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UNIT C • CHAPTER 8
LESSON 1
Passive Transport
Passive/Active Transport
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Active Transport
Molecules
Cell membrane
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Vesicle
Cells expend no energy in passive transport.
Substances diffuse across the cell membrane
from regions of high concentration to regions
of low concentration.
Cells must expend energy to move materials
across the cell membrane from regions of low
concentration to regions of high concentration.
Forming vesicles is one way this is done.
Teaching Transparencies
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