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6th Grade Science / Lesson 6 - Pass Through a Barrier

Pass Through a Barrier
What will we be learning today?


  • In this lesson, we are going to learn all about what can pass through a barrier.


What Can Pass Through a Barrier?


  • The cell membrane is a kind of barrier, something like the tea bag. Cells get food, oxygen, and other substances from the environment.

  • They also release wastes, such as the gas carbon dioxide. Substances move in and out of the cell through the cell membrane.

  • Some kinds of molecules are able to pass through a cell membrane by diffusion. That is, they move from areas of high concentration to low concentration.


  • Molecules of sugar, water, oxygen ,and carbon dioxide do not require energy to move from high to low concentration. Such movement through cell membranes without the use of energy is called passive transport.

  • Other molecules, such as proteins and bacteria, are so large they can only enter the cell with the help of special processes that take place in the cell membrane.



  • Diffusion of oxygen and carbon dioxide through cell membrane


Let's Review What We Learned Today!


  • Now complete your worksheet by using this Presentation