Introduction to Biochemistry

Introduction to Biochemistry

• Biochemistry is the study of chemical processes within and relating to living organisms.
• It encompasses a broad range of topics, including the construction and function of biological molecules, metabolism, and regulating biochemical processes.
• It is directly linked to other biological disciplines such as molecular biology, genetics, and physiology.
• Understanding biochemical processes is vital for deciphering the mechanisms of life and developing novel approaches to treating diseases.

Biological Molecules

• Carbohydrates: Include sugars, starches, and cellulose. They are a primary energy supply and structural components.
  • Simple sugars (monosaccharides) are the fundamental structural units.
  • Complex carbohydrates (polysaccharides) are formed by linking monosaccharides.
• Lipids: Include fats, oils, and steroids. These are essential for energy storage, insulation, and membrane structure.
  • Fatty acids are a crucial component of lipids.
  • Phospholipids are the foundation of cell membranes.
  • Steroids have various functions, including hormone production.
• Proteins: Complex molecules composed of amino acids. They play a critical role in structure, catalysis, transportation, and regulation.
  • Amino acids are connected by peptide bonds to form polypeptide chains.
  • Proteins have specific three-dimensional structures that define their functions.
• Nucleic Acids: Include DNA and RNA. They carry genetic information and direct protein synthesis.
  • DNA (deoxyribonucleic acid) stores genetic information.
  • RNA (ribonucleic acid) plays a role in protein synthesis and other cellular processes.

Metabolism

• Metabolism encompasses all the chemical reactions occurring within a living organism.
• Catabolism breaks down complex molecules into simpler ones, releasing energy.
• Anabolism builds complex molecules from simpler ones, requiring energy.
• Cellular Respiration: A catabolic process that releases energy from glucose in the presence of oxygen, producing ATP (adenosine triphosphate).
• Photosynthesis: An anabolic process in plants that transforms light energy into chemical energy (glucose).

Enzymes

• Enzymes are biological catalysts that accelerate biochemical reactions.
• They are usually proteins with specific three-dimensional shapes.
• Enzymes lower the activation energy required for a reaction to occur.
• Enzymes are highly specific, facilitating only certain reactions.
• Enzyme activity is influenced by factors like temperature and pH.

Cellular Respiration in Detail

• Glycolysis: Breakdown of glucose into pyruvate, producing a small amount of ATP.
• Krebs Cycle (Citric Acid Cycle): Further breakdown of pyruvate, generating more ATP and electron carriers (NADH, FADH2).
• Electron Transport Chain (Oxidative Phosphorylation): Electrons from NADH and FADH2 are transported along a chain, producing a significant amount of ATP through chemiosmosis.

Photosynthesis in Detail

• Light-dependent reactions: Capture light energy to generate ATP and NADPH.
• Light-independent reactions (Calvin cycle): Use ATP and NADPH to convert CO2 into glucose.

Regulation of Biochemical Processes

• Feedback inhibition: The final product of a metabolic pathway inhibits an enzyme earlier in the pathway, controlling the process.
• Allosteric regulation: Molecules bind to specific sites on enzymes, changing their shape and activity.
• Hormonal regulation: Hormones manage metabolic processes by signaling pathways.

Importance of Biochemistry

• Understanding fundamental biological processes.
• Developing new diagnostic and therapeutic approaches.
• Designing novel biomaterials.
• Manipulating metabolic pathways.
• Improving agricultural practices.