C ARBON AS A B ASIS FOR L IFE Chapter 4

T HE I MPORTANCE OF C ARBON All living organisms based significantly on carbon Creates a large diversity of biological molecules Includes: proteins, DNA, carbohydrates, lipids, and others Distinguishes living form nonliving matter All these molecules are examples of emergent properties

D EFINING O RGANIC C HEMISTRY Organic compounds are anything containing carbon Hydrocarbon molecules contain only hydrogen and carbon Simple (CH 4 ) to large and diverse (proteins) Organic molecule variation exists both w/i individual species and b/w different species The four main elements of living organisms are? (hint: 96% of the human body) Valence is the number of covalent bonds an atom can make Valence electrons are ALL electrons in outermost shell

C ARBON ’ S A BILITY TO B OND 6 electrons, ? in first shell and ? in outer shell Can donate or accept electrons equally (form an ion) Usually shares (covalent bonds) Single, double, or triple Makes large, complex molecules possible Each line between 2 atoms represents 2 shared electrons

C ARBON C ARBON B ONDING Skeletons of most organic compounds are carbon chains Straight, branched, or ringed Number and bond type vary Examples of hydrocarbons

H YDROCARBONS What constitutes a hydrocarbon? Main components of fossil fuels b/c come from decomposed living organisms Not major component of living organisms, but are regions in other molecules Reactions cause large amounts of energy release Fats – long, nonpolar, hydrophobic tail Serve as stored fuel in animals Used in gasoline

I SOMERS 2 molecules with the same # of the same atoms, but different structure = different properties 3 types Structural Covalently bonded and arranged in different orders Number of configurations increase with increase in number of carbons Geometric Covalently the same partners, but different spatial arrangement Double bonds prohibit rotation Enantiomer Mirror images (R- and L-) Usually one is inactive Important in pharmaceuticals because both can have different effects

I SOMER E XAMPLES Geometric Isomer Enantiomer Structural Isomer 4C’s and 8H’s 1 of each 2C’s, 2H’s, and 2 Cl’s Cl

B IOMOLECULAR F UNCTIONING Hydrogens can be replaced by other atom groupings Arrangement determines properties May participate directly in reactions or indirectly because of shape Sex hormones as an example Testosterone vs estradiol Different actions Minimal differences in structure

F UNCTIONAL G ROUPS

A DENOSINE T RIPHOSPHATE (ATP)  Addition of water removes 1 phosphate to create ADP  HOPO 3 2- abbreviated as P i  ATP ‘stores potential to react with water’  ATP + water releases Energy for cell use Addition of water