Dr Praveen Kumar Agrawal is teaching live on Unacademy Plus
COURSE BIOMOLECULES Lesson Formation and degradation of macromolecules (Basic concepts) Dr. Praveen Kumar Agrawal
Polymerisation, dehydration synthesis and hydrolysis . Polymerisation is a dehydration synthesis in which there is a joining of many similar and smaller units to form a large unit. The smaller units are called monomers and the larger unit is called polymer. It is similar to the construction of a wall. Wall is formed by joining a number of bricks by cementing material. The wall is the polymer and the bricks are the monomers. The monomeric units in a polymer are held together by means of a particular bond. Examples Glucose (monomer) units are held together by glycosidic bond to form starch (polymer). . Amino acids (monomers) are joined together by peptide bonds to form polypeptide chain or protein Nucleotides (monomer) are cemented together by phosphodiester bond to form polynucleotide chain. . In biological systems, almost all polymers are formed as a result of dehydration synthesis, i.e., formation of molecules, with the removal of water, e.g., if two glucose molecules (C6H1206) are added together, the resultant compound is maltose (C12H22011). This molecule is formed with the removal of a water molecule. Similarly when (n) number of monomers are added together, (n-1) number of water molecule:s are removed off. . Opposite of 'dehydration synthesis' is called 'hydrolysis'. This involves the breaking down of polymer into its simpler forms (monomers). This breakage requires the water molecules. Hence this is called hydrolysis (Hydro water, lysis breakdown).
CH2OH CH2OH CH2 OH CH2 OH OH +HO OH -H2O OH OH OH OH OH OH Glucose Maltose Glycosidic bond
CH3(CH mitic cid 0 H + HO CH (CH2 ba CH3 H3(CH2)14 co C pal (be Ha 24 Oly -H20 20 Palmitic acid Hexacosonol Hexacosyl palmitate (beewax) itat HOOC-CH NHH + HOOC-CH NHH H20 Peptide bond