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CHAPTER 4 : CHEMICAL COMPOSITION OF THE CELL4.1 The chemical composition of the cell

carbohydrates

Elements in CarbohydratesFormed by C,H and ORatio C:H:0 is 1:2:1Sub unit CH2OFormula (CH2O)n

Formation & breakdown of disaccharidesglucose+sucrosecondensation+ H2Ohydrolysis

fructose

Formation & breakdown of disaccharidesglucose+maltosecondensation+ H2Ohydrolysis

glucose

Formation & breakdown of disaccharidesglucose+lactosecondensation+ H2Ohydrolysis

galactose

glucoseglycogenCondensation reaction (-H2O)Hydrolysis (+ H2O) disaccharideStarch moleculeCondensation reaction (-H2O)Hydrolysis (+ H2O) celluloseCondensation reaction (-H2O)Hydrolysis (+ H2O)

POP QUIZ !!!Fill in the blanks with the correct answer

Formation & breakdown of disaccharidesa) _____+sucrosecondensation+ H2Ohydrolysis

b)______

Formation & breakdown of disaccharidesglucose+a)____________condensation+ H2Ohydrolysis

glucose

Formation & breakdown of disaccharidesa)______+b)____________c)______________+ H2Od)____________

galactose

protein

Elements in proteinCarbon, hydrogen, oxygen, nitrogen, sulphur & phosphorusBasic unit: amino acidsAmino acids are joined to each other in a particular sequence to form polypeptide chain or protein

Formation and breakdown of dipeptides & polypeptides

+condensationhydrolysisPeptide bond+H2OAminoacidAminoaciddipeptide

+condensationhydrolysis++

2H2OAminoacidAminoacidAminoacidtripeptide

condensationhydrolysis

A polypeptide chain+ 9H2O* 10 to 100 amino acids

Protein StructuresComplete protein molecule is a simple unbranched chain of amino acids3D protein structure is classified into 4 levels:Primary structureSecondary structureTertiary structureQuaternary structure

Essential amino acids & Non essential amino acidsEssential:Amino acid that required for protein synthesis, but cannot be synthesized in the human bodyObtained from food we eat

Non essential:Amino acid that is required for protein synthesis and can be synthesized by humans

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