Properties of Organic Compounds

A. The molecules of life are organic compounds, meaning that they consist of atoms of carbon and one or more other elements, held together by covalent bonds.

B. Effects of Carbon's Bonding Behavior

1. Living organisms are mostly oxygen, hydrogen, and carbon.

2. Much of the hydrogen and oxygen are linked as water.

3. Carbon can form four covalent bonds with other atoms to form organic molecules of several configurations.

C. Hydrocarbons and Functional Groups

1. A hydrocarbon has only hydrogen atoms attached to a carbon backbone.

2. Functional groups, atoms or groups of atoms covalently bonded to a carbon backbone, convey distinct properties, such as solubility, to the complete molecule.

D. How Cells Use Organic Compounds—Five Classes of Reactions

1. Enzymes speed up specific metabolic reactions.

2. There are five types of reactions in which biological molecules participate:

a. Functional-group transfer: one molecule donates, another accepts.

b. Electron transfer: one or more electrons are removed and donated.

c. Rearrangement: internal bonds are rearranged converting one type of organic molecule to another.

d. Condensation: through covalent bonding, two molecules combine to form a larger molecule.

e. Cleavage: a molecule splits into two smaller molecules.

E. Condensation and Hydrolysis Reactions

1. In condensation (also called dehydration synthesis), one molecule is stripped of its H+; another is stripped of its OH–. The two molecule fragments join to form a new compound, and the H+ and OH form water (dehydration synthesis).

2. Hydrolysis is the reverse: one molecule is split by the addition of H+ and OH (from water) to the components.

3. Monomers can join to form polymers, and vice versa.

F. The Molecules of Life

1. These include simple sugars, fatty acids, amino acids, and nucleotides.

2. They are used as an energy source or as building blocks for the synthesis of macromolecules: polysaccharides, lipids, proteins, and nucleic acids.

Organic compounds: Built on carbon atoms

    The Chemistry of Carbon : Text and 3D models created by the Academic Computing Facility at New York University. You'll need to download a 3-D viewer to get the full effect.

    Functional Groups : A chart of the most common functional groups.

    Introduction to Organic Nomenclature : Visit this site to learn how carbon-containing compounds are named. To view the 3D images of the compounds you'll need to follow the instructions on the first page and obtain the appropriate plug-in for your browser.

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