2'Molecular basis of life

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2. Molecular basis of life
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Chemical basis of molecular interactions

• Polar and nonpolar molecules
• Water
• Universal solvent
• O-H bonds are polarized
• Partial positive and negative charges

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Chemical basis of molecular interactions

• Polar and nonpolar molecules
• Water is polar

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Chemical basis of molecular interactions

• Polar and nonpolar molecules
• Hydrocarbons are nonpolar
• Properties are conferred by functional groups
• A functional group
• Behaves as a unit
• Confers physical properties, chemical reactivity,
  solubility

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Chemical basis of molecular interactions

• Noncovalent bonds
• Not based on electron sharing
• Attractive forces readily broken and reformed
• Major classes
• . bonds
• .. bonds
• interactions and ... forces

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Chemical basis of molecular interactions

• Classification of Bio-Molecules by function
• Macromolecules
• Four major categories
• .
• .
• .
• .
• Metabolic intermediates (metabolites)

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Classification of Bio-Molecules

• Carbohydrates
• . sugars (monosaccharides)
• . .. (oligosaccharides)
• .. .. (polysaccharides)

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Classification of Bio-Molecules

• Carbohydrates
• . (monosaccharides)
• Linking .. by covalent glycosidic bonds
  form
• . (oligosaccharides)
• . ... (polysaccharides)

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Classification of Bio-Molecules

• Carbohydrates
• Linking
• .. by covalent glycosidic bonds

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Classification of Bio-Molecules

• Carbohydrates
• Glycogen
• Branched polymer containing only one type of
  monomer glucose
• Starch in plants
• Amylose
• Unbranched, helical
• Amylopectin

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Classification of Bio-Molecules

• Carbohydrates
• Glycosaminoglycans
• Two different sugars, A-B-A-B-
• Roles in the extracellular space

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Classification of Bio-Molecules

• Take 5

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Classification of Bio-Molecules

• Lipids
• Important categories
• .
• ..

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Classification of Bio-Molecules
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Classification of Bio-Molecules
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Classification of Bio-Molecules

• Lipids
• A molecule may have the same FA or mixed FA
• High energy reserve
• One gram of contains over twice the energy of
  one gram of carbohydrate lack water.
• Stored in specialized cells adipocytes

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Classification of Bio-Molecules

• Lipids
• Steroids
• Built around a characteristic four ring
  hydrocarbon skeleton
• Cholesterol
• Precursor for steroid hormones

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Classification of Bio-Molecules

• Lipids
• Phospholipids
• A diacylglycerol structure
• Third hydroxyl group on the glycerol is
  covalently bonded to a phosphate group then
  linked to a small polar group (eg. Choline)