Carbon Chemistry: The Molecular Diversity of Life and The Structure and Function of Large Biological Molecules

Essential Elements of Life Of the 92 naturally occurring elements, only ~20% are essential for life Different organisms require different types of elements 96% of human body is made up of O, N, C, H The others are known as Trace elements

Organic Chemistry (<3) Organic = Carbon (C) Organic chemicals were thought to be those that arise from living organisms Urey and Miller (1953) showed that organic compounds can be made from abiotic sources

Miller’s experiment supported the idea that organic compounds, thought only to be contained in living organisms, could be synthesized in the primitive conditions of early Earth. Urey and Miller Experiment – Life from Non-life

Carbon: The element of life 4 valence electrons Each atom can generate 4 covalent bonds Can bond with other C or other elements – diversity!

Hydrocarbons Consist only of C and H Not prevalent in living organisms But many organic molecules have hydrocarbon regions Contain large amounts of energy in these bonds

Hydrocarbon Diversity

Saturated vs. Unsaturated Double bonds change the structure! Effects the chemistry of the compound! Changes melting and boiling points

Isomers Compounds with the same number of atoms of the same elements but different structures. Differences in structure lead to different properties. 3 types: Structural, cis-trans, enatiomers

Structural Isomers Arrangement of atoms vary, but same molecular formula The number of possible isomers increases with number of C in skeleton

Cis and Trans Isomers Double covalent bond between 2 C creates inflexibility. The remaining 2 bonds have different spatial arrangements due to inflexibility. Cis = same side Trans = opposite sides

Enantiomers: L and D Enantiomers are mirror images of each other due to an asymmetric C (because of 4 different bonds) Enantiomers become important when discussing biochemistry – only 1 form is typically “active”