Chemistry of Life

  • INORGANIC - DOES NOT CONTAIN H BONDED TO C

Water:

  1. Versatile solvent

    1.    solvent for compounds and polar molecules - hydrophilic substances

  2. cohesive and adhesive

    1. adheres to charged surfaces - transport system

  3. high specific heat capacity

    1. h-bonds must be overcome to change state, resists temp change

  4. high heat of vapourization

    1. water cools surfaces as it evaporates

  5. ice is less dense than water

    1. insulation

CARBOHYDRATES (CHO):

  • hydroxyl group is polar —> H bonds in water

  • Monosaccrides

    • glucose, fructose, and galactose

    • joined through dehydration synthesis

  • Disaccarides

    • glycosidic bond —> stores energy —> broken by hydrolysis

      • glucose + glucose = maltose

      • glucose + fructose = sucrose

      • glucose + galactose = lactose

  • polysaccarides

    • starch

      • long branched chains, plants

    • glycogen

      • short term storage in animals, short chain, many branches

    • cellulose

      • insoluble carb, cell walls

      • long chains linked by H-bonds —> bundles called microfibrils

      • indigestible beta bonds

    • Chitin

      • N functional group instead of hydroxyl, exoskeletons

NUCLEIC ACIDS (CHNOP):

  • DNA

  • RNA

    • A + G = PURINE

    • T + C = PYRIMIDINE

      • “pure as gold”

PROTEINS (CHONS):

  1. fibrous - parallel strands - structural

  2. Globular - functional

  • levels of protein organization

    • primary structure

      • polypeptide chain

    • secondary structure

      • alpha helix/beta sheet

    • tertiary sturucture

      • hydrophilic/phobic interactions + bonds between R groups

      • disulfide bridges between R groups of cystine

    • Quaternary structure

LIPIDS (CHO):

  • monomers are tightly packed - no bonds

  1. fats, oils, and waxes

    1. long term energy storage, insulation around major organs

    2. large proportion of hydrogen, big potential energy release

  1. fatty acid —> hydrocarbon chain ending in a carboxylic acid group (-COOH)

  2. Triglyceride

  • formation = 3 fatty acids + 1 glycerol (alcohol)

  • ester linkage

  1. neutral fat = non-polar

Saturated:

  • strong attraction

  • closely packed

  • high melting point

  • solid at room temp

  • animal origin

Unsaturated:

  • low melting point

  • less attraction between chains

  • plant origin

Phospholipids

Polar head - phosphate group, nitrogen-containing, hydrophilic

Waxes:

  • saturated fatty acids convalently bonded to long chain alcohols

  • highly saturated + hydrophobic

Steroids

  • lipids with a backbond of four fused carbon rings