Biochemistry Overview and Biomolecules

Introduction to Biochemistry

• Biochemistry is the study of chemical processes within and relating to living organisms.
• It encompasses the structure, function, and interaction of biomolecules like proteins, carbohydrates, lipids, and nucleic acids.
• It overlaps significantly with other disciplines such as molecular biology, genetics, and physiology.
• Understanding biochemistry is crucial for comprehending life processes and developing treatments for diseases.

Biomolecules: Structure and Function

• Proteins: Complex polymers of amino acids.
  • Perform a vast array of functions, including catalysis (enzymes), transport, signaling, and structural support.
  • Their structure is crucial to their function. The primary structure (amino acid sequence) dictates the secondary (e.g., alpha-helices, beta-sheets), tertiary (overall 3D shape), and quaternary (multiple polypeptide chains interacting) structures.
  • Protein folding determines its activity.
• Carbohydrates: Include monosaccharides, disaccharides, and polysaccharides.
  • Serve as a primary energy source and structural components (e.g., cellulose).
  • Bonds between monosaccharides form disaccharides and polysaccharides such as starch and glycogen, which are important for energy storage.
• Lipids: Diverse group of hydrophobic molecules.
  • Include fats, phospholipids, and steroids.
  • Important for energy storage, membrane structure, hormone production, and insulation.
  • Phospholipids are crucial components of cell membranes.
• Nucleic Acids: DNA and RNA.
  • Carry genetic information.
  • DNA (deoxyribonucleic acid) stores the genetic code, and RNA (ribonucleic acid) plays crucial roles in protein synthesis, gene regulation and other cellular processes.
  • Their structure involves nucleotides, which are linked to form polynucleotide chains.

Metabolism

• Metabolism encompasses all chemical reactions in a cell.
• Catabolism: Breakdown of complex molecules to release energy.
  • Key pathways include glycolysis, the Krebs cycle, and oxidative phosphorylation.
• Anabolism: Synthesis of complex molecules from simpler ones, utilizing energy.
  • Examples include protein synthesis, glycogen synthesis, and lipid synthesis.
• Cellular Respiration: Metabolic process that releases energy from glucose in the presence of oxygen.

Enzymes

• Enzymes are biological catalysts that speed up the rate of chemical reactions.
• They act by lowering the activation energy.
• Enzymes are highly specific, typically catalyzing only one type of reaction.
• Their active sites bind with substrates and catalyze reactions.

pH and Buffers

• pH is a measure of hydrogen ion concentration.
• Enzymes and other biomolecules function optimally within a narrow pH range.
• Buffers help maintain a stable pH by resisting changes in hydrogen ion concentration.
• Understanding and controlling pH is critical to most biochemical processes.

Water

• Water is the universal solvent of life.
• Its unique properties (polarity, hydrogen bonding) enable it to dissolve many substances.
• Water's high heat capacity and heat of vaporization are crucial for thermoregulation in living organisms.

Thermodynamics

• Biochemical reactions follow the laws of thermodynamics.
• Understanding free energy changes and equilibrium constants is crucial in predicting the spontaneity and feasibility of biochemical reactions.

Redox Reactions

• Redox reactions involve the transfer of electrons.
• Crucial in metabolic processes such as cellular respiration.
• Co-enzymes frequently participate in electron transfer, including NAD+ and FAD.

Introduction to Bioenergetics

• Study of energy flow within living things.
• Energy is stored and released in chemical bonds of biomolecules.
• Understand the energy currency of the cell, ATP (adenosine triphosphate).