Organic Compound
Table of Contents
Organic compounds are chemical compounds that contain carbon (C) atoms, usually bonded to hydrogen (H), and often to other elements such as oxygen (O), nitrogen (N), sulfur (S), phosphorus (P), and halogens (like chlorine (Cl) and fluorine (F)). They are called “organic” because they were once thought to come only from living organisms. Today, we know that organic compounds can also be synthesized in laboratories. [1-4]
Most organic compounds are made up of covalent bonds, where atoms share electrons to achieve stability. Carbon is the central element in organic chemistry because it can form four covalent bonds. This capability allows carbon to create a wide variety of complex structures, including straight chains, branched chains, and rings.
Unique Properties of Carbon [1-6]
1. Tetravalency: Carbon has four valence electrons and can form four covalent bonds with other atoms. This property allows carbon to bond with elements such as hydrogen, oxygen, nitrogen, and others.
2. Catenation: Carbon can bond with other carbon atoms to form long chains or rings. This self-linking property, strongest in carbon compared to other elements, is known as catenation.
3. Multiple Bonding: Carbon atoms can form single, double, or triple bonds. It adds to the variety and complexity of organic compounds.
4. Structural Diversity: Carbon compounds can take on many shapes—linear, branched, or cyclic—leading to millions of possible organic molecules.
General Properties of Organic Compounds [1-6]
1. Low Melting and Boiling Points
Most organic compounds melt and boil at relatively low temperatures due to weak intermolecular forces. At room temperature, many exist as liquids or gases.
Example: Ethanol boils at 78°C.
2. Poor Electrical Conductivity
Organic compounds generally do not conduct electricity in solid or liquid form. They lack free-moving charged particles like ions.
3. Solubility
These compounds dissolve better in non-polar or slightly polar solvents (like ether or benzene) than in water. Compounds with polar groups such as –OH or –COOH may be partially soluble in water due to hydrogen bonding.
4. Combustibility
Organic compounds are usually flammable and burn in air to form carbon dioxide and water. This property makes them valuable as fuels.
Example: Hydrocarbons in gasoline are used in vehicles and engines.
5. Slow Reaction Rates
Many organic reactions are slow and may require heat, light, or catalysts. It is because the molecules are large and the covalent bonds are strong and stable.
Types of Organic Compounds
Organic compounds are the building blocks of life. Four major classes—carbohydrates, lipids, proteins, and nucleic acids—are especially important for the structure and function of cells. [1-6]
1. Carbohydrates
Carbohydrates are composed of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio. They are a primary energy source for living organisms and are found in foods like bread, rice, fruits, and vegetables.
Examples of Carbohydrates
| Type | Name | Formula | Use |
|---|---|---|---|
| Monosaccharide | Glucose | C6H12O6 | Main fuel for cellular respiration |
| Monosaccharide | Fructose | C6H12O6 | Natural sweetener in fruits |
| Disaccharide | Sucrose | C12H22O11 | Table sugar, used in food and drinks |
| Disaccharide | Lactose | C12H22O11 | Found in milk and dairy products |
| Polysaccharide | Starch | (C6H10O5)n | Thickener and energy source in plants |
| Polysaccharide | Glycogen | (C6H10O5)n | Energy storage in animals (liver, muscles) |
| Polysaccharide | Cellulose | (C6H10O5)n | Structural component in plants (wood, paper) |
2. Lipids
Lipids are hydrophobic organic compounds mostly made of carbon and hydrogen, with some oxygen. Unlike carbohydrates, lipids are not built from repeating monomers. Most are formed from glycerol and fatty acids. They serve as long-term energy storage, insulation, and make up cell membranes.
Examples of Lipids
| Type | Example | Structure | Use |
|---|---|---|---|
| Triglyceride | Butter, olive oil | Glycerol + 3 fatty acids | Stores unused energy in fat cells |
| Phospholipid | Glycerophospholipids | Glycerol + 2 fatty acids + phosphate group | Forms cell membranes and supports cell function |
| Steroid | Cholesterol, hormones | Four fused carbon rings | Hormone signaling and membrane fluidity |
3. Proteins
Proteins are complex organic molecules made from chains of amino acids linked by peptide bonds. They include elements such as carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. The specific sequence and shape of a protein determine its function in the body.
Examples of Essential Proteins
| Protein | Example Location | General Function |
|---|---|---|
| Keratin | Hair, nails | Provides strength and structure |
| Amylase | Saliva | Breaks down starch during digestion |
| Hemoglobin | Red blood cells | Carries oxygen throughout the body |
| Antibodies | Immune system | Defends against pathogens |
| Insulin | Pancreas | Regulates blood sugar levels |
4. Nucleic Acids
Nucleic acids store and transfer genetic information. They are composed of nucleotides, each containing a sugar, a phosphate group, and a nitrogen base. These molecules are essential for inheritance and protein synthesis.
Types of Nucleic Acids
| Type | Found In | General Function |
|---|---|---|
| DNA | Chromosomes | Stores hereditary information; controls cell functions |
| RNA | Nucleus, cytoplasm | Helps synthesize proteins from DNA instructions |
In conclusion, the four main types of organic compounds—carbohydrates, lipids, proteins, and nucleic acids—play vital roles in all living organisms. From providing energy and forming cell structures to storing genetic information, these compounds form the chemical basis of life and are essential for growth, function, and reproduction.
