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Chapter 3: The Chemical Basis of Life II: Organic Molecules - Coggle…

- - - - cis-trans isomers = cis if functional groups are on same side of carbons, trans if they are on opposite sides
      - enantiomers = molecules that exist as mirror images
- - - - fats (triglycerides) are formed when glycerol bonds to three fatty acids
        
        in a saturated fatty acid, all carbonds are linked by single covalent bonds
        
        in an unsaturated fatty acid, there can be one or more C=C double bonds
      - phospholipids are similar in structure to triglycerides, except that one glycerol is linked to a phosphate group instead of a fatty acid
        
        phospholipids contain hydrophilic and hydrophobic regions, making them amphipathic and allowing them to form a bilayer
      - steroids are constructed of four fused rings of carbon atoms
        
        a small difference in their structure can lead to huge differences in its characteristics (e.g., difference between estrogen & testosterone)
      - waxes are non-polar and exclude water
        
        they are often found as protective coatings on leaves and the outer surfaces of animals' bodies
  - - - polysaccharides such as starch (in plants) and glycogen (in animals) store energy
      - polysaccharides such as cellulose have a structural function
  - - - four levels of protein structure:
        
        primary
        
        amino acid sequence
        
        secondary
        
        alpha helices or beta pleated sheets
        
        tertiary
        
        folding into a 3D shape
        
        quaternary
        
        two or more polypeptides
  - - - DNA molecules consist of two strands of nucleotides coiled together in a double helical shape
        
        the strands are held together by hydrogen bonds between a purine base (A or G) on one strand and a pyrimidine (T or C) base on the other. A-T, G-C.
      - RNA consists of a single strand of nucleotides
        
        the sugar in each nucleotide is ribose instead of deoxyribose
        
        instead of a thymine base, RNA has uracil
        
        RNA molecules are involved in deciphering information in a DNA sequence into instructions that link amino acids in a sequence to form a polypeptide
    - - each nucleotide has a phosphate group, a five-carbon sugar (deoxyribose or ribose) and a base (single or double ring of carbon and nitrogen atoms)