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Macromolecules & Carbohydrates. Lecture 3 Dr. Mamoun Ahram. Cell's weight. Subunits. Subunits: the small building blocks (precursors) used to make macromolecules Macromolecules: large molecules made of subunits . Macromolecules. Carbohydrates (monosaccharides) Proteins (amino acids)
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Macromolecules& Carbohydrates Lecture 3 Dr. Mamoun Ahram
Subunits • Subunits: the small building blocks (precursors) used to make macromolecules • Macromolecules: large molecules made of subunits
Macromolecules • Carbohydrates (monosaccharides) • Proteins (amino acids) • Nucleic acids (nucleotides) • Lipids (fatty acids) • Except for lipids, these macromolecules are also considered polymers
How water is removed? • Mechanism 1: One subunit contributes an “H” and the other subunit contributes an “OH” • Mechanism 2: One subunit contributes 2 “H” the other subunit contributes an “O”
What are they? • Carbohydrates are polyhydroxy aldehydes or ketones • Saccharide is another name for a carbohydrate
Functions • Source of energy • Structure (cellulose and chitin) • Building blocks • Cellular recognition
Classification I • Monosaccharides • Disaccharides • Oligosaccharides • Polysaccharides
Monosaccharides • Basic chemical formula: (CH2O)n • They contain two or more hydroxyl groups
Drawing sugars • Fisher projections or perspective structural formulas Forward Backward Top (C1): Most highly oxidized C
Classification 2 • By the number of carbon atoms they contain
Glyceraldehyde Chiral carbon
Number of possible stereoisomers • 2n (n is the number of chiral carbons in a sugar molecule)
Sugar esters (esterification) • What is the reacting functional group? Where does it react? What are the end products? Where are they used?
Sugar acids (oxidation) • Where is it oxidized? What does it form?
Note • Oxidation of ketoses to carboxylic acids does not occur