1. Organic Molecules
Section 3.1

2. Learning Objectives
Describe the properties of carbon that make it the central component of organic compounds
Define the term isomer and explain why they have different properties
Identify the major functional groups found in organic compounds & describe their properties
Explain the relationship between polymers & macromolecules

3. Organic vs. Inorganic
All carbon compounds can be classified into 2 large categories:
Organic Compounds = carbon atoms are covalently bonded to each other to form the backbone of the molecule
Examples: Proteins, DNA, Sugars, Fats
Inorganic Compounds = Carbon is not bonded to another carbon or hydrogen
Example: Carbon dioxide (CO2)
Also includes molecules with no carbon
Examples: Ammonium (NH4+) and Nitrate (NO3-)

4. Carbon is Found in Many Molecules
Carbon atoms have four valence electrons (outer electrons)
Can form 4 covalent bonds with other atoms

5. The 4 single bonds of carbon point to the corners of a tetrahedron.
Properties of Carbon
It can join with other carbon atoms to make chains or rings
Carbon to carbon bonds are strong & not easily broken
Structural formula
Ball-and-stick model
Space-filling model
Methane
The 4 single bonds of carbon point to the corners of a tetrahedron.
Figure 3.1, top part
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

6. Carbon skeletons vary in many ways

7. Hydrocarbons
Hydrocarbons = organic molecules containing only carbon and hydrogen atoms
Simplest organic compounds
Are nonpolar
Vary in length (long or short) and arrangement (branched or unbranched)
Carbon skeleton = the chain of carbon atoms in an organic molecule

8. Structure Influences Function
A molecule’s structure determines its function
Same molecular formula doesn’t always mean same structure
Isomers = compounds with the same molecular formula but with different structures & properties

9. Functional groups change the properties of organic molecules
Functional group = a group of atoms that participate in chemical reactions
Are hydrophilic (water loving)
A molecule without a functional group is said to have a methyl group
Don’t copy the next slide in your notes if you put slide 11 in your diagram page!

10. Methyl group – carbon bonded to 3 hydrogen
Hydroxyl group – hydrogen bonded to an oxygen
Common in alcohols and sugars
Carbonyl group – carbon double-bonded to an oxygen
Can be an aldehyde (O bonded to end C) or a ketone (O bonded to an interior C)
Carboxyl group – carbon double-bonded to an oxygen and a hydroxyl group
Amino group – nitrogen bonded to 2 hydrogen
Phosphate group – phosphorus atom bonded to 4 oxygen
Sulfhydryl group – sulfur bonded to a hydrogen

12. Large Biological Molecules Are Made Up of Smaller Molecules
Macromolecule = a very large molecule (ex. Lipid, protein, nucleic acid, and carbohydrate)
Most macromolecules are polymers
Polymer = a large molecule built from smaller molecules called monomers
Monomer = a molecule that can be joined together to make a polymer
A huge number of different polymers can be made from a small number of monomers

14. Building Macromolecules
Condensation reaction = links monomers together to build a polymer
Also called dehydration synthesis or dehydration reaction
OH of one monomer bonds with H of second monomer to create water
Water leaves & the two monomers are joined together

16. Breaking Down Macromolecules
Hydrolysis reaction = breaks down polymers into monomers
Water is added
OH joins one side of the bond & H joins the other side, breaking the monomers apart