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Lesson Overview
7.3 Cell Transport
Lesson Overview
Cell Transport
The Cell Membrane
All cell membranes are made of phospholipids, proteins, cholesterol, and
glycoproteins
Lesson Overview
Cell Transport
Cell Transport
Materials must move into and out of the cell, across the membrane, to stay alive.
Water
Na+ ions
Cl- ions
O2
CO2
Lesson Overview
Cell Transport
Types of Cell Transport
PASSIVE
- does not use energy
• Diffusion
• Osmosis
• Facilitated Diffusion
ACTIVE
- uses energy
• Pumps
• Endocytosis
• Exocytosis
Lesson Overview
Cell Transport
Diffusion (No Energy Required)
Diffusion = materials move from high concentration to lower concentration
through the phospholipids.
Lesson Overview
Cell Transport
Facilitated Diffusion (No Energy Required)
Facilitated diffusion = Big molecules must pass through protein channels.
Lesson Overview
Cell Transport
Osmosis: An Example of Facilitated
Diffusion (No Energy Required)
Osmosis = the diffusion of water through a selectively permeable
membrane from HIGH to LOW.
Water moves in and out of cells by
using channel proteins called
aquaporins.
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Cell Transport
How Osmosis Works
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Cell Transport
Types of Solutions
Hypertonic = solution with lots of “stuff” dissolved in water.
Ex. Ocean Water, Iced Tea, High fructose corn syrup.
Hypotonic = solution with very little “stuff” dissolved in water.
Ex. Pure water, tap water.
Isotonic = solution that is equal to the environment.
Ex. Saline solution in your blood.
Lesson Overview
Cell Transport
Osmotic Pressure in Animals Cells
The net movement of water into or out of a cell exerts a force known as
osmotic pressure.
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Cell Transport
Osmotic Pressure in Plant Cells
Lesson Overview
Cell Transport
Active Transport (Requires Energy)
The movement of material against a concentration gradient is known as active
transport. Active transport requires energy!!!!
- Uses protein pumps and ATP to pump
materials across the membrane.
Lesson Overview
Cell Transport
Bulk Transport (Requires Energy)
Endocytosis = taking material into
the cell with vesicles using the cell
membrane.
Exocytosis = vesicles fuse with
the membrane and push the
contents out of the cell.
BOTH REQUIRE ENERGY!!!