Cell Transport
Past learning: What is the
function of the cell
membrane?
Cyclosis: the streaming of
cytoplasm
DIFFUSION
• The movement of molecules from an area
of high concentration to an area of low
concentration without using cell energy
• Examples:
• The smell of perfume through a room
• Sugar in coffee
• Food coloring in water
In which cell is diffusion occurring?
B
How do you know?
Molecules are moving from high to
low
In which direction will these
molecules diffuse?
Why do molecules move
from high concentration to low
concentration?
•All molecules are always in motion.
• The higher the temperature, the faster they move.
Brownian Motion
Robert Brown observed
particles inside of
vacuoles vibrating. He
stated that ALL particles
are moving ALL the
time.
Not to be confused with
Brownie in Motion
Diffusion
Factors that affect Diffusion
• Concentration – greater concentrations
results in more rapid diffusion
• Temperature: greater temperature results
in greater speed of molecules
Facilitated Diffusion
• Molecules move rapidly across the cell
membrane through a transport protein
Equilibrium
• Equilibrium is reached when molecules
are evenly distributed
Into the cell or Out of the cell?
Out of the cell.
Into the cell.
Equilibrium is reached.
Osmosis
• Diffusion of water through a membrane
Concentration Gradient
• The difference in concentration between
an area of greater concentration and one
of lesser concentration
• Diffusion occurs whenever there is a
concentration gradient
Passive Transport
• Process by which materials move across
the cell membrane without the expenditure
of cellular energy
• Examples: Osmosis and Diffusion
Active Transport
• The process by which materials move
across the cell membrane with the
expenditure of cellular energy
• This allows the cell to be chemically
different from it’s surroundings
• Moves molecules from low concentration
to high concentration
• Examples: phagocytosis,pinocytosis and
endocytosis
• In which cell is active transport taking
place?
• Cell A
• Is energy required?
• Yes!!!
Isotonic solution
• Contains the same concentration of
dissolved substances as the cell placed in it
Hypotonic Solution
• Contains a lower concentration of
dissolved substances than the cell
– Water is more concentrated outside
– Animal cells swell and burst
– Plant cells excess water is collcted inside the
vacuole
Hypertonic Solution
• Has a higher concentration of dissolved
substances than the cell
– Water is more concentrated on the inside
– Animal cells shrink
– Plant cells the vacuole will collapse and the
cytoplasm will shrink
• Iso
hypo
hyper