It is the process by which living organism aquire energy or take in material for metabolism.

Why do we eat ?

• We eat to maintain, repair old and warm out cells.
• We eat in other to grow and for the development of the body tissues and organs.
• It provide energy for various metabolic activities.

HOLOZIOC NUTRITION

            This is a type of nutrition that involve the taking in of large complex substances which are digested into or broken down into simple soluble and absorbable substances. This is common in animals.

BIOCHEMISTRY OF FOOD SUBSTANCES

There are principal seven main classes of food which can be differenciated into primary food class and welfare food classes which include;

• Carbohydrate
• Proteins
• Lipids(fat and oil)
• Vitamins
• Mineral salts
• Roughage
• Water

N.B: Primary classes help in the maintainance of life welfare class is important for the well being of the individual and the absence of welfare classes will lead to a deficiency disease.

1. CARBONDIOXIDE

They are organic compound manufactured by plant from the inorganic compound CO₂  and H₂O Cabohydrate is a natural polymer having the element carbon, hydrogen and oxygen. Hydrogen and oxygen are in the ratio of 2:1 and they have a general formular (CH₂O)n where n signifies the total number of carbohydrate to another.

Carbohydrate is the commonest class of food e.g if CH₂O₆

Cabohydrate can be classify into 3 group.

Monosaccharides e.g simple sugar

Dissaccharides e.g maltose,lactose,sucrose

Polysaccharides e.g cellulose, chitin starch, glycogen.

• MONOSSACHARIDES

They are simple sugar with a general formular of  C_x(H₂O)_y

 Monossachides are the basic structural units of carbohydrate they are recluling sugar

• DISSACCHARIDES

A dissacharide has the general formular of C_n(H₂O)2_n-1. Where N is greater or less than 12 they also sweat and soluble in water. A dissacchides is form by the formation of the bond 1,4 glycordic bond.

A dissacharides can be broken to monosaccharides bythe process of hydrolysis.

• POLYSACCHARIDES

They include glycogen, starch, cellulose and they are formed by the combination of many monosacchides. They are sweet and they do not form crystals, they are only slitly soluble in water, all polysaccharide have a general formular

Properties of carbohydrate

• They are sweet and soluble while non-sugar  are not sweet
• The sugar can be crystalise while the non-sugars cannot by crystalise.
• The non sugars can easily be hydrolise to sugar.
• Sugar are colourless why non-sugar are colour.

Importance of carbohydrate

• They form compound of cell wall of plants and exoskeleton  of insects and cellulose chitin respectively.
• They may be concentrated involves in valvoles of plant hence increasing osmatic concentration of valuole. The high concentration lead to increase rate at which cell in plants take in water by osmotis e.g glucose
• They provide source of respiratory energy in cell during tissues respiration. This comes from glucose each gram of glucose yield 16kg where broken down completely by respiration.
• They serves as food reserve, such as sugar and starch in plant and glycogen in animals.
• They form important constituent of nucleic acid and ATP e.g the pentose sugar of DNA and RNA

2. PROTEINS:

The living material(protoplasm) in a cell is made up of protein forms the bulk of plant and animals tissues. In plants, as well as in animals protein can be formed like carbohydrate by the addition of altrogen, sulphur and phosphorus. Plant food consumed by animals contain a certain amount of ptotein which is lowering concentration than those present in animals for this reason plant protein is known as second class protein since the proportion is not as high as in animals protein. In animals, protein becomes highly concertrated in certain organs such as the muscle which therefore selves as the main source of protein. Animal protein takingin as food we fish, meat, egg, beans and are known as Fish class protein.This is because it contain all the essential amino acid. A lot of protein in our diet cause serious deficiency problems that result in diseases such as kwashiorkor, maras mus

Composition of Protein

Protein are food substances containing the element carbon, oxygen, hydrogen, nitrogen and some time sulphure and phosphure. The fundamental unit or building black in protein is Amino acid with

Properties of protein

• They have both basic and acidic properties(the are amphoteric)
• They are denatured(they are easily destroy) above temperature of 40°
• They dissolve with difficulties in water.
• Unfavorable P.H denature or destroy protein.
• They are coagulated by boiling.

IMPORTANCE OF PROTEIN

• They form enzymes anti-bodies and hormones  e.g hoypsin and insulin etc.
• Needed in building protoplasm and also to repair warm out tissues.
• Used in treatment of kwashiorkor in children
• Stored as food reserves
• Use to manufacture nucleic acid( DNA and RNA)
• Use for lubrication e.g mucire saliva and mucus