CARBOHYDRATES
Carbohydrates:-
Carbohydrates are primarily produced by plants and form a very large group of naturally occurring organic compounds. Some common examples are cane sugar, glucose, starch, etc. Most of them have a general formulae, (Cx(H2O)y) and were considered as hydrates of carbon from where the name carbohydrate was derived.
Chemically, the carbohydrate may be defined as "Optically active polyhydroxy aldehyde or ketones or the compound which produce such units on hydrolysis". Some of the carbohydrates, which are sweet in taste, are so called sugars. The most common sugar, used in our homes is named as sucrose whereas the sugar present in milk is known as lactose.
Classification of Carbohydrates:-
(A).Monosaccharides:
A carbohydrate that can't be hydrolysed further to give simpler unit of polyhydroxy aldehyde or ketone is called a monosaccharide. Some cmmon examples are glucose, fructose, ribose, etc.
Monosaccharides are further Classified on the basis of number of carbon atoms and the functional group present in them. If a monosaccharides conatins an aldehyde group, it is known as aldose and if it contains a Ketone group, it is known as keto group.
1. Glucose:
If sucrose is boiled with dilute HCl or H2SO4 in alcholic solution, glucose and fructose are obtained in equal amounts.
2. Fructose:
(B). Disaccharides:-
The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecules. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage.
1. Sucrose:-
One of the common disaccharides is sucrose which on hydrolysis gives equimolar mixture of D-(+)-glucose and D-(-)Fructose.
Hydrolysis of sucrose beings about a change in the sign of rotation, from dextro to laevo and the product is named an invert gas.
2.Lactose:
It is more commonly known as milk sugar since the disaccharide is found in milk. It is composed of α-D-galactose and β-D-glucose. The linkage is between C1 of galactose and C4 of glucose. Hence it is also a reducing sugar.
3.Maltose:
Another disaccharide, maltose is composed of Two α-D-glucose units in which C-1of one Glucose(1) is linked to C-4 of another glucose unit(2).The free aldehyde group can be produced at C1 properties of it is a reducing sugar.
(C). Oligosaccharides:-
An oligosaccharide is a saccharide polymer containing a small number of monosaccharides. Oligosaccharides can have many functions including cell recognition and cell binding.
1.Raffinose:
Raffinose is a trisaccharide composed of galactose, glucose, and fructose. It can be found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains.
2.Stachyose:
Stachyose is a tetrasaccharide consisting of two α-D-galactose units, one α-D-glucose unit, and one β-D-fructose unit sequentially linked as galgalglcfru. Together with related oligosaccharides such as raffinose, Stachyose occurs naturally in numerous vegetables and other plants.
(D). Polysaccharides:-
Carbohydrates which yield large number of monosaccharide units of hydrolysis are called polysaccharides. Some common examples for starch cellulose, glycogen, etc. Polysaccharides are not sweet in taste, hence they are also called non-sugar.
Polysaccharides contain a large number of monosaccharide units joined together by glycosidic linkage . They mainly act as the food storage or structural materials.
1.Cellulose:
Cellulose exclusively in plants and it is the most abundant organic substance in plant kingdom. It is predominant constituent of cell wall of plant cells. Cellulose is a straight chain polysaccharide composed only of β-D-glucose units which are joined by glycosidic linkage between C1 of one Glucose unit and C4 of the next glucose unit.
2. Starch:
Starch is the main storage polysaccharide of plants. It is the most important resource for human beings. High content of starch is found in cereals, roots, and some vegetables. It is a polymer of α-glucose and consists of two components:-
(a) Amylose- Amylose is water soluble component which constitutes about 15-20% of starch.
(b) Amylopectin- Amylopectin is water soluble component which constitutes about 80-85% of starch.
3. Glycogen:
The carbohydrates are stored in animal body as glycogen. It is also known as animal starch because its structure is similar to amylopectin and is rather more highly branched. It is the present in liver, muscles and brain. when the body needs glucose, enzymes break the glycogen down to glucose. Glucogen is also found in yeast and fungi.
Carbohydrates:-
Carbohydrates are primarily produced by plants and form a very large group of naturally occurring organic compounds. Some common examples are cane sugar, glucose, starch, etc. Most of them have a general formulae, (Cx(H2O)y) and were considered as hydrates of carbon from where the name carbohydrate was derived.
Chemically, the carbohydrate may be defined as "Optically active polyhydroxy aldehyde or ketones or the compound which produce such units on hydrolysis". Some of the carbohydrates, which are sweet in taste, are so called sugars. The most common sugar, used in our homes is named as sucrose whereas the sugar present in milk is known as lactose.
Classification of Carbohydrates:-
(A).Monosaccharides:
A carbohydrate that can't be hydrolysed further to give simpler unit of polyhydroxy aldehyde or ketone is called a monosaccharide. Some cmmon examples are glucose, fructose, ribose, etc.
Monosaccharides are further Classified on the basis of number of carbon atoms and the functional group present in them. If a monosaccharides conatins an aldehyde group, it is known as aldose and if it contains a Ketone group, it is known as keto group.
1. Glucose:
If sucrose is boiled with dilute HCl or H2SO4 in alcholic solution, glucose and fructose are obtained in equal amounts.
2. Fructose:
Fructose, or fruit sugar, is a simple ketonic monosaccharide found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into blood during digestion.
It nature is Polyhydroxy ketome. Melting poit 102°C.(B). Disaccharides:-
The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecules. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage.
1. Sucrose:-
One of the common disaccharides is sucrose which on hydrolysis gives equimolar mixture of D-(+)-glucose and D-(-)Fructose.
Hydrolysis of sucrose beings about a change in the sign of rotation, from dextro to laevo and the product is named an invert gas.
2.Lactose:
It is more commonly known as milk sugar since the disaccharide is found in milk. It is composed of α-D-galactose and β-D-glucose. The linkage is between C1 of galactose and C4 of glucose. Hence it is also a reducing sugar.
3.Maltose:
Another disaccharide, maltose is composed of Two α-D-glucose units in which C-1of one Glucose(1) is linked to C-4 of another glucose unit(2).The free aldehyde group can be produced at C1 properties of it is a reducing sugar.
(C). Oligosaccharides:-
An oligosaccharide is a saccharide polymer containing a small number of monosaccharides. Oligosaccharides can have many functions including cell recognition and cell binding.
1.Raffinose:
Raffinose is a trisaccharide composed of galactose, glucose, and fructose. It can be found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains.
2.Stachyose:
Stachyose is a tetrasaccharide consisting of two α-D-galactose units, one α-D-glucose unit, and one β-D-fructose unit sequentially linked as galgalglcfru. Together with related oligosaccharides such as raffinose, Stachyose occurs naturally in numerous vegetables and other plants.
(D). Polysaccharides:-
Carbohydrates which yield large number of monosaccharide units of hydrolysis are called polysaccharides. Some common examples for starch cellulose, glycogen, etc. Polysaccharides are not sweet in taste, hence they are also called non-sugar.
Polysaccharides contain a large number of monosaccharide units joined together by glycosidic linkage . They mainly act as the food storage or structural materials.
1.Cellulose:
Cellulose exclusively in plants and it is the most abundant organic substance in plant kingdom. It is predominant constituent of cell wall of plant cells. Cellulose is a straight chain polysaccharide composed only of β-D-glucose units which are joined by glycosidic linkage between C1 of one Glucose unit and C4 of the next glucose unit.
2. Starch:
Starch is the main storage polysaccharide of plants. It is the most important resource for human beings. High content of starch is found in cereals, roots, and some vegetables. It is a polymer of α-glucose and consists of two components:-
(a) Amylose- Amylose is water soluble component which constitutes about 15-20% of starch.
(b) Amylopectin- Amylopectin is water soluble component which constitutes about 80-85% of starch.
3. Glycogen:
The carbohydrates are stored in animal body as glycogen. It is also known as animal starch because its structure is similar to amylopectin and is rather more highly branched. It is the present in liver, muscles and brain. when the body needs glucose, enzymes break the glycogen down to glucose. Glucogen is also found in yeast and fungi.
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