Page 93 - Science Course 1 (Book 1)

Mo3-L5a: How Does Material Enter and Leave Cells?

Endocytosis Diffusion
the process during which a cell takes in a substance Diffusion is the movement of substances from an
by surrounding it with the cell membrane. area of higher concentration to an area of lower
Outside the Cell concentration.

Inside the Cell a. Diffusion of one Solute

Exocytosis Water
the process during which a cell’s vesicles release
their contents outside the cell.

Outside the Cell
Membrane Equilibrium
Inside the Cell cross section
Molecules
of dye

b. Diffusion of two Solute

Let’s Begin

Passive Transport

Passive transport is the movement of substances
through a cell membrane without using the cell’s
energy.

Small molecules, such as oxygen and carbon
dioxide, pass through membranes via passive
transport.
Diffusion continues until the concentration of a
Passive transport depends on the amount of substance is the same on both sides of the
substance on each side of a membrane. membrane. The substance is then in equilibrium.

Outside Cell

Water

Net Diffusion Net Diffusion Equilibrium
Inside Cell

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