Themes Main Lecture Three
Water's essential properties
H-bonding High Heat of evaporation High Heat capacity
Aqueous Reactions
Precipitation Acid-Base ( Buffers) Redox
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Macromolecules Chapter 3
Molecules in living organisms: proteins, carbohydrates, lipids, nucleic acids Most are polymers of smaller molecules called monomers.
Macromolecules: polymers with molecular weights >1000
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Most are polymers of smaller molecules called monomers.
Polymer
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Quantitative analysis
Macromolecules: polymers with molecular weights >1000
-1 mole =6.022 x 1023 atoms. -1 mole Na weighs 23 grams (see periodic chart) 1 mole NaCl= 23g + 35g=58g or the MW of NaCl is 58g/mole (Daltons) So, 1 mole of NaCl has 6.022 x 1023 NaCl molecules
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I. Proteins
General Structure of Amino Acids
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Zwitterionic form of amino acids
Under normal cellular conditions amino acids are zwitterions (dipolar ions):
Amino group = Carboxyl group =
-NH3+ -COO-
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Functional groups (R): groups of atoms with specific chemical properties and consistent behavior; it confers those properties when attached to large molecules ( see fig. 3.1 Book).
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H-bonding
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1. Glycine---flexibility, allows tight packing 2. Proline----kinks, twist in secondary structures 3. Cysteine---stability of intra/inter molecular structures
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There are 20 naturally occurring amino acids: 20100
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A
B
A
B
A configuration
A Isomers
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Amino configuration
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Optical acids bond together covalently by peptide bonds to form the polypeptide chain.
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The primary structure of a protein is the sequence of amino acids.
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The sequence determines secondary structure.
Configuration Restrictions
1. Nature of peptide bond 2. R groups
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R-Functional Groups
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The sequence determines secondary and tertiary structure (how the protein is folded ) and quaternary structures.
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Disruption of the inter/intra molecular forces
Denaturation: loss of 3-dimensional structure and thus function of the protein
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Conditions that affect secondary and tertiary structure:
High temperature pH changes High concentrations of polar/non-polar molecules Biologically extreme conditions
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Some Protein Folding Is Assisted by Chaperones
Folding rate and integrity prevent incorrect aggregation
heat shock proteins
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II Carbohydrates
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General Structure of Carbohydrates monomers
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Fig 8.4 Fisher projections of L- and D-glucose Still monosaccharide
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Main Themes Lecture four
Macromolecular Molecules-proteins, lipids, carbohydrates and nucleic acids. Monomers to polymers (large structures) I Proteins Amino acids to polypeptides (proteins): Primary, secondary, tertiary and quaternary Remember these have essential functions II Carbohydrates Monsaccharides to polysaccharides (carboydrates)
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