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Cell Structure and Transport

Explore cell theory, compare prokaryotic and eukaryotic cells, understand plasma membrane functions and components in cellular transport.

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Cell Structure and Transport

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  1. Cell Structure and Transport

  2. 7-1 Objectives • Describe the tenets of the cell theory • Compare the characteristics of prokaryotic and eukaryotic cells • Describe the parts of a light and electron microscope

  3. Cellular Structure and Function Chapter 7 7.1 Cell Discovery and Theory The Cell Theory • All organisms are composed of one or more cells. • The cell is the basic unit of structure and organization of organisms. • All cells come from preexisting cells.

  4. Cellular Structure and Function Chapter 7 7.1 Cell Discovery and Theory • Basic Cell Types • All cells have a plasma membrane • Prokaryotic Cell • Simple structure • Contains a plasma membrane • Does not contain membrane-bound organelles • No nucleus 11,000x

  5. Cellular Structure and Function Chapter 7 7.1 Cell Discovery and Theory Eukaryotic Cell • More complex structure • Contains a plasma membrane • Membrane cell organelles

  6. 7.2 The Plasma Membrane Objectives • Describe how a cell’s plasma membrane functions • Identify the roles of proteins, carbohydrates, and cholesterol in the plasma membrane

  7. Cellular Structure and Function Chapter 7 7.2 The Plasma Membrane Plasma Membrane • Thin, flexible boundary between the cell and its environment

  8. The plasma membrane controls the movement of substances into and out of the cell. Cellular Structure and Function Chapter 7 7.2 The Plasma Membrane Selective Permeability

  9. Cellular Structure and Function Chapter 7 7.2 The Plasma Membrane • The plasma membrane is composed of the phospholipidbilayer.

  10. Cellular Structure and Function Chapter 7 7.2 The Plasma Membrane Fluid Mosaic Model • “float” in the membrane. Other Components • Proteins • Cholesterol • Carbohydrates

  11. Cellular Structure and Function Chapter 7 7.2 The Plasma Membrane Proteins • Transmit signals inside the cell • support structure • Provide pathways for substances to enter and leave

  12. Cellular Structure and Function Chapter 7 7.2 The Plasma Membrane Cholesterol • Prevents fatty acid tails from sticking together

  13. Cellular Structure and Function Chapter 7 7.2 The Plasma Membrane Carbohydrates • Identify chemical signals

  14. Plasma membrane

  15. 7.3 Structures and Organelles Objectives 1. Identify the structure and function of the parts of a typical eukaryotic cell. 2. Compare and contrast structures of plant and animal cells.

  16. Cellular Structure and Function Chapter 7 7.3 Structures and Organelles Plant and Animal Cell Structures Plant Cell Animal Cell

  17. Cellular Structure and Function Chapter 7 7.3 Structures and Organelles

  18. Cellular Structure and Function Chapter 7 7.3 Structures and Organelles

  19. Cellular Structure and Function Chapter 7 7.3 Structures and Organelles

  20. Cellular Structure and Function Chapter 7 7.3 Structures and Organelles

  21. Cellular Structure and Function Chapter 7 7.3 Structures and Organelles Cilia • Short, numerous projections that look like hairs 400x Flagella • Longer and less numerous than cilia • Create movement with a whiplike motion 26,367x

  22. Summary of cell parts • http://glencoe.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::550::400::/sites/dl/free/0078695104/383931/Table7_1a.swf::Summary%20of%20Cell%20Structures%20-%20A • http://glencoe.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::550::400::/sites/dl/free/0078695104/383931/Table7_1b.swf::Summary%20of%20Cell%20Structures%20-%20B • http://glencoe.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::550::400::/sites/dl/free/0078695104/383931/Table7_1c.swf::Summary%20of%20Cell%20Structures%20-%20C

  23. 7.4 Cellular Transport Objectives • Explain the processes of diffusion, facilitated diffusion, and active transport • Predict the effect of a hypotonic, hypertonic, or isotonic solution on a cell • Discuss how large particles enter and exit cells

  24. Cell Membranes& Movement Across Them

  25. Cell (plasma) membrane • Cells need an inside & an outside… • separate cell from its environment • cell membrane is the boundary IN food - sugars - proteins - fats salts O2 H2O OUT waste - ammonia - salts - CO2 - H2O products - proteins cell needs materials in & products or waste out

  26. Building a membrane • How do you build a barrier that keeps the watery contents of the cell separate from the watery environment? FATS LIPIDS Remember: oil & water don’t mix!! What substance do you know that doesn’t mix with water?

  27. inside cell outside cell Lipids of cell membrane • Membrane is made of special kind of lipid • phospholipids • “split personality” • Membrane is a double layer • phospholipid bilayer “attracted to water” phosphate lipid “repelled by water”

  28. Semi-permeable membrane • Cell membrane controls what gets in or out • Need to allow some materials — but not all — to pass through the membrane • semi-permeable • only some material can get in or out So what needs to get across the membrane? lipids aa O2 H2O salt sugar waste

  29. inside cell outside cell Crossing the cell membrane • What molecules can get through the cell membrane directly? • fats and oils can pass directly through lipid salt waste but… what about other stuff? sugar aa H2O

  30. Cell membrane channels • Need to make “doors” through membrane • protein channels allow substances in & out • specific channels allow specific material in & out • H2O channel, salt channel, sugar channel, etc. inside cell H2O aa sugar salt outside cell waste

  31. How do you build a semi-permeable cell membrane? • Channels are made of proteins • proteins both “like” water & “like” lipids bi-lipid membrane protein channelsin bi-lipid membrane

  32. Protein channels • Proteins act as doors in the membrane • channels to move specific molecules through cell membrane HIGH LOW

  33. Movement through the channel • Why do molecules move through membrane if you give them a channel? HIGH ? LOW ?

  34. Molecules move from high to low • Diffusion • move from HIGH to LOW concentration

  35. Diffusion • Move from HIGH to LOW concentration • passive transport • no energy needed diffusion of water diffusion osmosis

  36. Simple Diffusion • Move from HIGH to LOW fat fat fat Which way will fat move? inside cell fat fat fat LOW HIGH fat outside cell fat fat fat fat fat fat fat

  37. Facilitated Diffusion • Move from HIGH to LOWthrough a channel sugar sugar sugar sugar inside cell sugar sugar LOW Which way will sugar move? HIGH outside cell sugar sugar sugar sugar sugar sugar sugar

  38. Diffusion • Move from HIGH to LOW concentration • directly through membrane • simple diffusion • no energy needed • help through a protein channel • facilitated diffusion (with help) • no energy needed HIGH LOW

  39. inside cell inside cell outside cell outside cell Simple vs. facilitated diffusion simple diffusion facilitated diffusion lipid H2O protein channel H2O

  40. Active transport • Cells may need molecules to move against concentration “hill” • need to pump “uphill” • from LOW to HIGHusing energy • protein pump • requires energy • ATP ATP

  41. Transport summary simplediffusion facilitateddiffusion ATP activetransport

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