Topic 4: Carbohydrates

Carbohydrates

• includes sugar and polymers of sugar

• contain a carbonyl group and many hydroxyl groups

• comprised of C, H and O

Monosaccharides: simple sugars

-molecular formulas with multiple of the units CH2O

• most common is glucose

• nutrients and fuel for cells

• used in cellular respiration

Can serve as building blocks for amino acids, or as monomers for di- and polysaccharides.

Disaccharides: two monosaccharides joined together by covalent bonds

—> most common is sucrose

building blocks of sucrose: glucose and fructose

• plants transfer carbohydrates from roots to leaves in the form of sucrose

Polysaccharides: polymer with many sugars joined via dehydration synthesis

Plants store starch ( polymer of glucose monomers)

• allows plants to store excess glucose

Animals store glycogen ( polymer of glucose)

• stored in the liver and muscle cells

structural polysaccharides

• cellulose: tough substance that forms plant cell walls

• chitin: forms exoskeleton of arthropods