Download
1 / 100
1.01k likes | 1.46k Views
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)
E N D
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”
Resource • This lecture • Campbell and Farrell’s Biochemistry, Chapter 16
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 • By the number of sugars that constitute the molecule • 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
Numbering order of compounds with more than one functional group Carboxylic acid Aldehyde Ketone Alcohol Amine Alkyne = alkene Alkane
Classification 2 • By the number of carbon atoms they contain • Triose • Tetrose • Pentose • Hexose • Heptose
Glyceraldehyde Chiral carbon
Structural isomers • Same number of atoms, different connectivity
Stereoisomers Same number of atoms and connectivity, but not superimposable
Number of possible stereoisomers • 2n (n is the number of chiral carbons in a sugar molecule)
Stereoisomers, but non-mirror images and non-superimposable, then…diastereomers OH H H OH
Diastereomers that differ in the orientation of one chiral carbon…epimers
Acetal/ketal vs. hemiacetal/hemiketal Hemiacetal and hemiketal: ether and alcohol on same carbon Acetal and ketal: two ethers on same carbon What is the difference between hemiacetal and hemiketal and the difference between acetal and ketal?
