuration at the hemiacetal carbon 1, also called the anomeric carbon. This difference is not enough to warrant giving these two forms different names, apart from α-D-glucopyranose and β-D-glucopyranose of course!
This orientation is the reason for the difference between the disaccharides maltose and cellobiose. In maltose there is a (1-4) glycosidic bond formed between one α-glucose and another; in cellobiose a (1-4) glycosidic bond is formed between one β-glucose and another, and this has important consequences for the types of molecules which can be formed as a result of further condensation reactions.
Alpha, 1-4 linkages make starch (amylose and amylopectin) fairly easily broken down by enzymes whereas beta, 1-4 linkages result in linear microfibrils of cellulose which are difficult to break down.
What Is Alpha Glucose?
Alpha glucose is an isomer of D-glucose in which the -OH group present on the first carbon atom is on the same side of the CH2OH group. As per the chair conformation, alpha glucose has a cyclic structure with four -OH groups attached to the carbon chain.
The structural cycle is formed by an oxygen bridge which means that the two carbon atoms of the terminals of the carbon chain are joined through an oxygen bond. The ring structure of alpha glucose is a three-dimensional structure and to avoid confusion, it is known as glucopyranose.
The alpha glucose is comparatively less stable. The melting point of alpha glucose is 146 degree Celsius and a specific rotation of it is 112.2 degrees. Alpha glucose can be easily transformed into beta glucose.
The glycosidic bond of two glucose molecules results in the formation of a disaccharide called Maltase. The polymer of alpha glucose is known as starch which can be easily broken down by enzymes.
What You Need To Know About Alpha Glucose
- Alpha glucose is an isomer of glucose that has – OH bunch present on the primary carbon iota is on the very side as that of the CH2OH particle bunch.
- Alpha glucose has the property to take shape as alpha-glycopyranose in its watery arrangement.
- Alpha glucose has a compact structure but its molecules can be separated from it, therefore, it is comparatively less stable. The melting point of alpha glucose is 146 degree Celsius.
- The glycosidic or 1-4 connection between two alpha glucose particles brings about the arrangement of disaccharides which is named as Maltase. Alpha glucose can be handily changed over to beta glucose.
- The explicit pivot of alpha D-glucose is 112.2 degrees. Starch is a polymer of alpha glucose which can be separated effectively by chemicals.
What Is Beta Glucose?
Beta glucose is an isomer of D-glucose in which the -OH group present on the first carbon atom is on the opposite side of the CH2OH group. It has the -OH group attached to the main carbon chain. The cyclic structure of beta glucose is the same as that of alpha glucose.
Beta glucose is more stable. The melting point of beta glucose is 150 degree Celsius and a specific rotation of it is 18.7 degrees. Beta glucose can also be easily transformed into alpha glucose.
The glycosidic bond of two beta glucose molecules results in the formation of cellobiose. The polymer of beta glucose is known as cellulose which cannot be easily broken down by enzymes.
What You Need To Know About Beta Glucose
- Beta glucose is additionally an isomer of D-glucose in which the – OH bunch put on the principal carbon particle is put on the contrary side of the CH2OH bunch.
- Beta glucose can crystalize either as beta glycopyranose or as beta glycopyranose hydrate from its watery arrangement.
- Beta glucose is more stable and therefore molecules cannot be taken it easily. The melting point of beta glucose is 150 degree Celsius.
- The glycosidic connection between two beta glucose prompts the development of cellobiose. Beta glucose is effectively convertible into alpha glucose.
- The beta glucose has a particular pivot of 18.7 degrees. Cellulose is a polymer of beta glucose and cannot be separated by proteins.
Difference Between Alpha And Beta Glucose In Tabular Form
| BASIS OF COMPARISON | ALPHA GLUCOSE | BETA GLUCOSE |
| Description | Alpha glucose is an isomer of glucose that has – OH bunch present on the primary carbon iota is on the very side as that of the CH2OH particle bunch. | Beta glucose is additionally an isomer of D-glucose in which the – OH bunch put on the principal carbon particle is put on the contrary side of the CH2OH bunch. |
| Polymer | Starch is a polymer of alpha glucose which can be separated effectively by chemicals. | Cellulose is a polymer of beta glucose and cannot be separated by proteins. |
| Crystallization Property | Alpha glucose has the property to take shape as alpha-glycopyranose in its watery arrangement. | Beta glucose can crystalize either as beta glycopyranose or as beta glycopyranose hydrate from its watery arrangement. |
| Stability | Alpha glucose has a compact structure but its molecules can be separated from it, therefore, it is comparatively less stable. | Beta glucose is more stable and therefore molecules cannot be taken it easily. |
| Meting Point | The melting point of Alpha glucose is 146 degree Celsius. | The melting point of beta glucose is 150 degree Celsius. |
| Inter Conversation | Alpha glucose can be handily changed over to beta glucose. | Beta glucose is effectively convertible into alpha glucose. |
| Explicit Pivot | The explicit pivot of alpha D-glucose is 112.2 degrees. | The beta glucose has a particular pivot of 18.7 degrees. |
| Solidification | Alpha glucose solidifies into alpha glycopyranose in the fluid arrangement. | Beta glucose solidifies either into beta glycopyranose or beta glycopyranose hydrate in the watery arrangement. |
| Function | Alpha glucose is the primary energy source in the body | Beta glucose is used as a structural substance. |
Similarities Between Alpha And Beta Glucose
1. Classification
Both alpha and beta glucose are classified as sugars as they have the same components. They are also considered isomers, as they have the same number and type of atoms, but they have different atom formations.
2. Molecular Formula
Beta and alpha glucose have the same molecular formula (C6H12O6). The difference lies in the arrangement of the atoms in space.
3. Stereogenic Center
Alpha and beta glucose have the same stereogenic center – carbon 1. Both types of glucose attach the -OH to carbon 1 – only in different positions.
4. Source
They have the same general source, food, primarily plants. They are both ingested and enter the body through the mouth.