Key Concepts of Macromolecules in Biology to Know for General Biology I

Macromolecules are the building blocks of life, essential for energy, structure, and function in all living organisms. This includes carbohydrates, lipids, proteins, and nucleic acids, each playing unique roles in biological processes and cellular activities.

1. Carbohydrates

   • Composed of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio.
   • Serve as a primary energy source for living organisms (e.g., glucose).
   • Can be classified into monosaccharides (simple sugars), disaccharides (two sugars), and polysaccharides (many sugars).
   • Play key roles in cell structure and signaling (e.g., cellulose in plants, glycoproteins in cell membranes).
   • Important for energy storage (e.g., starch in plants, glycogen in animals).

2. Lipids

   • Hydrophobic molecules that include fats, oils, waxes, and steroids.
   • Function primarily in energy storage, insulation, and forming cell membranes (phospholipids).
   • Saturated fats (single bonds) vs. unsaturated fats (double bonds) affect fluidity and health impacts.
   • Steroids, such as cholesterol, are vital for hormone production and membrane structure.
   • Lipids play a role in signaling pathways and cellular communication.

3. Proteins

   • Composed of amino acids linked by peptide bonds, forming complex structures.
   • Serve as enzymes, catalysts for biochemical reactions, and are crucial for metabolism.
   • Structure determines function; proteins can be fibrous (structural) or globular (functional).
   • Involved in transport (e.g., hemoglobin), immune response (e.g., antibodies), and muscle contraction.
   • Proteins are essential for cellular structure, signaling, and regulation of biological processes.

4. Nucleic acids

   • Composed of nucleotides, which include a sugar, phosphate group, and nitrogenous base.
   • DNA (deoxyribonucleic acid) stores genetic information; RNA (ribonucleic acid) plays roles in protein synthesis.
   • The sequence of nucleotides encodes genetic instructions for the development and functioning of organisms.
   • RNA types include mRNA (messenger), tRNA (transfer), and rRNA (ribosomal), each with specific functions.
   • Nucleic acids are critical for heredity, gene expression, and the regulation of cellular activities.