Chapter 3: Introduction to Organic Compounds

Organic compounds

molecules primarily composed of carbon atoms bonded with other elements, especially hydrogen, oxygen, and nitrogen.

Life’s molecular diversity

 based on the versatility of carbon.

How many carbon atoms does it take to form covalent bonds?

Carbon atoms can form four covalent bonds, allowing for a wide variety of stable and complex molecules.

Carbon chains

form the backbone of most organic molecules.

Isomers

are compounds with the same molecular formula but different structures, resulting in different properties.

Hydrocarbons

 are composed only of carbon and hydrogen atoms.

Chains

Vary in length (e.g., methane, ethane, propane).

Double bonds

Carbon skeletons may have double bonds, which can vary in location (e.g., 1-butene, 2-butene).

Branching

Skeletons can be unbranched (butane) or branched (isobutane).

Rings

Carbon skeletons may form rings (e.g., cyclohexane, benzene).

Functional Group

The properties of organic molecules are influenced by the presence of specific groups of atoms called functional groups. These groups confer specific chemical properties and reactivity to the molecules. Functional groups are often hydrophilic, increasing the solubility of organic compounds in water. Six important functional groups are commonly found in biological molecules.

Hydroxyl

–OH

Alcohols (e.g., ethanol)

Polar, forms hydrogen bonds

Carbonyl

–C=O

Aldehydes, ketones

Polar, found in sugars

Carboxyl

–COOH

Carboxylic acids (e.g., acetic acid)

Acidic, donates H+

Amino

–NH2

Amines (e.g., glycine)

Basic, accepts H+

Phosphate

–OPO32–

Organic phosphates (e.g., ATP)

Contributes negative charge, energy transfer

Methyl

–CH3

Methylated compounds

Nonpolar, affects gene expression