Macromolecules

Macromolecules

1. Carbohydrates (major energy source)

   • Monomers (Simple)
     • Monosaccharides (C6H12O6)
       • -5 (pentose) or 6 (hexose) carbons
       • Glucose
       • Fructose
         • 2 of carbons are outside of ring
       • Galactose
     • Disaccharides (double sugars)
       • molecules joined by condensation reactions (a water molecule is lost)
       • Maltose (glucose + glucose)
         • -alpha 1-4 linkages -formed by a condensation reaction (lose a water molecule)
       • Sucrose (glucose + fructose)
         • -a.k.a table sugar -most comes from beets
       • Lactose (galactose + glucose)
         • -milk sugar
   • Polysaccharides (Complex)
     • multiple mono/disaccharides join
     • Storage Polysaccharides
       • Starch (plants)
         • -Insoluble -alpha 1-4 linkages
         • Amylose (unbranched)
         • Amylopectin (branched)
       • Glycogen (animals)
         • -insoluble; more branches than amylopectin -stored in liver and muscle tissue (skeletal) -alpha 1-4 + 1-6 linkages
     • Structural Polysaccharides
       • Cellulose (fibre)
         • -linear, unbranched -forms fibrils which reinforce plant cell walls -cannot be digested by animals
       • Chitin
         • -polymer of an amino sugar -makes up exoskeletons -chitin + calcium = hard -semi conductor under certain conditions

2. Proteins (Polypeptides)

   • -50% of dry weight of cells -"molecular tools" -NATIVE CONFORMATION is the shape in which a protein functions best    -assisted by chaperone proteins -proteins can be DENATURED (unfold and become non-functional) by changes in temp, pH, or salt concentration 
   • Primary Structure (DNA blueprint)
     • -sequence of amino acids -determined by a single gene -peptide bonds
   • Secondary Structure (regular, repeated backbone folding)
     • Alpha Helix (H-bonds b/w every 4th peptide bond)
     • Beta Pleated Sheet (H-bonds b/w polypeptide chains)
   • Tertiary Structure (irregular folding of a polypeptide via R-group interactions)
     • -R-group (side chain) interactions -"Globular proteins" b/c chape is irregular and globular
     • H-bonds
     • Ionic bonds
     • disulfide bridge (covalent)
     • Hydrophobic
   • Quaternary Structure (multiple polypeptides)
     • -weak interactions/disulfide bridges (eg -s-s-) -each polypeptide chain is a SUBUNIT of the protein

3. Enzymes (catalysts)

   • -reduce activation energy required for a reaction to occur
   • Thermodynamic Laws
     • 1. total amt of energy in the universe is constant 2. Disorder (entropy) in the universe is always increasing
   • Activation Energy
     • amount of energy required to start a reaction
   • Lock and Key Theory
     • -one enzyme (loc) has a specific shape for one set of substrates (key)
   • Induced-Fit Theory
     • -shape of the active site changes somewhat after substrate(s) bind to it
   • Competitive Inhibition
     • -"look-alike" molecule binds to active site -enzyme unable to bind with substrate -enzymes inactivated
     • Penicillin
       • kills succeptible bacteria by inhibiting the enzyme that catalyzes the final step in cell wall biosynthesis
     • ACE Inhibitors
       • Inhibit enzymes that make angiotensin II hormone (constricts blood vessels)
     • Ethanol
       • antidote for methanol poisoning
     • Grapefruit
       • Inhibit a drug-metabolizing enzyme in the small intestine
   • Non-Competitive Inhibition
     • Molecules bind to a site adjacent to active cite and change the shape of the active site
     • Eg) Heavy metals
   • Allosteric Regulation
     • Molecules bind to a site AWAY from active site
     • Allosteric activation
     • Allosteric deactivation
     • Co-enzyme (vitamin aiding enzyme's action)
     • Co-factor (mineral aiding enzyme's action

4. Lipids (Energy and Structure)

   • -C, O, H (no ratio) -hydrophobic
   • Fats and Oils
     • *Glycerol + 3 Fatty Acid chains *joined by ester linkages
     • Saturated Fatty Acids
       • -solid at room temp *Every carbon bond holds a Hydrogen -eg) animal fats
     • Unsaturated Fatty Acids
       • -liquid at room temp *Some double bonds (more double bonds = healthier)
       • Monounsaturated (1 double bond)
       • Polyunsaturated (more than 1 double bond)
       • Cis isomer (H's on same side)
       • Trans isomer (H's on opposite side)
   • Phospholipids
     • -fat derivitives -important in cell membranes *AMPHIPATHIC (hydrophobic + hydrophillic regions)
     • Hydrophilic head
     • Hydrophobic tails
       • -2 fatty acid chains
   • Sterols
     • -flat ring structure of carbons
     • Cholesterol (most common)
       • -found in cell membranes -makes membranes less permeable
       • High-density Lipoprotein (good)
       • Low-Density Lipoprotein (bad)

5. Nucleic Acids / Polynucleotides (Structure, Functional)

   • -in nucleus and mitochondria -polymers of nucleotides
   • Nucleotides
     • Consists of:
       • a nitrogen base
         • Pyrimidines (single ring)
           • Thymine (DNA) / Uracil (RNA)
           • Cytosine (DNA & RNA)
         • Purines (double ring)
           • Adenine (DNA & RNA)
           • Guanine (DNA & RNA)
       • a 5-carbon sugar
         • Deoxyribose (DNA)
         • Ribose (RNA)
       • a phosphate group
     • 2 types
       • Deoxyribonucleic Acid
         • -Chemical basis for the gene -found in nuclei of cells
       • Ribonucleic Acid
         • -close copies of genes -found in cytoplasm

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