Cell Transport Notes
_________________ – When the particles of one substance are uniformly
distributed in another substance.
___________________ – A substance that can dissolve another substance.
___________________ – A substance that is dissolved in a solvent.
Molecular Movement
All the substances important to life are usually part of a solution.
The solvent makes up the ______________________ of this solution.
(REMEMBER: the substance dissolved in the solvent is the solute.)
________________________ is the solvent of most solutions involved in cellular
activities.
Molecules of matter are in constant motion.
In liquids and gasses, molecular motion is ____________________________.
The constant random movement of molecules is
_______________________________________.
Diffusion
______________________ is the process by which molecules of a substance move
from areas of _______________ concentration to areas of ______________
concentrations. (Ex: movement of materials in and out of a cell across the
membrane.)
The diffusion of water is called __________________.
When describing diffusion into and out of a cell or organelle, the movement of
molecules occurs across a ___________________________________________
The difference in the concentration of molecules from the highest concentration to
the lowest concentration is the _______________________
Factors Affecting Diffusion Rate
1. concentration
(higher = ____________________)
2. _________________________________
3. pressure
(warmer = faster)
(__________________________________ = faster)
Diffusion Across Membranes
Characteristics of Cell Membranes
 Cell membranes are selectively permeable, which means that they only
allow certain things to enter and leave the cell.
The cell membrane is composed of:
1. Two layers of _______________________________
2. Proteins
3. __________________________________
4. Carbohydrate chains
Fluid Mosaic Model
 Lipids are fluid so some of the proteins move about within the lipid layers.
Osmosis and Living Cells
_________________________ is the diffusion of water across a selectively
permeable membrane.
 Water makes up 70-95% of a living cell, so osmosis is a very important
transport mechanism.
 The cell has ______________________ over osmosis.
 Water will move in and out until the concentration is equal on both sides of
the _______________
Types of Solutions
Isotonic Solution = the concentration of solutes outside of the cell is
_____________________________of the cell.
Ex: Red blood cell placed in an isotonic solution would ___________________ in
size.
Hypotonic Solution = the concentration of solutes outside the cell
____________________ inside of the cell.
Ex: Red blood cell placed in a hypotonic solution would
__________________.
Hypertonic Solution = The concentration of solutes outside the cell
____________________ inside of the cell.
Ex: Red blood cell placed in a hypertonic solution would
___________________.
“iso” = equal
“hypo” = less than
“hyper” = more than
Other means of transport: Osmosis and diffusion are __________________
_________________
because they do not use any energy to move materials across the membrane.
-Sometimes movement of materials requires assistance from the cell or needs
energy. (2 types)
Carrier and channel proteins- part of the cell membrane and transport
____________ molecules that cannot dissolve in the lipids of the cell membrane,
IF:
NO Energy is required called Facilitated diffusion-substances move with the
concentration gradient
from high to low, but carrier molecules ___________ ______ the movement of
diffusing substances.
ENERGY IS REQUIRED is called ________________ _______________, the
movement of materials from low to high across the concentration gradient.