BIOCHEMISTRY OF CELL L NO.3

INTRODUCTION Major function of cell- metabolic activities Anabolic reaction- biosynthesis of a new cellular material takes place. Catabolic Reaction- complex product is hydrolyzed & broken down into smaller & simpler molecules.

BASIC CHEMICAL CONSTITUENTS OF CELL Carbohydrates Proteins Lipids Nucleic Acid Enzymes

CARBOHYDRATES

ROLE OF CARBOHYDRATES To provide energy Monosaccharide like glucose is main substrate for synthesis of ATP. In mammals, disacch. Lactose present in milk provides energy to their babies. Polysacch,… serve as structural component of cell membrane, cell wall ( cellulose) & reserve stored material (starch).

PROTEINS Long chain of A.A One end-amino -NH2 Other end - C-terminal

List of Amino acids

Classification of Proteins (Nature) Simple Proteins Conjugated Composed of simple amino acids. Eg: histones, zein- maize Simple proteins + nonprotein part. Nucleoproteins- proteins + nucleic acids Glycoproteins- pro+ Carb-ohydrates Chromoproteins- pro+pigments

Proteins Role Act as: Enzymes- all enzymes are proteins but all proteins are not enzymes. Eg- amylase Hormones- insulin, growth hormone are proteins

Classification of Proteins (Structure) Contractile Proteins Transport Proteins Defensive Proteins Occurs in muscles Eg: Myosin Useful in transportation of material Eg: Haemoglobin-transfers O2 Myoglobin-transfers-O2 in muscles. Protection of body against diseases Eg: Antibodies, thrombin-blood clot On basis of structure

LIPIDS Coined by BLOOR They are group of organic components having oily or greasy consistency. Fats, oils, steroids, waxes are lipids. Fats in animal is in solid state while in plants it is liquid state, hence called oils. Waxes are produced by both plants & animals. Insoluble in water, soluble in polar solvents like benzene, chloroform etc Composed of C,H,O generally & compound lipids have N,S,P.

Classification of Lipids Simple- Saturated – single bond- eg: Palmitic acid Unsaturated- double bond- eg:oleic acid Derieved-Steroid- eg: cholesterol, bile salts, sex hormones Waxes- plant & animal wax Carotenoids- eg- α & β carotene, xanthophyll Compound- eg- phospholipds, glycerophospholipid glycolipid

Simple lipids These are esters of fatty acids with alcohol. Glycerol is 3 carbon alcohol with 3 –OH groups. Depending upon no of fatty acid group attached glycerides are of following type: Mono-glyceride Di-glyceride Tri-glyceride Fatty acid is a long chain of C atoms with carboxyl group at one end.

Compound Lipids Fatty acid+ alcohol+ N/P/S/proteins. Eg: phospholipids, Glycerophospholipids, glycolipids Phospholipids are imp for cell memrane

NUCLEIC ACID 2 Types: a) DNA b) RNA Composed of Nucleotides Nucleotides= Ribose/deoxyribose + Nitrogenous base + Phosphoric acid

Nucleotide & Nucleoside

N bases

Structure of DNA

RNA

Types of RNA

ENZYMES Reaction Small Amount Active site of enzyme Amphoteric Nature Specificity Colloidal nature Enzyme optima

Active site of enzyme

Factors Affecting Enzyme Activity Temperature pH Substrate Concentration Inhibitors- Competitive Non- competitive

Competitive & Non Competitive Inhibitors

TYPES OF ENZYMES

CO-FACTORS Non protein constituents which make an enzyme catalytically active is called cofactor. They are also called as Prosthetic group( non protein part) Eg :Vitamins

CONCEPT OF METABOLISM The sum total of all biochemical processes is called metabolism.

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