Introduction to Biochemistry

Introduction to Biochemistry

• Biochemistry is the study of chemical processes within and relating to living organisms.
• It encompasses a wide range of topics, from the structure and function of biological molecules to the metabolic pathways that drive life.
• This includes understanding how molecules like proteins, carbohydrates, lipids, and nucleic acids interact and function in cells and organisms.
• It focuses on the chemical transformations that occur within living systems.

Biological Molecules

• Carbohydrates: These are crucial for energy storage and structural support.
  • Simple sugars (monosaccharides) like glucose and fructose serve as immediate fuel sources.
  • Complex carbohydrates (polysaccharides) such as starch and glycogen store energy.
  • Cellulose provides structural support in plant cell walls.
• Lipids: These are diverse molecules with roles in energy storage, insulation, and membrane structure.
  • Fats and oils are primary energy storage forms.
  • Phospholipids are essential components of cell membranes, forming a bilayer.
  • Steroids like cholesterol are crucial for hormone production and membrane fluidity.
• Proteins: Complex organic molecules composed of amino acids.
  • They perform a vast array of functions, from catalysis (enzymes) to transport, structure, and signaling.
  • Protein structure is crucial to function; it can be primary, secondary, tertiary, or quaternary.
• Nucleic Acids: These carry genetic information and control protein synthesis.
  • DNA (deoxyribonucleic acid) stores genetic instructions.
  • RNA (ribonucleic acid) plays a vital role in protein synthesis and other cellular processes.

Enzymes

• Enzymes are biological catalysts; they speed up reactions without being consumed.
• They are typically proteins.
• The active site on an enzyme interacts with a substrate to catalyze a specific reaction.
• Enzyme activity is affected by factors like temperature and pH.

Metabolism

• Metabolism refers to 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 input.
• Metabolic pathways are sequences of enzyme-catalyzed reactions converting substrates to products.
  • These pathways have various control mechanisms to regulate their activity, crucial for maintaining homeostasis.

Cellular Respiration

• Cellular respiration is the process by which cells break down glucose to produce ATP (adenosine triphosphate), the cell's energy currency.
• It has three main stages: glycolysis, the Krebs cycle, and oxidative phosphorylation.
• Each stage generates ATP through different mechanisms.

Photosynthesis

• Photosynthesis is the process by which plants and other organisms convert light energy into chemical energy in the form of glucose.
• It requires chlorophyll, a pigment that absorbs light energy.
• The process occurs in chloroplasts.
• Two main stages are involved: the light-dependent reactions and the light-independent reactions (Calvin cycle).

Acid-Base Balance

• Maintaining a stable pH is critical for cellular function.
• Buffers are vital for preventing drastic changes in pH.
• The human body has systems to regulate pH, including the respiratory and renal systems.

Water

• Water is an essential molecule in biochemistry, playing a critical role in various biological processes.
• Its polarity and hydrogen bonding properties are crucial for many biological functions.
• Water participates in hydrolysis and dehydration reactions that are fundamental to metabolic processes.

pH and Buffers

• pH measures the acidity or basicity of a solution.
• Buffers resist changes in pH.
• Many biological systems have buffering systems to maintain a stable pH.

Redox Reactions

• Redox reactions (oxidation-reduction) involve the transfer of electrons between molecules.
• They play a crucial role in metabolism, including photosynthesis and cellular respiration.

Macromolecular Structure

• Macromolecules like proteins, nucleic acids, and polysaccharides have hierarchical structures: Primary, secondary, tertiary, and quaternary.
• Understanding these structures helps in deciphering their biological functions.
• The structure of these molecules directly impacts how they perform their roles, for example, an enzyme's active site formation.