Carbon & Molecular Diversity Ch 4  Chapter 4

Carbon Overview  Backbone for biological molecules All living organisms are made up of chemicals based mostly on carbon  Organic Molecules Carbs, Lipids, Nucleic Acids, Proteins Include CHNOPS in different combinations in all living things  Enters biosphere through plants (photosynthesis) which covert CO 2 into molecules for life using sunlight energy

Organic Chemistry  The study of compounds containing carbon Must contain carbon and hydrogen CO 2 not organic  Originally thought to only be produced by living things  Herman Kolbe made the organic compound acetic acid from inorganic compounds NH 4 + and CNO -  Stanley Miller (Urey’s student) related it to evolution Chemical origin of life (created organic material from inorganic material Recreated Earth’s early atomosphere, produced amino acids and other small organic molecules

Carbon Bonding H O NC Hydrogen (valence = 1) Oxygen (valence = 6) Nitrogen (valence = 5) Carbon (valence = 4) Figure 4.4

Carbon Bonding  Can form 4 covalent bonds Double or single 4 valence electrons – tetravalence Versatile, varied, and diverse (a) Methane (b) Ethane (c) Ethene (ethylene) Molecular Formula Structural Formula Ball-and- Stick Model Space- Filling Model H H H H H H H H H H HH H H C C C CC CH 4 C2H6C2H6 C2H4C2H4 Name and Comments Figure 4.3 A-C

Carbon Skeletons  Vary in length  Can branch  Can contain double or single bonds  Can be found as rings H H H H H HH H H H H HHH H H H H H H H H H H H H H H H H H H HH H H H HH H HH HH H H H H H H H C C CCC C C CC CC C CCCCCCCC C C C C C C C C C C C C H H H H H H H (a) Length (b) Branching (c) Double bonds (d) Rings Ethane Propane Butane 2-methylpropane (commonly called isobutane) 1-Butene2-Butene Cyclohexane Benzene HH HHH Figure 4.5 A-D

Hydrocarbons (a) A fat molecule (b) Mammalian adipose cells 100 µm Fat droplets (stained red) Figure 4.6 A, B

Hydrocarbons  Contain only carbon and hydrogen, release a lot of energy when the bond is broken  hydrophobic

Isomers  Isomers - molecules with the same molecular formula but different structures and therefore different properties H H HH H H H H HH H H H HH H H H H H H H HH H H H H CO 2 H CH 3 NH 2 C CO 2 H H CH 3 NH 2 XX X X C CCCC C C C C C C C C C C (a) Structural isomers (b) Geometric isomers (c) Enantiomers H Figure 4.7 A-C

Isomers  1. Structural Isomers – differ in the covalent arrangements of their atoms # of possible structural isomers increases as skeletons increase in size

Isomers  2. Geometric Isomers – differ in the arrangement around a double bond Cis – same side Trans – opposite sides

Isomers  Enantiomers – mirror images of each other L (left) and D (right) Asymmetric carbon – 4 different atoms or groups of atoms

Functional Groups

 The parts of molecules involved in chemical reactions  Are the chemically reactive groups of atoms within an organic molecule  Give organic molecules distinctive chemical properties  Six important to life

Functional Groups  1. Hydroxyl - hydrogen bonded to an oxygen bonded to a carbon skeleton  -OH or OH- (NOT hydroxide OH - )  Alcohols Ex: Ethan ol  Polar  Attract water molecules

Functional Groups  2. Carbonyl – carbon joined to an oxygen with a double bond  >C=O  Ketone (middle) or aldehyde (end) Acet one and propan al  Frequently structural isomers

Functional Groups  3. Carboxyl – oxygen is double bonded to a carbon that is also bonded to a hydroxyl  - COOH  Carboxylic Acids Acetic acid  Acidic properties – donates H+ (proton)  Polar  Carboxylate – ionic form in cells (-)

Functional Groups Amino  4. Amino – nitrogen atom bonded to 2 hydrogen atoms and the carbon skeleton  - NH 2  Amines Glyc ine  Basic properties – picks up H+  Ionized in cells (+)

Functional Groups  5. Sulfhydryl – sulfur atom bonded to a hydrogen  -SH or –HS  Thiols ethaneth iol  Groups interact to form disulfide bridges that stabilize proteins

Functional Groups  6. Phosphate – phosphorus is bonded to 4 oxygen atoms 1 oxygen bonds to the carbon 2 oxygens are negative  -OPO 3 2-  Organic Phosphates Adenosine tri phosphate (ATP) reacts with water to produce ENERGY  Transfers energy between organic molecules

Isomers  Create a tree map to classify and describe the different types of isomers. Give an example of each and draw and example of each.  Summarize