Essential Organic Molecules: Carbohydrates, Lipids, Proteins, and Nucleic Acids

Organic Molecules: The Building Blocks of Life

The ability of carbon to form long chains gives rise to a variety of molecules, including essential organic compounds.

1. Carbohydrates

Also known as sugars or saccharides, these molecules consist of carbon, hydrogen, and oxygen. Examples include glucose, lactose, and starch. During combustion, carbohydrates provide significant heat and release water and carbon dioxide. Energy is released slowly through progressive oxidations.

2. Lipids

Lipids are generally insoluble in water and have low density. Their primary functions include:

• Energetic: Provide more energy than carbohydrates.
• Reserve: Stored in adipose tissue.
• Structural: Form cell membranes.
• Protection: Shield against external agents and mechanical impact.
• Transportation: Carry fats through the bloodstream.
• Biocatalyst: Facilitate metabolic reactions.
• Insulation: Insulate nerve impulses (e.g., myelin).

Classification of Fats

• Saturated Fats: Animal or vegetable origin; the liver uses them to manufacture cholesterol.
• Monounsaturated Fats: Do not alter cholesterol levels.
• Polyunsaturated Fats: Beneficial for bone development and the immune system.

3. Proteins

Proteins are large molecules formed by the union of amino acids. They are composed of carbon, oxygen, hydrogen, and nitrogen, often including phosphorus or sulfur. Their key functions include:

1. Enzymatic: Regulate chemical reactions essential for life.
2. Structural: Essential for building and repairing cells.
3. Transportation: Hemoglobin transports oxygen in the blood.
4. Hormonal: Hormones like insulin control blood glucose levels.
5. Defense: Antibodies defend the body against microbial invasion.
6. Nutritive: Act as food reserves, such as egg albumen.

4. Nucleic Acids

These molecules are composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus. There are two primary types:

• DNA (Deoxyribonucleic Acid): Organizes all cell activity and carries genetic material passed to offspring.
• RNA (Ribonucleic Acid): Originates from DNA and is involved in protein synthesis.