Carbohydrates The most common building material on Earth Made of Carbon Hydrogen and Oxygen (Most have the ratio 1:2:1 for C:H:O) Used as energy source, building material & cell surface markers There are three major types

1.Monosaccharides (simple sugars) made of single carbon chain with hydroxyl attached dry state is linear wet state (dissolved) is ring

Monosaccharides distinguished by carbonyl group ie aldehyde – aldose sugar, ketone – ketose sugar

Monosaccharides Isomer – a molecule with the same chemical formula but with different arrangement of atoms (pg31 Fig 8(b)) α Glucose β Glucose

2.Dissaccharides (Oligiosaccharides) made up of 2 sugars (monosaccharides) subunits are attached by a linkage called GLYCOSIDIC LINKAGE which is made by condensation reaction (pg. 31 Fig 8 a&b)

Why do glycosidic linkages have numbers in them? Remember when we said that functional groups are more reactive and therefore more important than the C-H bonds? We number the carbons starting closest to the functional group

Two glucose molecules have come together to form a maltose molecule. What is the linkage called? 1-4 glycosidic linkage Explain why this is a 1-2 glycosidic linkage.

3. Polysaccharides (complexcarbohydrates) made of 100’s and 1000’s of monosaccharides can be straight chained or branched serve 2 functions – energy storage (starch, glycogen) structural support (cellulose, chitin)

Polysaccharides Starch – (How plants store energy) –there are 2 types Amylose – unbranched α glucose polymer with an α 1-4 glycosidic linkage Amylopectin – branched α glucose polymer with an α 1-4 glycosidic linkage α 1-6 glycosidic linkages cause the polymer to twist into coils making it insoluble in water

Polysaccharides - starch amylopectin

Polysaccharides B. Glycogen One way animals store energy (in muscle and liver cells) 1-4 glycosidic linkages similar to amylopectin but more branches Glycogen in liver cells Glycogen

Polysaccharides Cellulose – major polysaccharide of plants straight chain polymer of β glucose held by alternating alpha and beta 1-4 glycosidic linkage (which makes it indigestible) not coiled so form tight bundles called microfibrils