Download - 4.2 carbohydrates
CHAPTER 4CHAPTER 4
CHEMICAL CHEMICAL COMPOSITION OF THE COMPOSITION OF THE
CELLCELL
4.2 CARBOHYDRATES4.2 CARBOHYDRATES
Nur amni syazanaNur amni syazana
CARBOHYDRATES• Source of energy• Build cell walls of plants• Form external skeleton of insects• As food storage• Consists of carbon,hydrogen and oxygen• Ratio of hydrogen atoms to oxygen atoms
molecule is 2:1
TYPES OF CARBOHYDRATES
MONOSACCHARIDES
POLYSACCHARIDES
DISACCHARIDES
MONOSACCHARIDESThe basic building blocks of carbohydrates
(monomers of carbohydrates) Known as simple sugarReducing sugars
EXAMPLE:Glucose ~ in plants and fruitsFructose ~ in sweet fruits and
honeyGalactose ~ in milk
DISACCHARIDESReducing sugars except sucroseConsist of two monosaccharidesComplex sugars
EXAMPLE:GLUCOSE + GLUCOSE -> Maltose (malt sugar)GLUCOSE + FRUCTOSE -> Sucrose (cane sugar)GLUCOSE + GALACTOSE -> Lactose (milk sugar)
GLUCOSE + GLUCOSE ------------------->MALTOSE + WATER condensation
GLUCOSE + GLUCOSE <-------------------MALTOSE + WATERhydrolysis
POLYSACCHARIDESCombination of hundreds of monosaccharidesFormed by the condesation of glucose monomersDo not taste sweet and do not crystalliseInsoluble in water
EXAMPLE:Glycogen ~ in animal and yeast
~ known as animal starch
Starch ~ stores in plants (rice,corn,bread,wheat)Cellulose ~ form cell wall in plants
GLUCOSE + GLUCOSE ------------------->MALTOSE + WATERhydrolysis