Carbohydrates

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Carbohydrates
Lecture 15. Carbohydrates 1
Lecture 14. Subunit Interactions and Quaternary
Structure 1
Lecture 14. Subunit Interactions and Quaternary
Structure 1
Lecture 14. Subunit Interactions and Quaternary
Structure 1
Lecture 14. Subunit Interactions and Quaternary
Structure 1
Lecture 14. Subunit Interactions and Quaternary
Structure 1
Lecture 1. Introduction to Biochemistry
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• most abundant organic molecules in nature

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IMPORTANCE

• Photosynthesis stores energy in carbohydrates
• Carbohydrates are the metabolic precursors of all
  other biomolecules
• Important component of cell structures
• Important function in cell-cell recognition

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Carbohydrate Classes

• Monosaccharide
• Simple sugars, can not be broken down further
• general formula (CH2O)n
• Examples

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Alpha vs Beta glucose
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• Can be
• Aldoses
• Contain aldehyde
• Ketoses
• Contain ketones

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• Disaccharide - two sugars
• formed by dehydration synthesis

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• glucose fructose ? sucrose water
• table sugar
• glucose galactose ? lactose water
• milk sugar
• glucose glucose ? maltose water
• malt sugar

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Carbohydrate Classes
Lecture 15. Carbohydrates 8

• Disaccharides
• Simplest oligosaccharides
• Contain two monosaccharides linked by a
  glycosidic bond

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Oligiosaccharide

• short chain 3 -10 monomers long
• Identification on cells

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Carbohydrate Classes

• Polysaccharides
• Polymers of monosaccharides

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Polysacchrides
Lecture 15. Carbohydrates 11

• Starch and glycogen are storage molecules
• Chitin and cellulose are structural molecules
• Cell surface polysaccharides are recognition
  molecules.

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Polysacchrides
Lecture 15. Carbohydrates 12

• Glucose is the monosaccharides of the following
  polysacchrides with different linkages and
  banches
• a(1,4), starch (more branch)
• a(1,4), glycogen (less branch)
• b(1,4), cellulose (cell walls of all plants)
• b(1,4), Chitin similar to cellulose, but C2-OH is
  replaced by NHCOCH3 (found in exoskeletons of
  crustaceans, insects, spiders)

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Carbohydrates

• Polysaccharide - glycogen
• many glucose units in a branching pattern
• liver and skeletal muscle are good sources
• hormone insulin stimulates glycogen production
  (glycogenesis)
• hormone glucagon stimulates glycogen breakdown
  (glycogenolysis)
• glycogen is found in animal cells as an inclusion

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Carbohydrates

• Starches are complex carbohydrates, often two
  polysaccharide chains
• plants make starches, including the indigestible
  cellulose
• examples - wheat, rice, corn, potato, cassava,
  rye, barley