Lesson #4: Passive Transport Flashcards
(8 cards)
Passive
Transport
Methods of transporting materials
into and out of cells that DO NOT
require energy
There are 3 types of passive transport:
- Diffusion
- Osmosis
- Facilitated Diffusion
Diffusion
The movement of molecules from an area of
high concentration to an area of lower
concentration (along a concentration
gradient).Oxygen and carbon
dioxide are able to
diffuse freely through a
semi - permeable
membrane.
If the size of a
molecule is small
enough it can diffuse
into and out of the cell.
Osmosis
The movement of WATER
from an area of high
concentration to an area
of low concentration
(along a concentration
gradient).
The Hypotonic
Environment
When placed in an
environment where the
concentration of solute is
less than the concentration
of solute inside the cell,
water will move into the
cell.
This environment is
referred to as Hypotonic.
The end result is often lysis
of the cell (the cell bursts)
The Hypertonic
Environment
When placed in an
environment where the
concentration of solute is
greater than the
concentration of solute
inside the cell, water will
move out of the cell.
This environment is
referred to as Hypertonic.
The end result is the
shrinking of the cell.
The Isotonic
Environment
When placed in an
environment where the
concentration of solute is
the same as the
concentration of solute
inside the cell the net
movement of water will be
zero.
This is the ideal
environment for the cell.
Facilitated
Diffusion
The movement of larger molecules
across the cell membrane with the
help of integral transport proteins.
Diffusion still follows the
concentration gradient (movement is
from an area of high concentration to
an area of low concentration).
Types of Facilitated Diffusion
Channel Mediated –
mostly ions selected by
size and charge.
Carrier Mediated –
specific to one
chemical, the binding
of the substrate causes
a shape change in the
transport protein.
