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CHAPTER 6 A TOUR OF THE CELL

CHAPTER 6 A TOUR OF THE CELL. Cytology: science/study of cells. Light microscopy resolving power~ measure of clarity Electron microscopy TEM ~ electron beam to study cell ultrastructure SEM ~ electron beam to study cell surfaces

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CHAPTER 6 A TOUR OF THE CELL

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  1. CHAPTER 6A TOUR OF THE CELL

  2. Cytology: science/study of cells • Light microscopy resolving power~ measure of clarity • Electron microscopy TEM ~ electron beam to study cell ultrastructure SEM ~ electron beam to study cell surfaces • Cell fractionation ~ cell separation; organelle study • Ultracentrifuge ~ cell fractionation; 130,000rpm

  3. A cell is a living unit greater than the sum of its parts • While the cell has many structures that have specific functions, they must work together.

  4. Prokaryotebacteria cells Types of cells - no organelles - organelles Eukaryoteanimal cells Eukaryoteplant cells

  5. Cell Types: Prokaryotic • Nucleoid: DNA concentration • No organelles with membranes • Ribosomes:protein synthesis • Plasma membrane: (all cells); semi-permeable • Cytoplasm/cytosol(all cells)

  6. Cell types: Eukaryotic • Nucleus:membrane enclosedorganelle containing chromosomes • Membrane bound organellesof specialized form and function • Generally larger than prokaryotic cells

  7. Cell Size • As cell size increases, the surface area to volume ratio decreases • Rates of chemical exchange may then be inadequate for cell size • Cell size, therefore, remains small

  8. Golgi mitochondria chloroplast ER Why organelles? • Specialized structures • specialized functions • cilia or flagella for locomotion • Containers • partition cell into compartments • create different local environments • separate pH, or concentration of materials • distinct & incompatible functions • lysosome & its digestive enzymes • Membranes as sites for chemical reactions • unique combinations of lipids & proteins • embedded enzymes & reaction centers • chloroplasts & mitochondria

  9. Cells gotta work to live! • What jobs do cells have to do? • make proteins • proteins control everycell function • make energy • for daily life • for growth • make more cells • growth • repair • renewal

  10. Proteins do all the work! proteins cells DNA Repeat after me… Proteins do all the work! organism

  11. Cells functions • Building proteins • read DNA instructions • build proteins • process proteins • folding • modifying • removing amino acids • adding other molecules • e.g, making glycoproteinsfor cell membrane • address & transport proteins

  12. The Protein Assembly Line Golgiapparatus ribosome ER Building Proteins • Organelles involved • nucleus • ribosomes • endoplasmic reticulum (ER) • Golgi apparatus • vesicles nucleus vesicles

  13. DNA chromosome histone protein nuclear pores nuclear pore nucleolus nuclear envelope Nucleus • Function • protects DNA • Structure • nuclear envelope • double membrane • membrane fused in spots to create pores • allows large macromolecules to pass through What kind of molecules need to pass through?

  14. large subunit small subunit ribosome Nucleolus • Function • ribosome production • build ribosome subunits from rRNA & proteins • exit through nuclear pores to cytoplasm & combine to form functional ribosomes rRNA & proteins nucleolus

  15. large subunit small subunit 0.08mm Ribosomes Rough ER Smooth ER Ribosomes • Function • protein production • Structure • rRNA & protein • 2 subunits combine

  16. Types of Ribosomes • Freeribosomes • suspended in cytosol • synthesize proteins that function in cytosol • Bound ribosomes • attached to endoplasmic reticulum • synthesize proteins for export or for membranes membrane proteins

  17. Endoplasmic Reticulum • Function • processes proteins • manufactures membranes • synthesis & hydrolysis of many compounds • Structure • membrane connected to nuclear envelope & extends throughout cell

  18. Types of ER rough smooth

  19. Smooth ER function • Membrane production • Many metabolic processes • synthesis • synthesize lipids • oils, phospholipids, steroids & sex hormones • hydrolysis • hydrolyze glycogen into glucose • in liver • detoxify drugs & poisons • in liver • ex. alcohol & barbiturates

  20. Membrane Factory • Build new membrane • synthesize phospholipids • builds membranes • ER membrane expands • bud off & transfer to other parts of cell that need membranes

  21. Rough ER function • Produce proteins for export out of cell • protein secreting cells • packaged into transport vesicles for export Which cellshave lot of rough ER?

  22. Golgi Apparatus

  23. protein vesicle budding from rough ER migrating transport vesicle fusion of vesicle with Golgi apparatus ribosome Vesicle transport

  24. Any Questions!!

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