BiochemLEC-Summarized.docx

[[Chapter 1. INTRODUCTION]](https://classroom.google.com/u/2/c/NzA4MTc1MjExNDM4/m/NzA5MTQ1MDMwNDg5/details) ----------------------------------------------------------------------------------------------------------------------- **Biochemistry** studies the chemical processes in living organisms, cr...

[[Chapter 1. INTRODUCTION]](https://classroom.google.com/u/2/c/NzA4MTc1MjExNDM4/m/NzA5MTQ1MDMwNDg5/details) ----------------------------------------------------------------------------------------------------------------------- **Biochemistry** studies the chemical processes in living organisms, crucial for understanding digestion, respiration, metabolism, growth, and reproduction. ### **Importance of Biochemistry in Medical Science** \- Every biological function involves chemical reactions. \- Studying one type of protoplasm applies to all. \- Focuses on the chemical composition of cells and their processes. ### **Scope of Biochemistry** 1\. **Composition of living matter** - Chemical processes in the body. 2\. **Biochemistry of tissues** -- Chemical components. 3\. **Foods and vitamins** -- Cellular functions. 4\. **Study of enzyme**s -- Nature and function of biocatalysts. ### **The Chemical Composition of Living Matter** **A. Organic --** contain carbon **Carbohydrates**: Sugars and starches (C, H, O in a 1:2:1 ratio). Mono-, di-, and polysaccharides formed via dehydration synthesis. **Lipids**: Phospholipids, steroids, triglycerides (C, H, O) with C and H outnumbering O, insoluble in water. **Proteins**: Composed of amino acids (C, H, O, N, sometimes S). Fibrous (structural) and globular (functional) types. Denatured by heat or pH changes. **Nucleic Acids**: DNA (genetic material) and RNA (mRNA, tRNA, rRNA for protein synthesis). ATP is a chemical energy molecule. - - - - - - A. **Water** - Major cell component, solvent with high specific heat, surface tension, and solvent properties. ### **General Properties:** Water has unique properties. This is due to the strong intermolecular forces caused by electrical polarity of water. **Water has exceptional solvent properties.** - **Water properties altered by solutes.** - **Water has HIGH Specific Heat.** - **Water has HIGH Latent Heat of Vaporization** - **Water has HIGH Latent Heat of Fusion** - **Water has a HIGH Surface Tension** \- Water has high surface tension, allowing for capillary rise and the concentration of dissolved substances at interfaces. This property is important for biological cell membranes, influencing molecule movement and cell function. **Salt** -- Ionic compounds that dissociate in body fluids, forming electrolytes that conduct electrical currents. **Acid** \- taste sour \- dissolve many metals or burn holes in materials including skin \- proton donors **Base** \- Taste bitter \- feel slippery \- proton acceptors \- ionize and dissociate in water ### **Biochemistry of Tissues** Tissues contain 70%-90% water and 10%-30% solids, with 1% being inorganic and the rest organic. Water in tissues exists in two forms: ### **Foods and Vitamins** - - - - ### **Study of enzymes** \- **Enzymes**: Proteins that act as biological catalysts, accelerating chemical reactions. \- **Substrates**: Molecules enzymes act upon, converting them into products. \- **Enzymology**: The study of enzymes and pseudoenzymes, which have lost catalytic function. \- **Enzyme activity**: Affected by inhibitors (decrease activity) and activators (increase activity). \- **Denaturation**: Enzymes lose function due to excessive heat or pH changes. **- Commercial use**: Enzymes are used in antibiotics, washing powders, and meat tenderizers to break down proteins and stains. ### **Chemical Reactions Occurring in Living Matter** **Oxidation**: Energy is released by the oxidation of organic substances (carbs, fats, proteins). - - **Reduction**: The reverse of oxidation; involves gaining hydrogen or electrons. **Hydrolysis**: Water molecules break down compounds into fragments. **Condensation**: Simple molecules unite to form complex substances (e.g., tissue protein synthesis). **Tautomerism**: Atoms rearrange within a molecule to create a new substance. TOPIC 2 ======= \- **Specialized Cells**: Cells with structures suited to their specific functions. \- **Animal and Plant Cells**: \- Both have unique structures based on their functions and activated genes. **Prokaryotic and Eukaryotic cells** **The Differences Between Prokaryotic and Eukaryotic cells.** **Prokaryotic Cells** **Eukaryotic Cells** ----------------------- ---------------------- Small Large One unit Compartments Simple Complex Efficient Redundant **Parts of a Prokaryotic Cell** **Capsule** \- Promotes bacterial adhesion \- Permeability barrier against phagocytosis. \- Nutrient reserve **Cell Wall** \- Protection \- Structural support \- Maintenance of cell shape **Plasma Membrane** \- Separates cell from the external environment \- Controls the passage of organic molecules in and out of the cell **Nucleoid** \- Location of the DNA **Ribosomes** \- Used for protein synthesis. **Cytoskeleton** \- Maintains the cell's shape. \- Secures organelles in specific positions \- Allows cytoplasm and vesicles to move within the cell \- Enables unicellular organisms to move independently **Flagella/pili** \- Cellular locomotion. ### **ANIMAL CELLS**  **Nucleus**: The central organelle in eukaryotic cells that contains the genetic material (DNA) and controls cell activities. **Chromatin**: The material consisting of DNA and proteins found in the nucleus, which condenses to form chromosomes during cell division. **Nucleolus**: A small, dense region within the nucleus where ribosomal RNA (rRNA) is produced and assembled. **Nuclear Envelope:** A double membrane that surrounds the nucleus, protecting its contents and regulating the exchange of materials (like RNA and proteins) between the nucleus and the rest of the cell. **Peroxisome**: A small organelle involved in detoxifying harmful substances and breaking down fatty acids. **Rough Endoplasmic Reticulum (RER)**: A membrane-bound organelle with ribosomes on its surface, involved in protein synthesis and modification. **Smooth Endoplasmic Reticulum (SER)**: An organelle involved in lipid synthesis and detoxification processes, lacking ribosomes on its surface. **Cytoskeleton**: A network of protein filaments and tubules that provides structural support and facilitates movement within the cell. **Microtubules**: Hollow tubes made of protein that help maintain cell shape, assist in cell division, and provide tracks for organelles to move within the cell. **Centrosome**: A structure that organizes microtubules and plays a crucial role in cell division by helping to form the spindle fibers. **Intermediate Filaments**: Strong, rope-like fibers that provide mechanical support and maintain the cell\'s shape, especially in tissues subject to stress (like skin). **Microfilaments**: Thin, thread-like fibers made of actin that help with cell movement, shape, and contraction during processes like muscle movement. **Cell membrane**: A semi-permeable barrier surrounding the cell, controlling the movement of substances in and out **Lysosome**: An organelle containing digestive enzymes that break down waste materials and cellular debris. **Golgi Apparatus**: A cell organelle that modifies, sorts, and packages proteins and lipids for transport or secretion. **Cytoplasm**: The jelly-like substance within a cell, where organelles are suspended and various cellular processes occur. **Mitochondria**: The powerhouse of the cell, generating energy (ATP) through cellular respiration. **Ribosome**: Synthesizing proteins by translating genetic information from mRNA. It can be found either floating freely in the cytoplasm or attached to the RER. **Vesicle**: A membrane-bound vesicle formed around a particle engulfed by a cell during phagocytosis, used to digest harmful particles or pathogens. ### **PLANT CELLS** **Plasmodesmata**: Channels between plant cells that allow for the transport of substances and communication. **Cell Wall**: Rigid outer layer made of cellulose that provides structure and protection to plant cells. **Plasma Membrane**: Semi-permeable membrane surrounding the cell, controlling the movement of substances in and out. **Cytoplasm**: Jelly-like substance inside the cell where organelles are suspended and cellular processes occur. **Central Vacuole**: Large storage organelle in plant cells that holds water, nutrients, and waste; helps maintain turgor pressure. **Cytoskeleton**: Network of fibers (microtubules, microfilaments, and intermediate filaments) that provide structural support, shape, and help in movement within the cell. **Chloroplast**: Organelle containing chlorophyll, responsible for photosynthesis, converting sunlight into chemical energy. **Plastid**: Group of plant organelles, including chloroplasts, that are involved in storage or synthesis of food. **Peroxisome**: Organelle that breaks down fatty acids and detoxifies harmful substances using enzymes. **Mitochondria**: Powerhouse of the cell; generates energy (ATP) through cellular respiration. **Golgi Apparatus**: Stacks of membranes that modify, package, and transport proteins and lipids within the cell. **Ribosomes**: Protein-making structures found in the cytoplasm or on the rough ER. **Nucleus**: The control center of the cell, containing genetic material (DNA) and regulating cellular activities. **Rough Endoplasmic Reticulum (Rough ER)**: Membrane system studded with ribosomes, involved in protein synthesis and transport. **Smooth Endoplasmic Reticulum (Smooth ER)**: Membrane system without ribosomes, involved in lipid synthesis and detoxification.