BIOLOGY
Nutrients
• The process of providing or obtaining the food necessary for health and growth is called nutrition.
Nutrition is one of the basic function of life in which intake of food, digestion, absorption, assimilation
and egestion of undigested foods are included.
• Nutrient : Nutrient are the substance by which an organism get energy or it is used for biosynthesis of
its body, For example carbohydrate and fat are the source of energy. Whereas proteins and minerals
are the nutrient used for biosynthesis.
• Carbohydrate : Carbohydrates are organic compounds in which the ratio of Carbon, Hydrogen and
Oxygen is 1 : 2 : 1. Carbohydrate in the form of sugar and starch are major intake in animals and
human.
• 50 to 75% energy is obtained by oxidation of carbohydrate. Carbohydrate containing aldehyde
group is called aldose and with ketone group is called ketose. Carbohydrates are derivatives of
polyhydroxy alcohols.
• Classification of carbohydrate : Carbohydrates are classified into three major group.
• Monosaccharides : These are the simple sugar made up of single polyhydroxy or ketone unit. Most
abundant monosaccharides found in nature is glucose containing six carbon atom. Triose, tetrose,
pentoses, heptoses are the type of monosaccharides.
Glucose is a type of hexose sugar.
The sweetest sugar is fructose.
• Oligosaccharides : When 2 to 10 monosaccharides join together they form oligosaccharides. They
are usually crystalline in nature and sweet in taste. Maltose, sucrose, lactose are disaccharides
made up of two monosaccharides.
• Polysaccharides : These are the compound of sugar which are formed due to joining large number
of mono-saccharide. These are insoluble and tasteless. Some example of polysaccharides are
starch, glycogen, cellulose, chitin etc.
• Function of Carbohydrate :
• Carbohydrate is used as fuel. During the process of respiration, glucose break into CO2 and H2O
with the release of energy. One gram of glucose gives 4.2 kilo calories energy.
• Glucose is the source of immediate energy production in the cell.
• Nucleic acids are polymers of nucleosides and nucleotides containing pentose sugar.
• Lactose of milk is formed from glucose and glactose.
• Glucose is used for the formation of fat and amino acid.
• Carbon skeleton of monosaccharides is used in the formation of fatty acid, chitin, cellulose etc.
• Source of Carbohydrate : Wheat, rice, maize, sweet potato, potato and other plant and animals are
the sources of carbohydrate.
• Protein : Protein word was first used by J. Berzelius. This is a complex organic compound made
up of 20 type of amino acids. Approximately 16% of the human body is made up of protein.
Nitrogen is present in protein in addition to C, H & O.
• Nitrogen is essential for protein synthesis.
• Twenty types of amino acid are necessary for human body; out of which 12 are synthesized by
body itself and remaining 8 are obtained by food are called essential amino acid.
• Types of Proteins : On the basis of chemical composition, it is divided into three types :
1. Simple Protein : It consists of only amino acid. Example- Albumins, Globulins, Histones etc.
2. Conjugated Protein : Having some another chemical compounds in addition to amino acid.
Example Chromo protein, Glyco protein etc.
3. Derived Protein : It is derived from the partial digestion of natural protein or its hydrolysis.
Example- Peptone, Peptide, Proteinase etc.
• Animal protein is called first class protein because it contain all the essential amino acid. Egg
contains all essential amino acids.
Function of Protein
• It takes part in the formation of cells, protoplasm and tissues.
• These are important for physical growth. Physical growth hampers by its deficiency. Lack of
proteins causes Kwashiorkor and Marasmus diseases in children.
• In case of necessity protein provide energy to the body.
• Control the development of genetic characters.
• Helpful in conduction also.
• Kwashiorkor : In this disease hands and legs of children get slimmed and the stomach comes out,
caused by deficiency of protein diet.
• Marasmus : In this disease muscles of children are loosened caused by protein deficiency.
Note :
• Biological catalysts are protein molecule known as enzyme which speed up a chemical reaction
remain unchanged after reaction optimaly function at 37°C. Human nails are made up of protein
keratin.
• Soyabeans is the richest source of protein.
• Keratin is the protein which protects the epithelial cells from damage.
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