An Overview of Organic Compounds: Carbohydrates and Lipids

Fundamental Concepts of Organic Compounds

Organic compounds are primarily carbon-based, utilizing carbon's versatility to form four covalent bonds. These compounds are often polymers, long chains made of smaller building blocks called monomers. Polymers are synthesized through dehydration synthesis—a process that removes water to link monomers—and are broken down into monomers via hydrolysis, which uses water to cut the molecular bonds.

Carbohydrates: Sugars and Starches

Carbohydrates, composed of carbon, hydrogen, and oxygen, function as essential fuel and provide structural components. They are classified by the number of monomers: monosaccharides (one, such as glucose or ribose), disaccharides (two, such as sucrose or lactose), and polysaccharides (many, such as starch or glycogen). Disaccharides and polysaccharides are created through dehydration synthesis.

Lipids: Structure and Function

Lipids are nonpolar, hydrophobic compounds containing carbon, hydrogen, and oxygen. The primary types include triglycerides (used for energy storage and insulation), phospholipids (essential for cell membranes), steroids (four-ring structures including cholesterol and hormones), and eicosanoids. Triglycerides consist of three fatty acid chains attached to a glycerol molecule, categorized as saturated (single bonds, solid) or unsaturated (double bonds, liquid/kinks).

Specialized Lipids and Transport

Phospholipids are unique due to their amphipathic nature, possessing a polar hydrophilic head and nonpolar hydrophobic tails, allowing them to form the cell membrane bilayer. Because lipids cannot dissolve in water, the body uses lipoproteins to transport them through the bloodstream. Additionally, fat-soluble vitamins (A, D, E, and K) are categorized under lipids.