The Cell & Cell Cycle-detailed structure and function of organelles.pptx

The Cell & Cell Cycle-detailed structure and function of organelles.pptx

• 1.
  PREPARED BY Prof. ASHISHN. UMALE M. PHARM IN PHARMACOLOGY ASSISTANT PROFESSOR SHRADDHA INSTITUTE OF PHARMACY, WASHIM-444505 HUMAN ANATOMY AND PHYSIOLOGY - I
• 2.
  Cell Organelles: Structure and Functions Exploringthe remarkable machinery that powers every living cell
• 3.
  What Are CellOrganelles? Organelles are specialised structures within cells, each performing unique functions essential for cell survival. These microscopic components work in harmony, much like organs in the human body. They can be classified as membrane-bound (such as mitochondria and the nucleus) or non-membrane-bound (like ribosomes). Together, they maintain the cell's life processes, ensuring proper organisation and functionality. Understanding these structures reveals the extraordinary complexity hidden within every living cell.
• 4.
  The Plasma Membrane:The Cell's Gatekeeper Structure Phospholipid bilayer with embedded proteins forming a dynamic fluid mosaic model, creating a selective barrier Function Controls entry and exit of substances, protects cell integrity, and facilitates communication between cells Location Present in both plant and animal cells, forming the essential outer boundary of every living cell
• 5.
  Cytoplasm and Cytoskeleton: TheCell's Framework Cytoplasm Jelly-like fluid comprising water, salts, and organic molecules where organelles are suspended. This aqueous environment serves as the site of numerous vital chemical reactions. Cytoskeleton Dynamic network of protein filaments providing structural support, maintaining cell shape, & enabling movement and intracellular transport. Key Components Includes microtubules (largest), microfilaments (smallest), and intermediate filaments, each with distinct roles in cellular mechanics.
• 6.
  The Nucleus: ControlCentre of the Cell Double Membrane Protection Nuclear envelope with pores regulates molecular traffic in and out Genetic Storage DNA organised as chromosomes containing all hereditary information Control Hub Directs protein synthesis and coordinates all cellular activities Ribosome Assembly Nucleolus produces ribosomal subunits for protein production
• 7.
  Endoplasmic Reticulum: Manufacturingand Transport Hub A vast network of interconnected membranes continuous with the nuclear envelope, forming the cell's primary manufacturing facility.  Studded with ribosomes giving rough appearance.  Synthesises proteins destined for export or membrane incorporation.  Crucial for producing enzymes and hormones. Lacks ribosomes with tubular structure Synthesises lipids and steroid hormones Detoxifies harmful chemicals and stores calcium ions Rough ER Smooth ER
• 8.
  Golgi Apparatus: The Cell'sPost Office Receiving Accepts protein and lipid packages from the ER in transport vesicles Modification Chemically modifies molecules through enzymatic processing Sorting Labels and organises molecules for correct destinations Shipping Packages products into vesicles for transport throughout the cell Composed of flattened membrane sacs called cisternae, the Golgi produces lysosomes and secretory vesicles essential for cellular function.
• 9.
  Mitochondria: The Powerhouse "Withoutmitochondria, complex multicellular life as we know it would not exist." Double Membrane Structure Outer membrane encloses inner membrane with folded cristae, dramatically increasing surface area for energy production ATP Generation Produces adenosine triphosphate (ATP) through cellular respiration, providing chemical energy for all cellular activities Universal Presence Found in nearly all eukaryotic cells, with numbers varying by energy demands— muscle cells contain thousands
• 10.
  Lysosomes and Vacuoles:Waste Management and Storage Lysosomes Membrane-bound sacs containing powerful digestive enzymes that break down cellular waste, damaged organelles, and foreign materials. • Function as the cell's recycling centres • Protect the cell through controlled degradation • Aid in cellular defence mechanisms Vacuoles Versatile storage compartments that vary greatly in size and function between cell types. •Plant cells: large central vacuole maintains turgor pressure •Store water, nutrients, and waste products •Help maintain cellular homeostasis
• 11.
  Summary: The Orchestra ofOrganelles Each organelle plays a vital, interconnected role in maintaining cell survival and function. Like instruments in an orchestra, they work in perfect coordination to sustain life. Energy Production Mitochondria power cellular activities Protein Synthesis ER and ribosomes build essential molecules Waste Management Lysosomes maintain cellular cleanliness Nucleus directs all cellular operations Genetic Control Understanding organelles is fundamental to grasping how life functions at the cellular level—the foundation of all biological processes.
• 12.
  The Cell Cycle: UnderstandingMitosis and Meiosis Exploring the fundamental processes that drive growth, repair, and reproduction in all living organisms.
• 13.
  What is theCell Cycle? Life Cycle of a Cell The cell cycle represents the complete journey of a cell from formation to division, encompassing growth, DNA replication, and the creation of new cells. Two Major Phases Consists of interphase (G1, S, and G2 phases where the cell prepares) and M phase (mitosis or meiosis where division occurs). Preparation and Division Interphase prepares the cell through growth and DNA copying, while M phase executes the actual division into daughter cells.
• 14.
  Interphase: Preparing for Division G1Phase Growth Period The cell grows in size and performs its normal metabolic functions. At the restriction point, the cell commits to division. •Protein synthesis •Organelle production •Energy accumulation S Phase DNA Synthesis DNA replication occurs, duplicating each chromosome to form sister chromatids joined at the centromere. •Complete genome duplication •Histone synthesis •Centrosome duplication G2 Phase Final Preparation The cell prepares its cytoplasm, organelles, and proteins needed for the coming division process. •Tubulin synthesis •Organelle replication •Checkpoint verification
• 15.
  Mitosis: The Process ofSomatic Cell Division Purpose of Mitosis Essential for organism growth, tissue repair and regeneration, and asexual reproduction in certain organisms. Maintains genetic consistency across body cells. Genetic Outcome Produces two genetically identical diploid daughter cells, each containing the same number of chromosomes as the parent cell. Timeline Takes approximately one hour in actively dividing animal cells, though timing varies by cell type and organism.
• 16.
  The Five Stagesof Mitosis Prophase Chromosomes condense and become visible. Spindle fibres begin forming. Nuclear envelope breaks down. Prometaphase Chromosomes attach to spindle fibres via kinetochores at the centromere. Metaphase Chromosomes align at the cell's equator, forming the metaphase plate. Anaphase Sister chromatids separate and migrate to opposite poles of the cell. Telophase Nuclear envelopes reform around each set. Chromosomes decondense. Cytokinesis: Following telophase, the cytoplasm divides through a contractile ring, physically separating the cell into two distinct daughter cells.
• 17.
  Meiosis: Creating GeneticDiversity 1 Specialized Cell Division Occurs exclusively in germ cells within reproductive organs to produce gametes: sperm in males and eggs in females. 2 Meiosis I Reduction division separates homologous chromosome pairs, reducing chromosome number by half. 3 Meiosis II Equational division separates sister chromatids, similar to mitosis but without DNA replication beforehand. 4 Final Result Four genetically unique haploid cells, each containing half the original chromosome number.
• 18.
  Key Differences: Mitosisvs Meiosis Mitosis • One division cycle • Produces two daughter cells • Cells are genetically identical • Maintains diploid number • Occurs in somatic cells • No crossing over Meiosis • Two division cycles • Produces four daughter cells • Cells are genetically distinct • Reduces to haploid number • Occurs in germ cells only • Crossing over in prophase I Meiosis reduces chromosome number by half to maintain species chromosome count across generations, while mitosis preserves the complete genetic complement.
• 19.
  Crossing Over: TheGenetic Shuffle Homologue Pairing Maternal and paternal chromosomes align side by side during prophase I. DNA Exchange Chromosomes physically break and swap corresponding DNA segments at chiasmata points. Recombination DNA is repaired, creating chromosomes with new combinations of alleles. Genetic Variation Each gamete receives unique genetic combinations, increasing offspring diversity. This genetic shuffling, combined with independent assortment, ensures that each gamete is genetically unique, driving evolution and adaptation.
• 20.
  Why Cell DivisionMatters Mitosis in Action Enables organism growth from a single cell, replaces damaged or dead cells, and maintains healthy body tissues throughout life. Meiosis Importance Ensures sexual reproduction functions properly and creates genetic variation, which is essential for evolution and species adaptation. When Division Fails Errors in mitosis can cause uncontrolled cell growth leading to cancer. Meiosis errors result in genetic disorders like Down syndrome.
• 21.
  Summary: The Danceof Life at the Cellular Level Orchestrated Precision The cell cycle orchestrates life's continuity through precise, regulated growth and division processes. Complementary Processes Mitosis and meiosis are distinct yet complementary mechanisms, both vital for sustaining life. Foundation of Life Understanding these processes reveals the biological foundation of growth, reproduction, and heredity in all living organisms. "The cell cycle is not merely a biological process-it is the very essence of life's continuity, enabling organisms to grow, adapt, and pass genetic information through generations."