Biomolecules - Shobhit Nirwan PDF

All chemical reaction in a cell Nutrient – Carbohydrate ( Glycosidic Bond ) Protein (Peptide) Lipid (Ester) Removal of CO2 from amino acid to form amine Removal of amino group in a nucleotide base Hydrolysis of glycosidic bond The organic compounds ta...

All chemical reaction in a cell Nutrient – Carbohydrate ( Glycosidic Bond ) Protein (Peptide) Lipid (Ester) Removal of CO2 from amino acid to form amine Removal of amino group in a nucleotide base Hydrolysis of glycosidic bond The organic compounds taking part in metabolism is called metabolites. They are of two types:- Primary Metabolites They have identifiable functions in psychological processes and necessary for life. Example amino acids, nucleic acids, sugars, lipids, vitamins, etc. Secondary Metabolites They are not directly involved in the normal growth, development or reproduction of organism. Example essential oils, toxins, pigments, lectins, drugs, etc. Metabolic pathways are similar to the automobile traffic in a city. Flow of metabolites through the metabolic pathways has a definite rate and direction like automobile traffic. This metabolic flow is called the dynamic state of body constituents. There are two types of metabolic pathways: Anabolic (biosynthetic) pathways and Catabolic pathways Anabolic (Biosynthetic) pathways Catabolic pathways Simpler molecules form complex structures Complex molecules become simple structures (constructive process) (destructive process) It consumes energy It releases energy Example: formation of acetic acid from Example: formation of lactic acid from glycose cholesterol, assembly of amino acids to protein, (glycolysis) respiration photosynthesis The energy released through catabolism is stored in the form of chemical bond. When needed, this bond energy is utilised for biosynthetic, osmotic & mechanical works. The most important energy currency in the living system is the bond energy in adenosine triphosphate (ATP)  Enzymes are biological catalysts which influence the speed of biochemical reactions OR They are biological catalyst that speed up the rate of reaction without being involved All enzymes are proteins but all proteins are not enzymes The chemicals on which the enzyme acts are called substrate Enzyme converts substrates into products Enzymes are specific, i.e., each enzyme has its own substrate Enzymes get damaged at high temperature Enzymes lower the activation energy of the reaction Enzymes isolated from thermophilic organism (live under high temperatures) are thermostable Enzymes form tertiary structure (3D) with some crevices (pockets) called ‘active site’ into which the substrate fits Nucleic acids (RNA) that behave like enzymes are known as Ribozymes Carbonic anhydrase is the fastest enzyme. It accelerates the following reaction 10 million times In the absence of the enzyme, only 200 molecules of 𝐻2 𝐶𝑂3 are formed in an hour. In presence of carbonic anhydrase, about 600,000 molecules are formed per second! In a multistep chemical reaction (metabolic pathway), each step is catalysed by different enzymes Example: In glycolysis {Glucose (𝐶6 𝐻12 𝑂6 ) → 2 pyruvic acid 𝐶3 𝐻4 𝑂3 )} 10 difference enzymes take part In a chemical reaction, there will be breaking of bonds. 𝐵𝑎(𝑂𝐻)2 + 𝐻2 𝑆𝑂4 → 𝐵𝑎𝑆𝑂4 + 2𝐻2 𝑂 (inorganic chemical reaction) 𝑆𝑡𝑟𝑎𝑐ℎ + 𝐻2 𝑂 → Glucose (organic chemical reaction) Rate of reaction = amount of product formed / unit time