Cell Transport Video and Questions

 

Watch the following video clips from Discovery Education below to learn more about active and passive transport.  You may want to download the questions below and make notes of the answers you discover. Doing so will prepare you for an upcoming assignment check.

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Check your understanding of this segment you've just viewed by answering the following.

  1. How would you compare and contrast diffusion and osmosis?
  2. Food can be preserved by salting it. What would happen to the water inside bacteria when they are in an extremely salty environment?
  3. The contractile vacuole of a Paramecium constantly pumps water out of the cell. Why would a Paramecium need to remove water?
  4. After a long bath your finger tips look all wrinkled. Why?
  5. "Reverse osmosis" is a method of purifying water. Considering the meaning of osmosis, explain how reverse osmosis would make water more pure.
  6. Some people claim to "learn by osmosis" – does this really make sense?

 

Try it out!!

Pour a teaspoon full of vinegar onto a paper towel or cloth and put it into a plastic bag. Close the bag and wait about five minutes. Hold the bag at arm's length in a room without any breeze or draft. Slowly remove the cloth from the bag. Count how many breaths you can take before you smell the vinegar. This gives you a rough idea of the speed of diffusion of vinegar molecules through air.

Inside and outside cells, water will diffuse from higher to lower concentration until it reaches equilibrium. This is called osmosis. The cytoplasm of a cell has many materials dissolved in it. When the cell is placed in pure water, the net flow of water by osmosis is into the cell.

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Check your understanding of this segment by completing the following.

  1. Explain the difference between endocytosis and exocytosis.
  2. What two organelles are involved in endocytosis?
  3. What is the role of adenosine triphosphate (ATP) in active transport?
  4. A Paramecium's contractile vacuole pumps water out of the cell. Is this active or passive transport?
  5. Describe the role of carrier proteins in active transport.

 



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