Tiêu đề 21. THE DYNAMIC CELL – STRUCTURES AND FUNCTIONS OF CELLULAR COMPONENTS.pdf ✅

PHARMD GURU Page 2  Rough ER – Site of protein synthesis (with ribosomes).  Smooth ER – Involved in lipid synthesis and detoxification. o Golgi Apparatus – Modifies, packages, and transports proteins and lipids. o Lysosomes – Contains digestive enzymes for breaking down waste. o Cytoskeleton – Provides structural support and enables movement. C. CELL FUNCTION AND SPECIALIZATION:  Different cells are specialized to perform specific functions.  Example: Muscle cells contain more mitochondria for energy production, while nerve cells have long axons for signal transmission.  Cells work together in multicellular organisms, allowing division of labor and efficient functioning. 2) CELL AND MACROMOLECULES: Cells are classified into prokaryotic and eukaryotic cells, each with a specific structure and function. A. CELLULAR CLASSIFICATION: FEATURE PROKARYOTIC CELLS EUKARYOTIC CELLS Size Small (1-10 μm) Larger (10-100 μm) Nucleus Absent (DNA in nucleoid) Present (DNA in nucleus) Membrane-bound Organelles Absent Present (Mitochondria, ER, Golgi, etc.) Ribosomes 70S (smaller) 80S (larger) Cell Division Binary fission Mitosis or meiosis Examples Bacteria, archaea Animal, plant, fungal, and protist cells UNICELLULAR VS. MULTICELLULAR ORGANISMS:  Unicellular organisms – A single cell performs all life functions (e.g., bacteria, amoebas).  Multicellular organisms – Specialized cells work together (e.g., humans, plants).
PHARMD GURU Page 3 B. SUBCELLULAR ORGANELLES: Each organelle in a eukaryotic cell has a specific function. MAJOR ORGANELLES AND THEIR FUNCTIONS: ORGANELLE STRUCTURE FUNCTION Nucleus Surrounded by a nuclear envelope; contains chromatin (DNA). Stores genetic material regulates gene expression. Mitochondria Double membrane with inner folds (cristae). Produces ATP (energy). Rough ER Covered with ribosomes. Synthesizes proteins. Smooth ER Lacks ribosomes. Synthesizes lipids, detoxifies drugs. Golgi Apparatus Flattened sacs (cisternae). Modifies, sorts, and transports proteins and lipids. Lysosomes Membrane-bound vesicles with enzymes. Digests waste, pathogens, and damaged organelles. Cytoskeleton Network of protein filaments. Maintains cell shape, enables movement. C. MACROMOLECULES: Cells are made up of four major types of macromolecules: MACROMOLECULE STRUCTURE FUNCTION EXAMPLES Proteins Amino acid chains (polypeptides). Enzymes, structural support, transport, signaling. Actin, hemoglobin, antibodies. Nucleic Acids DNA & RNA (nucleotide chains). Store and transmit genetic information. DNA, mRNA, tRNA. Carbohydrates Sugar molecules (monosaccharides, polysaccharides). Energy storage, structural support, cell recognition. Glucose, glycogen, cellulose. Lipids Fatty acids, phospholipids, steroids. Energy storage, cell membrane structure, signaling. Triglycerides, cholesterol.
PHARMD GURU Page 4 D. LARGE MACROMOLECULAR ASSEMBLIES: Macromolecular assemblies consist of multiple macromolecules working together. Examples of Large Macromolecular Assemblies: MACROMOLECULAR ASSEMBLY STRUCTURE FUNCTION Ribosomes Composed of rRNA and proteins. Synthesizes proteins. Proteasomes Cylindrical protein complex. Degrades misfolded proteins. Cytoskeleton Network of microtubules, actin filaments, and intermediate filaments. Supports cell shape, movement, and intracellular transport.  Ribosomes translate mRNA into proteins.  Proteasomes degrade damaged or misfolded proteins.  The cytoskeleton enables cell movement and structural integrity. FUNCTIONAL SIGNIFICANCE OF MACROMOLECULAR ASSEMBLIES IN CELLULAR PROCESSES:  Protein Synthesis and Degradation – Ribosomes synthesize proteins, while proteasomes break down misfolded proteins.  Cell Division – The cytoskeleton forms the mitotic spindle during cell division.  Intracellular Transport – Microtubules guide the movement of organelles and vesicles. 3) CHROMOSOME STRUCTURE: Understanding chromosome structure is essential to learning how genetic material is stored, replicated, and inherited in cells. The organization of chromosomes differs significantly between prokaryotic and eukaryotic organisms, influencing gene expression and regulation. A. PROKARYOTIC CHROMOSOME STRUCTURE: Prokaryotic organisms, primarily bacteria, have a simple chromosome structure suited for their rapid growth and adaptability. Unlike eukaryotes, prokaryotic cells