Class09

Class09 - Chemistry 83 Class09 1 Chemical Evolution From...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chemistry 83 Class09 1 Chemical Evolution From volcanic gases to micro- molecules (the precursors for biological molecules) What is chemical evolution? Chemical evolution is the natural conversion of smaller molecules to large biological molecules Chemical evolution was rst suggested by a Russian biochemist, Aleksandr Oparin Oparin s Hypothesis (1924): biological evolution was preceded by chemical evolution, i.e., the rst biological molecules were produced from non- living matter [volcanic gases of the second atmosphere] before life began Then biomolecules somehow came together to produce living matter Chemistry 83 Class09 2 Formation of Earth Oldest recorded fossils 4.5-4.8 B 3.3 B 1.2 -1.5 B Evolution of biological chemicals When did chemical evolution occur? Years Ago What are the chemical characteristics of biological molecules? Composition : biomolecules frequently involve the more abundant elements of C, H, N, O, P, and S Size : biomolecules are frequently large (MW > 10000 u) and have large carbon frameworks C uniquely forms strong bonds with all the above elements including itself C always requires 4 bonds to get to inert gas structure and the bonds may be single, double, or triple Structure of C compounds may be chains or rings Chemistry 83 Class09 3 C n H 2n+2 n = 60-100 C n H 2n C n H 2n-2 C n H 2n C 6 H 6 Hydrocarbons are compounds containing only C and H How can large molecules be represented by simplifed structural Formulas? Large molecules make it necessary to replace Lewis structures with simpler representations Condensed structural formulas : represent individual C-H bonds collectively with subscripts Bond line formulas : bonds are represented as lines, C atoms, H atoms and C-H bonds are omitted, but bonds to other atoms as well as all other atoms are shown Chemistry 83...
View Full Document

This note was uploaded on 10/19/2011 for the course CHEM 83 taught by Professor Bonk,j during the Fall '08 term at Duke.

Page1 / 12

Class09 - Chemistry 83 Class09 1 Chemical Evolution From...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online