Biochemistry is the study of the chemical processes in living organisms. It deals with the structures and functions of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other bio-molecules

SOME CONCEPT ON BIOCHEMISTRY

• The most abundant molecule in the cell is Water (H2O). Roughly 70% of a cell consists of water.
• Inorganic molecules in the cell are: Sodium chloride (NaCl), potassium chloride (KCl), water (H2O), oxygen (O2) etc.
• Organic molecules to be found in the cell are: Carbohydrates, Fats, Proteins, Nucleic acids
• All organic molecules contain carbon (C) while inorganic molecules can contain any atom except carbon
• They can bond with 4 other atoms allowing them to make rings and chains and thus form large, complex molecules.
• Fats and carbohydrates both contain the same atoms. What distinguishes carbohydrates from fats? In carbohydrates H and O are in the ratio 2:1. There is no such relationship in fats.
• Saturated fats contain the maximum number of hydrogen atoms, come from animals, and tend to be solid at room temp. Unsaturated fats can incorporate more hydrogen into their structures, come from plants and fish (and poultry) and tend to be liquid at room temperature.
• There are 20 different amino acids. Only something like 10 of them (non essential amino acids) is found in sufficient quantities in all plants to provide a balanced diet.  These essential amino acids can not be made in the body. They must be taken into the body in the diet.
• An atom is the simplest building block of matter – elements are made of atoms. Molecules are made of atoms joined together.
• Glucose is a monosaccharide, glycogen is a polysaccharide (and a much bigger molecule); glucose is sweet to taste and dissolves in water, glycogen is not sweet and is insoluble; glucose is used for energy whereas glycogen stores energy.
• Fats provide approximately 2.5 times more energy than carbohydrates – so the butter wins hands down!

Carbohydrates

1. Monosaccharides: Glucose, Galactose, Fructose, Ribose, Glyceraldehyde
2. Disaccharides: Sucrose, Maltose, Lactose
3. Polysaccharides: Starch, Glycogen, Cellulose

CARBOHYDRATE CLASSIFICATIONS

• Carbons No 3 - Triose - Glyceraldehyde, Dihydroxyacetone
• Carbons No 4 - Tetrose - Erythrose
• Carbons No 5 - Pentose - Ribose, Ribulose, Xylulose
• Carbons No 6 - Hexose - Glucose, Galactose, Mannose, Fructose
• Carbons No 7 - Heptose - Sedoheptulose
• Carbons No 9 - Nonose - Neuraminic acid, also called sialic acid

ASSESSMENT OF DEGREE OF DEHYDRATION

• Isotonic dehydration: equal loss of water and electrolytes from the body
• Hypertonic dehydration: More loss of water than sodium ions from the body
• Hypotonic dehydration: More loss of electrolytes than water from the body

AMINO ACID

Each of the 20 α-amino acids found in proteins can be distinguished by the R-group substitution on the α-carbon atom. There are two broad classes of amino acids based upon whether the R-group is hydrophobic or hydrophilic

CLASSIFICATION OF AMINO ACID BASED ON NUTRITION

1. Essential amino acid: The amino acids that are to be supplied through diet are called as essential amino acids. They cannot be produced by the body. Arginine, valine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine and tryptophan.  arginine and histidine are called semi-essential amino acids as they can be partly synthesized in the body
2. Non essential amino acid: The amino acids that can be synthesized by the body are called non essential amino acids. Glycine, alanine, serine, cysteine, aspartic acid, glutamic acid, aspargine, glutamine, tyrosine and proline

CLASSIFICATION OF PROTEINS ON THE BASIS OF THEIR FUNCTIONS

• Enzymes: Proteins that catalyze chemical and biochemical reactions within living cell and outside I.e. DNA- and RNA-polymerases, dehydrogenases etc.
• Hormones - Proteins that are responsible for the regulation of many processes in organisms. i.e. insulin grows factor, lipotropin, prolactin etc.
• Transport proteins - These proteins are transporting or store some other chemical compounds and ions. Some of them are well known:

1. albumin - fatty acid transport in the blood stream
2. haemoglobin and myoglobin - oxygen transport;
3. cytochrome C - electron transport;

• Immunoglobulin or Antibodies - i.e. Probably the clotting of blood proteins, such as fibrin and thrombin
• Structural proteins Collagen, elastin, α-keratin, sklerotin, fibroin - these proteins are involved into formation of the whole organism body.
• Motor proteins. These proteins can convert chemical energy into mechanical energy. Actin and myosin are responsible for muscular motion.
• Receptors Very well known member of this protein family i.e. rhodopsin - light detecting protein.
• Signalling proteins - This group of proteins is involved into signalling translation process. Classical example of this group of proteins is GTPases.
• Storage proteins. These proteins contain energy, which can be released during metabolism processes in the organism. Egg albumin and milk casein are such proteins.
• Zwitterion: This species is termed an amino acid with no ionizable R-group would be electrically neutral at this pH.

CLASSIFICATION OF PROTEINS ON THE BASIS OF THEIR STRUCTURE

1. Simple Proteins: Albumin, Globulin
2. Derived Proteins: Proteoses, Peptones
3. Conjugated proteins: Hb, Casein, Mucin