Introduction to Biochemistry

Introduction to Biochemistry

• Biochemistry is the study of the chemical processes within and relating to living organisms.
• It focuses on the structure, function, and interactions of biological macromolecules.
• These macromolecules include proteins, carbohydrates, lipids, and nucleic acids.
• It examines the processes of metabolism, including catabolism (breakdown) and anabolism (synthesis).
• Biochemistry overlaps significantly with other biological disciplines, including genetics, molecular biology, and cell biology.

Biological Macromolecules

• Proteins:
  • Composed of amino acids linked by peptide bonds.
  • Exhibit a wide range of functions, including catalysis (enzymes), transport, structure, and defense.
  • Structure is crucial to function; primary, secondary, tertiary, and quaternary structures are key concepts.
  • Denaturation can disrupt protein structure and function.
• Carbohydrates:
  • Primarily composed of carbon, hydrogen, and oxygen.
  • Source of energy and structural components.
  • Include monosaccharides (simple sugars), disaccharides, and polysaccharides (complex carbohydrates).
  • Starch, glycogen, and cellulose are examples of polysaccharides with different functions.
• Lipids:
  • Hydrophobic molecules, insoluble in water.
  • Include fats, oils, phospholipids, and steroids.
  • Important for energy storage, membrane structure, and hormone production.
  • Fatty acids, triglycerides, and phospholipids are crucial lipid types.
• Nucleic Acids:
  • DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
  • Carry genetic information.
  • Composed of nucleotides, each containing a base (adenine, guanine, cytosine, thymine, or uracil), a sugar (deoxyribose or ribose), and a phosphate group.
  • DNA's double helix structure is essential for its function.

Metabolism

• Catabolism:
  • Breakdown of complex molecules into simpler ones, releasing energy.
  • Examples include glycolysis, the citric acid cycle, and oxidative phosphorylation.
• Anabolism:
  • Synthesis of complex molecules from simpler ones, requiring energy.
  • Examples include protein synthesis and the synthesis of complex carbohydrates.
  • These processes are often linked via energy carriers like ATP (adenosine triphosphate).

Enzymes

• Biological catalysts that speed up chemical reactions in living organisms.
• Highly specific for their substrates.
• Activity is affected by factors such as temperature, pH, and concentration of substrates and inhibitors.
• Function by lowering the activation energy of reactions.
• Following the lock and key or induced fit models to explain interactions with substrates.

Water

• Essential for life, with unique properties crucial for biochemical processes.
• High specific heat and heat of vaporization.
• Acts as a solvent for many polar and ionic substances.
• Crucial for maintaining homeostasis in organisms.
• High surface tension.
• Water plays a key role in enzymatic reactions, transport of molecules, and other essential cell functions.

pH and Buffers

• pH: Measure of hydrogen ion concentration, crucial for many biochemical reactions.
• Buffers: Solutions that resist changes in pH when acids or bases are added.
• Essential for maintaining stable internal environments within living organisms.
• Examples of buffers include bicarbonate and phosphate.

Vitamins and Minerals

• Essential organic molecules, often acting as coenzymes.
• Required in small amounts for various metabolic processes.
• Not synthesized by the body and must be acquired through diet.
• Different types of vitamins have various roles in metabolic pathways.
• Important inorganic elements required in small amounts for vital biological functions.

Cellular Respiration

• Process by which cells break down glucose to produce ATP.
• Includes glycolysis, the citric acid cycle, and oxidative phosphorylation.
• Provides energy for cellular work and function. Important metabolic pathway to understand.

Other Key Concepts in Biochemistry

• Redox Reactions: Reactions involving electron transfer. Critical in energy production and cellular respiration.
• Oxidation and Reduction: Processes involved in redox reactions.
• Allosteric Regulation: Enzymes can be regulated by binding molecules at sites other than the active site.
• Competitive and Non-competitive Inhibition: Types of enzyme inhibition.
• Energy Coupling: The use of energy released from one reaction to drive another. Crucial in cellular processes.
• Activation Energy: The energy required to initiate a chemical reaction.
• Gibbs Free Energy: Measures the amount of usable energy in a system.
• Hydrolysis: Chemical reaction that breaks down a molecule by adding water.
• Dehydration Synthesis: Process that creates a molecule of water when binding molecules.