Transcript Chapter Two Section Two

Chapter Four Section One
Cell Transportation
Think!!
How is a cell like a space station?
1. How is the cell
1. It is selectively
membrane like a
permeable.
gatekeeper.
Allows some things
to pass
through; not
others
2. Materials can
move in and out
of a cell two
ways.
2. Passive Transport
–Diffusion
-Osmosis
Active Transport
-Endocytosis
-Exocytosis
3. What is
Passive
Transport?
3. Movement of
materials
through cell
membrane
WITHOUT using
energy.
3.
3. Like bicycling
downhill.
Diffusion and
Osmosis are
forms of passive
transport
4. What is
Diffusion?
4. SMALL
Molecules move
from a crowded
area to a less
crowded area.
Pencils Down!
Dye diffuses from a crowded (concentrated
area) to a less concentrated area. Ch 4 Fig 1.
Ch 4 Figure 2
100 % water
60 % water
5. Why does
diffusion
happen?
5. Molecules always
moving
More Molecules 
More Collisions 
More Pushing Away
from each other
•Small particles
•Crowded to less
crowded
•NO energy required
6. How do singlecelled organisms
get oxygen
inside?
6. More oxygen in
water than
inside cell.
Ch 4 Fig. 3
7. What is
Osmosis?
7. Diffusion of
water across a
cell membrane.
8. Why is osmosis
important to
cells?
8. Cells need water
to function.
Think
Why can some fish
live only in fresh
water and some
live only in
saltwater?
Think
Different
adaptations.
9. What is
Active
Transport?
9. Move materials
through cell
membrane using
energy.
From less
crowded area to
more crowded
area.
9. What is
Active
Transport?
9. Like pedaling
UP HILL!
10. How does active
transport happen?
2 ways:
10. FOR SMALL
PARTICLES:
Transport
proteins pick up
a molecule and
carry it across
the membrane.
Ch 4 Fig 3
•Small particles
•Less crowded to more
crowded
•ENERGY required
Chapter 4 Figure 3
10. How does active
transport happen?
2 ways:
10. FOR LARGE
PARTICLES:
Endocytosis:
membrane
surrounds molecule
and pinched off
into vacuole.
Ch 4 Fig 4
Chapter 4 Figure 4
10. How does
active transport
happen?
2 ways:
10. FOR LARGE
PARTICLES:
Exocytosis:
vesicle carries
particles to cell
membrane to
release
Ch 4 Fig 5
11. Why are cells
so small?
11. If too large,
it’s hard to move
material in and
out of the cell.
It is too far
from the
membrane.
Exit Slip
• Create a simple Venn Diagram to
compare active and passive transport.
Exit Slip
• A single-celled organism is
transferred from a tank of fresh
water into a tank of salt water. How
will the cell change? Explain.