1 / 25

Cell Transport

Cell Transport. Modern Biology Chapter 5. Passive transport. Transport across a membrane without the expense of energy Video. Equilibrium. Equal concentration of molecules of a substance throughout a space All things move toward equilibrium unless energy is added. Diffusion.

dessa
Télécharger la présentation

Cell Transport

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cell Transport Modern Biology Chapter 5

  2. Passive transport • Transport across a membrane without the expense of energy • Video

  3. Equilibrium • Equal concentration of molecules of a substance throughout a space • All things move toward equilibrium unless energy is added

  4. Diffusion • random movement of molecules • Involves molecules that are small enough to fit between the phospholipids • Molecules move from areas of higher concentration to areas of lower concentration • Example: perfume or food dye

  5. What affects the rate of diffusion?

  6. Osmosis • Diffusion of water across a semi-permeable membrane • Water moves from areas of high water concentration to areas of lower water concentration

  7. Osmotic Pressure

  8. Osmotic pressure • Hypertonic • [solute] inside cell < [solute] outside cell • Water moves out of cells • Cell collapses • Video

  9. Hypotonic [solute] outside cell < [solute] inside cell Water moves into cells Cell explodes Osmotic pressure

  10. Osmotic pressure • Isotonic: water levels are even inside and outside cell • [solute] outside cell = [solute] inside cell • Cell remains in balanced equilibrium

  11. Osmotic pressure • Cells attempt to prevent death due to osmotic pressure in a number of ways • Cell wall: rigid cell wall prevents membrane from rupturing (turgor pressure) • Pump out water: specialized organelles called vacuoles remove excess water • Bathe cells in blood: blood is fairly isotonic with cells

  12. Facilitated diffusion • Diffusion of specific molecules • Works with the aid of carrier proteins • Each carrier protein is molecule specific • Diffusion through ion channels • Facilitated diffusion flick

  13. Ion channels • allow passage of ions • ions are not lipid soluble so they need help • each specific to one kind of ion • may always be open or have “switches”

  14. Active Transport Active Transport

  15. Example: Na+/K+ pump • Cells pump Na+ out and K+ in • For every 3 Na+ that exit cell, 2 K+ enter • Ions affect shape of protein causing the appropriate channels to open and close. • Creates a charge across the membrane • Outside membrane has + charge • Inside membrane has a – charge • Allow for electrical conduction • Sodium potassium pump • Another Na+/K+ pump

  16. Active transport • Movement across a semi-permeable membrane that requires the use of energy • Used to move molecules against the concentration gradient • Video

  17. Active Transport • Endocytosis: movement of large molecules into cell by pinching off of the cell membrane • Pinocytosis: movement of water • Phagocytosis: movement of solids • Exocytosis: endocytosis in reverse • Endo and Exocytosis • ER and Golgi animation • Internal Transport

  18. Transport movies • More transport • Cotransport • The Inner Life of Cells • Inner Life with Narrative

  19. Evolution of multi-cellular organization The origin of eukaryotic cells The endosymbiont theory: Lynn Margulis

  20. Stromatolites are good evidence Stromatolites and their close cousins the thrombolites, are rock-like buildups of microbial mats that form in limestone- or dolostone-forming environments.

  21. Evolution of Multicellular Organisms

  22. Some Bacteria were more useful “confined and alive” than as food

More Related