Types of Biological Molecules to Know for Biology for Non-STEM Majors

Biological molecules are the building blocks of life, playing key roles in energy, structure, and function. Understanding carbohydrates, lipids, proteins, nucleic acids, and water helps us grasp how living organisms operate and interact with their environment.

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 simple sugars (monosaccharides) and complex carbohydrates (polysaccharides).
   • Play a crucial role in cell structure and signaling (e.g., cellulose in plants, glycoproteins).
   • Important for energy storage (e.g., starch in plants, glycogen in animals).

2. Lipids

   • Hydrophobic molecules that include fats, oils, waxes, and steroids.
   • Serve as long-term energy storage and insulation for organisms.
   • Form essential components of cell membranes (phospholipids).
   • Play roles in signaling (e.g., hormones like testosterone and estrogen).
   • Important for absorbing fat-soluble vitamins (A, D, E, K).

3. Proteins

   • Made up of amino acids linked by peptide bonds, forming complex structures.
   • Serve as enzymes, catalysts that speed up biochemical reactions.
   • Play critical roles in structure (e.g., collagen in connective tissues) and transport (e.g., hemoglobin in blood).
   • Involved in immune responses (e.g., antibodies) and cell signaling (e.g., receptors).
   • The sequence and structure of amino acids determine protein function and specificity.

4. Nucleic acids

   • Composed of nucleotides, which include a sugar, phosphate group, and nitrogenous base.
   • DNA (deoxyribonucleic acid) stores genetic information, while RNA (ribonucleic acid) plays a role in protein synthesis.
   • Essential for heredity and the transmission of genetic information across generations.
   • RNA types include mRNA (messenger), tRNA (transfer), and rRNA (ribosomal), each with specific functions.
   • Nucleic acids are vital for cellular processes, including replication, transcription, and translation.

5. Water

   • A polar molecule essential for life, making up a significant portion of living organisms.
   • Acts as a solvent, facilitating biochemical reactions and transport of substances.
   • Regulates temperature and maintains homeostasis through its high specific heat capacity.
   • Participates in hydrolysis and dehydration synthesis reactions, crucial for metabolism.
   • Provides structure and support in cells (e.g., turgor pressure in plant cells).