CHAPTER 4 : CHEMICAL COMPOSITION OF THE CELLCHAPTER 4 : CHEMICAL COMPOSITION OF THE CELL

CARBOHYDRATESCARBOHYDRATES

Contain the element carbon, hydrogen & Contain the element carbon, hydrogen & oxygenoxygen

3 main groups : monosaccharides, 3 main groups : monosaccharides, disaccharides & polysaccharidesdisaccharides & polysaccharides

MonosaccharidesMonosaccharides

Basic building blocksBasic building blocks Simple sugar as glucose, fructose & Simple sugar as glucose, fructose &

galactosegalactose Consist of single chemical group made up Consist of single chemical group made up

of a ring of carbon, hydrogen & oxygen of a ring of carbon, hydrogen & oxygen atomsatoms

Reducing sugarsReducing sugars Can be detected by using Benedict’s test.Can be detected by using Benedict’s test.

DisaccharidesDisaccharides

Complex sugarsComplex sugars Consist of Consist of two monosaccharidestwo monosaccharides

combined chemically through combined chemically through condensationcondensation..

Mono + mono Mono + mono disaccharides + water disaccharides + water Eg.: maltose (malt sugar), sucrose (cane Eg.: maltose (malt sugar), sucrose (cane

sugar), lactose (milk sugar)sugar), lactose (milk sugar)

Disaccharides (continue...)Disaccharides (continue...)

Glucose + glucose Glucose + glucose maltose + water maltose + water Glucose + fructose Glucose + fructose sucrose + water sucrose + water Glucose + galactose Glucose + galactose lactose + water lactose + water

Can be broken down into Can be broken down into monosaccharides through monosaccharides through hydrolysishydrolysis

All are reducing sugar except sucrose All are reducing sugar except sucrose

PolysaccharidesPolysaccharides Large complex sugarLarge complex sugar Many monosaccharides are joined Many monosaccharides are joined

together to form long chain of simple sugar together to form long chain of simple sugar called called polymerspolymers..

Eg. : starch, glycogen & celluloseEg. : starch, glycogen & cellulose