Cell Structure and Function. Anatomy and Physiology
- 1. Cell Structure and Function
- 2. Cells • Smallest living unit • Most are microscopic
- 3. Cell theory • (1839)Theodor Schwann & Matthias Schleiden “ all living things are made of cells” • (50 yrs. later) Rudolf Virchow “all cells come from cells”
- 4. 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)
- 5. Cell Size
- 6. Characteristics of All Cells • A surrounding membrane • Protoplasm – cell contents in thick fluid • Organelles – structures for cell function • Control center with DNA
- 8. Plasma Membrane • Contains cell contents • Double layer of phospholipids & proteins
- 9. Phospholipids • Polar – Hydrophylic head – Hydrophobic tail • Interacts with water
- 10. 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
- 12. Membrane Proteins 1. Channels or transporters – Move molecules in one direction 2. Receptors – Recognize certain chemicals
- 13. Membrane Proteins 3. Glycoproteins – Identify cell type 4. Enzymes – Catalyze production of substances
- 14. Cytoplasm • Viscous fluid containing organelles • components of cytoplasm – Interconnected filaments & fibers – Fluid = cytosol – Organelles (not nucleus) – storage substances
- 15. Cytoskeleton • Filaments & fibers • Made of 3 fiber types – Microfilaments – Microtubules – Intermediate filaments • 3 functions: – mechanical support – anchor organelles – help move substances
- 16. A = actin, IF = intermediate filament, MT = microtubule
- 17. Cilia & Flagella • Provide motility • Cilia – Short – Used to move substances outside human cells • Flagella – Whip-like extensions – Found on sperm cells • Basal bodies like centrioles
- 18. Cilia & Flagella Structure • Bundles of microtubules • With plasma membrane
- 19. Centrioles • Pairs of microtubular structures • Play a role in cell division
- 20. Membranous Organelles • Functional components within cytoplasm • Bound by membranes
- 21. Nucleus • Control center of cell • Double membrane • Contains – Chromosomes – Nucleolus
- 22. Nuclear Envelope • Separates nucleus from rest of cell • Double membrane • Has pores
- 23. DNA • Hereditary material • Chromosomes – DNA – Protiens – Form for cell division • Chromatin
- 24. Nucleolus • Most cells have 2 or more • Directs synthesis of RNA • Forms ribosomes
- 25. Endoplasmic Reticulum • Helps move substances within cells • Network of interconnected membranes • Two types – Rough endoplasmic reticulum – Smooth endoplasmic reticulum
- 26. Rough Endoplasmic Reticulum • Ribosomes attached to surface – Manufacture protiens – Not all ribosomes attached to rough ER • May modify proteins from ribosomes
- 27. Smooth Endoplasmic Reticulum • No attached ribosomes • Has enzymes that help build molecules – Carbohydrates – Lipids
- 28. Golgi Apparatus • Involved in synthesis of plant cell wall • Packaging & shipping station of cell
- 29. Golgi Apparatus Function 1. Molecules come in vesicles 2. Vesicles fuse with Golgi membrane 3. Molecules may be modified by Golgi
- 30. 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
- 32. Lysosomes • Contain digestive enzymes • Functions – Aid in cell renewal – Break down old cell parts – Digests invaders
- 33. Vacuoles • Membrane bound storage sacs • More common in plants than animals • Contents – Water – Food – wastes
- 34. Mitochondria • Have their own DNA • Bound by double membrane
- 35. Mitochondria • Break down fuel molecules (cellular respiration) – Glucose – Fatty acids • Release energy – ATP
- 36. Review of Eukaryotic Cells
- 37. Review of Eukaryotic Cells
- 39. Molecule Movement & Cells • Passive Transport • Active Transport • Endocytosis (phagocytosis & pinocytosis) • Exocytosis
- 40. Passive Transport • No energy required • Move due to gradient – differences in concentration, pressure, charge • Move to equalize gradient – High moves toward low
- 41. Types of Passive Transport 1. Diffusion 2. Osmosis 3. Facilitated diffusion
- 42. Diffusion • Molecules move to equalize concentration
- 43. Osmosis • Special form of diffusion • Fluid flows from lower solute concentration • Often involves movement of water – Into cell – Out of cell
- 44. Solution Differences & Cells • solvent + solute = solution • Hypotonic – Solutes in cell more than outside – Outside solvent will flow into cell • Isotonic – Solutes equal inside & out of cell • Hypertonic – Solutes greater outside cell – Fluid will flow out of cell
- 46. 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
- 47. Process of Facilitated Transport • Protein binds with molecule • Shape of protein changes • Molecule moves across membrane
- 48. Active Transport • Molecular movement • Requires energy (against gradient) • Example is sodium-potassium pump
- 49. Endocytosis • Movement of large material – Particles – Organisms – Large molecules • Movement is into cells • Types of endocytosis – bulk-phase (nonspecific) – receptor-mediated (specific)
- 50. Process of Endocytosis • Plasma membrane surrounds material • Edges of membrane meet • Membranes fuse to form vesicle
- 51. Forms of Endocytosis • Phagocytosis – cell eating • Pinocytosis – cell drinking
- 52. Exocytosis • Reverse of endocytosis • Cell discharges material
- 53. Exocytosis • Vesicle moves to cell surface • Membrane of vesicle fuses • Materials expelled
- 54. End Chapter 5