Lab:!Passive!&!Active!Transport!
The cell membrane is semi-permeable. This means some materials are allowed through and some are
not. The size, shape, and charge of the molecules determines whether they can pass or not.
Passive Transport
• The movement of materials through a membrane without energy
• Diffusion: the movement of materials from high concentration to low concentration
• Osmosis: the diffusion of water through a membrane
Active Transport
• The process of using energy to move materials through a membrane
• Some materials, like sugar or salt, are too big to flow through the membrane
• Instead, the cell needs energy to move the molecule through a protein.
o What type of energy? ATP!
• Cells in our kidneys filter & remove salt from your blood through active transport.
Endocytosis
• Occurs when a large bit of material is captured with a pocket in the membrane
• The pocket breaks off & forms a package that moves into the cell
• Requires energy
• Essential nutrients, like iron, are absorbed into cells this way
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Exocytosis
• Occurs when a large bit of material needs to be removed from a cell
• A package of the materials travels through the cell to the membrane, joins it, and is expelled
• Requires energy
• Cells use this to flush out waste such as hormones
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