CarbohydratesMonosaccharidesandDisaccharides

Lesson aims

•Describe with the aid of diagrams the formation and breaking of glycosidic bonds in the synthesis and hydrolysis of a disaccharide (maltose) and a polysaccharide (amylose)

Condensation

What words do you associate with this?

• Water molecules is released• New covalent bond is formed• Larger molecule is formed by bonding of smaller

molecules

• 2 H removed and 1 O Which forms water

• Glycosidic bond• Covalent bond is formed- electrons are shared

Range of Carbohydrates and Functions

Monosaccharides Disaccharides Polysaccharides

ALL contain the elements:

Monosaccharide Chemical Formulae

C6H12O6

H

C

C C

C

C

C

O H

O HH

H

H

HH

H

HH

HOO

O

O

Different Forms of Glucose

Alpha glucoseα - glucose

Beta glucoseβ - glucose

Building and Breaking Disaccharides

H2O removal

condensation reactionadd H2O

α-glucose

α-glucose

maltose

glycosidic link

hydrolysis reaction

Try building more disaccharides:

β - glucoseβ - glucose

cellobiose

α - glucose

α-fructose sucrose

Maltose has an α-1,4 glycosidic link.What do the numbers refer to?

What type of glycosidic links are found in cellobiose and sucrose?

Understanding Diagnostic TestsReducing Sugars

+ Benedict’s reagent boil

Understanding Diagnostic TestsNon - Reducing Sugars

+ Benedict’s reagent boil

sucrose

Apple juice is predicted to contain both reducing and non-reducing sugar. Design an investigation todetermine whether this prediction is valid. Can you make your analysis quantitative?