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Objectives
- Recognize the different mono- and disaccharides
- Explain how polysaccharides form
- Discuss how structure and function relate for carbohydrates
Key points
- store energy and build structures
- made of C, H, O in (CH2O)n proportion
- monosaccharides have at least 3 carbons, up to 7
- all include a carbonyl group (C=O) and -OH groups
- properties depend on arrangement of groups, size of carbon chain
- aldoses have the carbonyl at the end of chain, while ketoses have the carbonyl carbon in the middle of the chain
- isomers are molecules that have the same formula but different shapes
- glycosidic bonds result from dehydration reactions, form polymers
- described by position of bond, orientation
- dissacharides are composed of 2 monosaccharides
- polysaccharides store energy, provide structure
- polysaccharides also act as cell surface markers
In-class activities
- Carbohydrates are everywhere, forming the foundation of the biological economy. Think about the foods you ate yesterday and list them. For each food, list each carbohydrate and whether it is a monosaccharide, disaccharide, or polysaccharide (hint: ‘fiber’ is a polysaccharide that is not digestible). Then explain the function of that carbohydrate in the organism that originally synthesized it. Finally, estimate how many calories it provided to you when you ate it.
- Why does candy make you thirsty?