1 / 38

Diffusion and Transport

Diffusion and Transport. Ms. Klinkhachorn November 29, 2010 AP Biology. Announcements:. Quiz on THURSDAY Organelles Eukaryotes and Prokaryotes Plant Cells and Animal Cells Membranes Passive Transport. Identify the Parts. Phospholipid Bilayer - Characteristics.

Télécharger la présentation

Diffusion and 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. Diffusion and Transport Ms. Klinkhachorn November 29, 2010 AP Biology

  2. Announcements: • Quiz on THURSDAY • Organelles • Eukaryotes and Prokaryotes • Plant Cells and Animal Cells • Membranes • Passive Transport

  3. Identify the Parts

  4. Phospholipid Bilayer - Characteristics

  5. Permeability of the Bilayer • Hydrophobic molecules can pass through, but hydrophilic molecules can not (at least not easily) • Polar molecules = hydrophilic • Examples: Sugars, charged atoms (K+) and molecules • Nonpolar molecules = hydrophobic • Examples: oxygen, carbon dioxide

  6. Transport Proteins • Help materials that are big or hydrophilic pass through the membrane easily • Substance specific • If it’s supposed to translocate water and sugar, it will only translocate water and sugar • Two Kinds: • Channel Proteins • Carrier Proteins

  7. Transport Proteins

  8. Efficacy of Transport Proteins • 3 billion water molecules can move across the membrane using an aquaporin per second • Glucose moves across the membrane 50,000x faster with a transport protein than by itself

  9. Passive Transport • Diffusion ACROSS A MEMBRANE • Diffusion = movement of molecules so that they spread out evenly in an available space • Does NOT require energy or use a transport protein • Once the molecules spread out they are in a state of equilibrium • Substances diffuse from a high concentration to a low concentration • They move down their own concentration gradient

  10. Diffusion of Sugar

  11. Concentration Gradient

  12. Types of Passive Transport • Simple Diffusion • Facilitated Diffusion • Osmosis

  13. Example: Gas Exchange

  14. Simple Diffusion

  15. Facilitated Diffusion • Diffusion that requires a transport protein

  16. Osmosis • Diffusion of water across a selectively permeable membrane (where the solute cannot go through the membrane) • Water will move from an area of lower solute concentration to an area of higher solute concentration • Wants to balance out the solute concentrations

  17. Osmosis

  18. Hypertonic Solutions • “Hyper” means “above” • A hypertonic solution has a higher concentration of solute • This means that water is less concentrated • A cell placed in a hypertonic solution will SHRINK due to water loss.

  19. Plant Cells in a Hypertonic Solution

  20. Before and After

  21. Hypotonic Solutions • “Hypo” means “below” • A hypotonic solution has a lower concentration of solute • This means that water is more concentrated • A cell placed in a hypotonic solution will SWELL due to water intake.

  22. Isotonic Solutions • “Iso” means “equal” • An isotonic solution has an equal concentration of solute • A cell placed in an isotonic solution will remain unchanged • There will still be movement of water, though there is NO NET GAIN.

  23. DNA – November 30, 2010 Answer these on the back of your study guide: • What is diffusion? How is it different from passive transport? • What do the word forms “hypo”, “hyper”, “osmo” and “iso” mean? • Describe what is happening in the picture.

  24. Water Balance in Animal Cells • If the cell swells too much, it can burst. • This is called lysis. The cell lyses. • If the cell shrivels too much, it can die.

  25. Examples (Animal Cell)

  26. Water Balance in Plant Cells • Cells still swell in hypotonic environment, but the wall is more rigid. • Water uptake makes the cell turgid (firm). • This is a plant’s healthy state. • If the cell is in an isotonic environment, it is flaccid (limp) • If the cell is in a hypertonic environment, it plasmolyzes (a process called plasmolysis) • The cell membrane pulls away from the cell wall as water is lost • Can cause death.

  27. Examples (Plant Cell)

  28. Saltwater fish – Predict what happens to fish in these environments.

  29. Saltwater Fish • Saltwater fish are constantly swimming in a hypertonic environment • Fish are consistently losing water from their bodies • In order to maintain water balance, the fish have to drink a lot of saltwater and pump salt out of their bodies

  30. Freshwater fish – Predict what happens to fish in these environments.

  31. Freshwater Fish • Freshwater fish live in a hypotonic environment • Water is constantly moving into their cells • These fish pee regularly in order to get rid of this water

  32. Osmoregulation • Osmoregulation = the control of water balance • Certain organisms are adapted to deal with this • Sea animals • Paramecium

  33. Paramecium • Paramecium lives in pond water, which is hypotonic to the cell. • What effect does the hypotonic environment have on this? • How might the paramecium adapt?

  34. Contractile Vacuole

  35. DNA – December 1, 2010 • Give an example of how organisms have adapted to deal with hypertonic or hypotonic living conditions. • Explain what a hypertonic and a hypotonic environment will do to a piece of celery.

  36. Osmosis Practice

  37. Active Transport • Active transport = movement of substances AGAINST their concentration gradient • Requires energy  ATP • Uses a transport protein, specifically a carrier protein • This allows cells to maintain certain solute concentrations

  38. Sodium-Potassium Pump

More Related