Overview
All living organisms are composed of molecules that interact in highly organized ways to sustain life. Molecular biology studies the chemical building blocks of life and the molecular processes that support cellular functions. Understanding these foundations is key to exploring biology at all levels—from DNA to ecosystems.
Key Concepts and Structures
- Atoms and Molecules: Life is built on carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHONPS).
- Covalent and Ionic Bonds: Covalent bonds share electrons; ionic bonds involve electron transfer.
- Water: Polarity, hydrogen bonding, cohesion, adhesion, and its role as a solvent make water vital for life.
- Organic Molecules:
- Carbohydrates: Sugars and starches—energy and structural roles.
- Lipids: Fats, oils, phospholipids—membrane structure and energy storage.
- Proteins: Made of amino acids—enzymes, structure, communication.
- Nucleic Acids: DNA and RNA—store and transmit genetic information.
Origin of Life and Macromolecules
Early Earth chemistry likely gave rise to organic molecules via energy sources like lightning and UV radiation. These molecules accumulated and eventually organized into simple cells. Proteins and nucleic acids became key in forming self-replicating systems—critical to life’s emergence.
Quick Tip
Focus on how structure relates to function: proteins fold into specific shapes to act as enzymes; phospholipids form membranes due to their hydrophobic tails and hydrophilic heads. Understanding chemistry makes biology clearer.