THE FUNDAMENTAL UNIT OF LIFE CLASS IX.ppt
- 1. THE FUNDAMENTAL UNIT OF LIFE:CELL CLASS IX
- 2. Cells Smallest living unit Most are microscopic
- 3. Discovery of Cells Robert Hooke (1665) Observed sliver of cork Saw “row of empty boxes” Coined the term cell
- 4. Cell theory (1839)Theodor Schwann & Matthias Schleiden “ all living things are made of cells” (1855) Rudolf Virchow “Omnis cellula e cellula ” all cells arise from pre- existing cells
- 5. Principles of Cell Theory All living things are made of cells Smallest living unit of structure and function of all organisms is the cell All cells arise from preexisting cells (this principle discarded the idea of spontaneous generation)
- 6. Cell Size
- 7. Cells Have Large Surface Area-to-Volume Ratio
- 8. Characteristics of All Cells A surrounding membrane Protoplasm – cell contents in thick fluid Organelles – structures for cell function Control center with DNA
- 9. Cell Types Prokaryotic Eukaryotic
- 10. Prokaryotic Cells First cell type on earth Cell type of Bacteria and Archaea
- 11. Prokaryotic Cells No membrane bound nucleus Nucleoid = region of DNA concentration Organelles not bound by membranes
- 12. Eukaryotic Cells Nucleus bound by membrane Include fungi, protists, plant, and animal cells Possess many organelles Protozoan
- 14. THE UNIVERSE INSIDE OUR CELLS Zoom into your own body to see the different cells that make up your heart, brain and bones. These trillions building block of cells are communicating with each other every moment of our lives. As the house is made by BRICKS.
- 16. ANIMAL CELL
- 17. PLANT CELL
- 19. CELL ORGANELLES The cellular components are called the Cell Organelles. These cell organelles are membrane-bound, present within the cells and are distinct in their structures and functions. They coordinate with their functions efficiently for the normal functioning of the cell. There are various organelles present within the cell and are classified into three categories based on the presence or absence of membrane.
- 20. TYPES OF CELL ORGANELLES Organelles without membrane: The Cell wall, Ribosomes, Centrosome and Cytoskeleton are without membrane-bound cell organelles. Single membrane-bound organelles: Vacuole, Lysosome, Golgi Apparatus, Endoplasmic Reticulum are single membrane-bound organelles present only in a eukaryotic cell. Double membrane-bound organelles: Mitochondria and chloroplast are double membrane-bound organelles present only in a eukaryotic cell.
- 21. CELL ORGANELLES
- 22. Movement Across the Plasma Membrane A few molecules move freely Water, Carbon dioxide, Ammonia, Oxygen Carrier proteins transport some molecules Proteins embedded in lipid bilayer Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins
- 24. Membrane Proteins 1. Channels or transporters Move molecules in one direction 2. Receptors Recognize certain chemicals
- 25. Membrane Proteins 3. Glycoproteins Identify cell type 4. Enzymes Catalyze production of substances
- 26. CELL MEMBRANE FUNCTION Passive Transport Active Transport Endocytosis (phagocytosis & pinocytosis) Exocytosis
- 27. Passive Transport No energy required Move due to gradient differences in concentration, pressure, charge Move to equalize gradient High moves toward low
- 28. Types of Passive Transport 1. Diffusion 2. Osmosis 3. Facilitated diffusion
- 29. Diffusion Molecules move to equalize concentration
- 30. Osmosis Special form of diffusion Fluid flows from lower solute concentration Often involves movement of water Into cell Out of cell
- 31. Solution Differences & Cells solvent + solute = solution Hypotonic Solutes in cell more than outside Outside solvent will flow into cell And cell will swell Isotonic Solutes equal inside & out of cell no transport Hypertonic Solutes greater outside cell Fluid will flow out and shrink
- 33. Facilitated Diffusion Differentially permeable membrane Channels (are specific) help molecule or ions enter or leave the cell Channels usually are transport proteins (aquaporins facilitate the movement of water) No energy is used
- 34. Process of Facilitated Transport Protein binds with molecule Shape of protein changes Molecule moves across membrane
- 35. Active Transport Molecular movement Requires energy (against gradient) Example is sodium-potassium pump
- 36. Endocytosis Movement of large material Particles Organisms Large molecules Movement is into cells Types of endocytosis bulk-phase (nonspecific) receptor-mediated (specific)
- 37. Process of Endocytosis Plasma membrane surrounds material Edges of membrane meet Membranes fuse to form vesicle
- 38. Forms of Endocytosis Phagocytosis – cell eating Pinocytosis – cell drinking
- 39. Exocytosis Reverse of endocytosis Cell discharges material
- 40. Exocytosis Vesicle moves to cell surface Membrane of vesicle fuses Materials expelled
- 41. Cell Walls Found in plants, fungi, & many protists Surrounds plasma membrane
- 42. Cell Wall Differences Plants – mostly cellulose Fungi – contain chitin Bactria- Peptidoglycon or Murin
- 43. Cytoplasm Viscous fluid containing organelles components of cytoplasm Interconnected filaments & fibers Fluid = cytosol Organelles (not nucleus) storage substances
- 44. Centrioles Pairs of microtubular structures Play a role in cell division
- 45. DNA Hereditary material Chromosomes DNA Protiens Form for cell division Chromatin
- 46. Nucleolus Most cells have 2 or more Directs synthesis of RNA Forms ribosomes
- 47. Endoplasmic Reticulum Helps move substances within cells Network of interconnected membranes Two types Rough endoplasmic reticulum Smooth endoplasmic reticulum
- 48. Rough Endoplasmic Reticulum Ribosomes attached to surface Manufacture protiens Not all ribosomes attached to rough ER May modify proteins from ribosomes
- 49. Smooth Endoplasmic Reticulum No attached ribosome Has enzymes that help build molecules Carbohydrates Lipids
- 50. Golgi Apparatus Involved in synthesis of plant cell wall Packaging & shipping station of cell
- 51. Golgi Apparatus Function 1. Molecules come in vesicles 2. Vesicles fuse with Golgi membrane 3. Molecules may be modified by Golgi
- 52. Golgi Apparatus Function (Continued) 4. Molecules pinched-off in separate vesicle 5. Vesicle leaves Golgi apparatus 6. Vesicles may combine with plasma membrane to secrete contents
- 54. Lysosomes Contain digestive enzymes Functions Aid in cell renewal Break down old cell parts Digests invaders
- 55. CELL ORGANELLES 1 NUCLEUS 2 GOLGI BODY 3 PLASMA MEMBRANE 4 CYTOPLASM 5 ENDOPLASMIC RETICULUM 6 MITOCHONDRIA 7 LYSOSOME 8 VACUOLES 9 RIBOSOMES 10 MICROBODIES (a)PEROXIXOMES (b)GLYOXYSOME DISCOVERY 1 ROBERT BROWN(1831) 2 CAMEILLIO GOLGI 3 SCHWANN(1838) 4 STRASBURGER(1882) 5 PORTER(1943)AND NAMED IN(1953) 6 ALTAMAN(1894)AND NAMED BY BENDA(1897) 7 de DUVE(1955) 8 SPALLANZONI 9 ROBINSON AND BROWN (1953) IN PLANT CELL AND PALADE(1955) IN ANIMAL CELL 10 RHODIN(1954) (a)de DUVE(1965) (b)BRIEDENBACH(1967)
- 57. End Chapter