CELL TRANSPORT
MODULE
ASHLEY J. TAYLOR
MVHS Science Department
M
V
H
S
CELL MEMBRANE
A semi-permeable barrier made up of a
double layer of phospholipids that monitors
the passage of materials in and out of the
cell.
Source: Nowicki, S. (2008). Chapter 3: Cells. In McDougal Littell Biology (pp. 82). Evanston, IL: McDougal Littell
MOVEMENT ACROSS MEMBRANE
Important Terms
• Concentration is the number of molecules of a
substance in a given volume.
• Concentration gradient is the difference in the
concentration of a substance from one location to
another.
Materials move across membranes because of
concentration differences.
PASSIVE TRANSPORT
Passive transport is the movement of molecules
across the membrane from areas of higher
concentration to areas of lower concentration.
It does not require energy input from the cell.
Three Types of Passive Transport
Diffusion
Osmosis
Facilitated
Diffusion
TYPES OF PASSIVE TRANSPORT
Diffusion
movement of
molecules from
areas of higher
concentration to
areas of lower
concentration
Osmosis
movement
from high
to low
movement of
water from areas
of higher
concentration to
areas of lower
concentration
Movement of molecules across a
membrane through transport proteins
Facilitated Diffusion
PASSIVE TRANSPORT ANIMATIONS
ACTIVE TRANSPORT
Active Transport occurs when a cell uses energy to
move molecules against a concentration gradient.
Molecules are moved from lower to higher
concentration.
It does require energy input from the cell.
Types of Active Transport
Endocytosis
Exocytosis
SodiumPotassium
Pump
TYPES OF ACTIVE TRANSPORT
Endocytosis
Exocytosis
“Cell Eating”
the opposite of
endocytosis
removal
of substances
out of a cell by
the fusion of a
vesicle with the
membrane.
cell
membrane
engulfs a
substance
and brings it
inside the
cell
ENERGY
REQUIRED
LOW - HIGH
Sodium-Potassium Pump
Movement of Na+ and K+ ions across a membrane
through the use of a pump.
Requires Energy in the form of ATP & a Carrier Protein
ACTIVE TRANSPORT ANIMATIONS
UNDERSTANDING CHECK
Na+ K+ Pump
Energy Required
Source: Shuster, et al., Biology for a Changing World, First Edition, W. H. Freeman & Co.
© 2012 W. H. Freeman & Co. and Sumanas, Inc.
REINFORCEMENT ACTIVITY
Cell Transport Puzzles
Please complete the following Cell Transport Puzzles
Double clicking on the puzzle will open the PDF file and allow printing.
Puzzles generated and provided by USATest Prep
SOURCES
Nowicki, S. (2008). Chapter 3: Cells. In McDougal
Littell Biology (pp. 70-84). Evanston, IL: McDougal
Littell
Shuster, et al., Biology for a Changing World, First
Edition, W. H. Freeman & Co.
© 2012 W. H. Freeman & Co. and Sumanas, Inc.