1 CARBOHYDRATES
1.1 Introduction
Referred to as a saccharides (greek: sakcharon means sugar).
Also known as hydrates of carbon because in most of the carbohydrates H and O are present
in the same ratio as in water.
Carbohydrates - most abundant biomolecules in the nature.
Primary components = carbon, hydrogen, and oxygen.
Simple sugars called monosaccharides are the building blocks of carbohydrates
A monosaccharide can be a polyhydroxy aldehyde (aldose) or a polyhydroxy ketone (ketose).
1.2 Functions
Act as precursor for many organic compounds. For example they are intermediates in the
biosynthesis of fats, proteins and nucleotides (RNA and DNA).They get associated with lipids
and proteins to form surface antigens, receptor molecules, vitamins, and antibiotics.
Structural component of many organisms. They form structural and protective components,
like in the cell wall of plants and microorganisms. Structural elements in the cell walls of
bacteria (peptidoglycan or murein), plants (cellulose), and animals (chitin).
It also involves in immediate source of energy demands of the body by serving as the storage
form of energy (glycogen). Living organisms use carbohydrates as accessible energy to fuel
cellular reactions. They are the most abundant dietary source of energy (4kcal/gram) for all
living beings.
Serve as energy stores, fuels, and metabolic intermediates. It is stored as glycogen in animals
and starch in plants.
Markers of cellular identity (oligosaccharides on the surface of cells of multicellular
organisms)
They also involved in the structural and cellular functions of cell such as- fertilization, cell
growth and adhesion.
They Carbohydrates aid in the regulation of nerve tissue and is the energy source for the brain.
They are linked to many proteins and lipids. Such linked carbohydrates are important in cell-
cell communication and in interactions between cells and other elements in the cellular
environment.
In animals, they are an important constituent of connective tissues.
Carbohydrates that are rich in fiber content help to prevent constipation.
Also, they help in the modulation of the immune system.
1
,1.3 Classification
Carbohydrates are classified into three major groups depending upon number of simple
sugars
I. Monosaccharides
II. Oligosaccharides
III. Polysaccharides
1.3.1 Monosaccharides
The simplest group of carbohydrates
Termed simple sugars since they cannot be further hydrolyzed.
Empirical structure for carbohydrates is (CH2O)n., where n is between 3 and 8. Not all sugars
have this formula, however. Deoxyribose, the sugar found in every nucleotide in a DNA
molecule lacks one oxygen and thus has the formula C5H10O4.
Colorless, crystalline solids that are soluble in water and insoluble in a non-polar solvent.
They are classified according to the number of carbon atoms they contain and also on the basis
of the functional group present.
2
, The monosaccharides thus with 3, 4, 5, 6, 7 … carbons are called trioses, tetroses, pentoses,
hexoses, heptoses, etc., and also as aldoses or ketoses depending upon whether they contain
aldehyde or ketone group. (monosaccharides with ketone groups)
They possesses a free aldehyde or ketone group.
If the sugar has an aldehyde group, meaning that the carbonyl C is the last one in the
chain, it is known as an aldose. (monosaccharides with aldehyde groups)
If the carbonyl C is internal to the chain, so that there are other carbons on both sides of it,
it forms a ketone group and the sugar is called a ketose.
D-glucose is the most abundant monosaccharides on the earth.
3
, 4
1.1 Introduction
Referred to as a saccharides (greek: sakcharon means sugar).
Also known as hydrates of carbon because in most of the carbohydrates H and O are present
in the same ratio as in water.
Carbohydrates - most abundant biomolecules in the nature.
Primary components = carbon, hydrogen, and oxygen.
Simple sugars called monosaccharides are the building blocks of carbohydrates
A monosaccharide can be a polyhydroxy aldehyde (aldose) or a polyhydroxy ketone (ketose).
1.2 Functions
Act as precursor for many organic compounds. For example they are intermediates in the
biosynthesis of fats, proteins and nucleotides (RNA and DNA).They get associated with lipids
and proteins to form surface antigens, receptor molecules, vitamins, and antibiotics.
Structural component of many organisms. They form structural and protective components,
like in the cell wall of plants and microorganisms. Structural elements in the cell walls of
bacteria (peptidoglycan or murein), plants (cellulose), and animals (chitin).
It also involves in immediate source of energy demands of the body by serving as the storage
form of energy (glycogen). Living organisms use carbohydrates as accessible energy to fuel
cellular reactions. They are the most abundant dietary source of energy (4kcal/gram) for all
living beings.
Serve as energy stores, fuels, and metabolic intermediates. It is stored as glycogen in animals
and starch in plants.
Markers of cellular identity (oligosaccharides on the surface of cells of multicellular
organisms)
They also involved in the structural and cellular functions of cell such as- fertilization, cell
growth and adhesion.
They Carbohydrates aid in the regulation of nerve tissue and is the energy source for the brain.
They are linked to many proteins and lipids. Such linked carbohydrates are important in cell-
cell communication and in interactions between cells and other elements in the cellular
environment.
In animals, they are an important constituent of connective tissues.
Carbohydrates that are rich in fiber content help to prevent constipation.
Also, they help in the modulation of the immune system.
1
,1.3 Classification
Carbohydrates are classified into three major groups depending upon number of simple
sugars
I. Monosaccharides
II. Oligosaccharides
III. Polysaccharides
1.3.1 Monosaccharides
The simplest group of carbohydrates
Termed simple sugars since they cannot be further hydrolyzed.
Empirical structure for carbohydrates is (CH2O)n., where n is between 3 and 8. Not all sugars
have this formula, however. Deoxyribose, the sugar found in every nucleotide in a DNA
molecule lacks one oxygen and thus has the formula C5H10O4.
Colorless, crystalline solids that are soluble in water and insoluble in a non-polar solvent.
They are classified according to the number of carbon atoms they contain and also on the basis
of the functional group present.
2
, The monosaccharides thus with 3, 4, 5, 6, 7 … carbons are called trioses, tetroses, pentoses,
hexoses, heptoses, etc., and also as aldoses or ketoses depending upon whether they contain
aldehyde or ketone group. (monosaccharides with ketone groups)
They possesses a free aldehyde or ketone group.
If the sugar has an aldehyde group, meaning that the carbonyl C is the last one in the
chain, it is known as an aldose. (monosaccharides with aldehyde groups)
If the carbonyl C is internal to the chain, so that there are other carbons on both sides of it,
it forms a ketone group and the sugar is called a ketose.
D-glucose is the most abundant monosaccharides on the earth.
3
, 4
