Transcript 08 Cellular Transport Student

10/13/15
Bellwork
• Add the following prefixes to your sheet:
iso—
hypo—
hyper—
endo—
Intra—
exo—
extra—
equal
low
high
inside
inside
outside
outside
Add these to your pre/suffix sheet
cyto –
—lysis
cells
break down
Bell work—write your responses on
a piece of paper and be ready to
discuss
Figure A
1. How do the plant
cells in figures A and
B differ?
2. What is the effect
of this difference on
the plants?
Figure B
3. After eating a sugary or salty snack, why are
you so thirsty?
The Life of a Cell
Cellular Transport and the Cell Cycle
Cellular Transport
Osmosis: Diffusion of Water
• Osmosis: The diffusion
of water across a
selectively permeable
membrane
• Regulating the water flow
through the plasma
membrane is an important
factor in maintaining
homeostasis within a cell.
What controls osmosis?
• Unequal
distribution of
particles, called
a concentration
gradient, is one
factor that
controls
osmosis.
Before
Osmosis
Selectively
permeable
membrane
After
Osmosis
Water molecule
Sugar molecule
Cells in an isotonic solution
H2O
H2O
Water Molecule
Dissolved Molecule
• Most cells are
surrounded by
water solutions.
http://highered.mheducation.com/sites/00724
95855/student_view0/chapter2/animation__h
ow_osmosis_works.html
Cells in an isotonic solution
• In an isotonic solution,
the concentration of
dissolved substances in
the solution is the same
as the concentration of
dissolved substances
inside the cell.
H 2O
H2O
Water Molecule
Dissolved Molecule
Cells in an isotonic solution
• In an isotonic
solution, water
molecules move
into and out of
the cell at the
same rate, and
cells retain their
normal shape.
H2O
H2O
Water Molecule
Dissolved Molecule
Cells in an isotonic solution
• A plant cell
has its
normal
shape and
pressure in
an isotonic
solution.
Cells in a hypotonic solution
• In a hypotonic
solution the
concentration of
dissolved
substances is
lower in the
solution outside
the cell than the
concentration in
the cell.
H2O
H2O
Water Molecule
Dissolved Molecule
Cells in a hypotonic solution
• Water enters a cell by
osmosis, increasing cell
pressure (called turgor
pressure) and causing the
cell to swell.
• Plant cells swell beyond
their normal size as
pressure increases.
Cells in a hypertonic
solution
• In a hypertonic
solution the
concentration of
dissolved
substances outside
the cell is higher
than the
concentration
inside the cell.
H2O
H2O
Water Molecule
Dissolved Molecule
Cells in a hypertonic solution
• Water leaves a cell
by osmosis, causing
the cell to shrink.
• Plant cells lose
pressure as the
plasma membrane
shrinks away from
the cell wall.
Bellwork
10/20
Fill in the blanks:
You decide to buy a new fish for your freshwater
aquarium. When you introduce the fish in its
new tank, the fish swells up and dies. You later
learn that the fish was from the ocean. Based on
what you know of tonicity, the most likely
explanation is that unfortunately the fish went
from a(n) ____ solution into a(n) _____
solution.
Cellular Transport Foldable
Hypotonic Solution
Isotonic Solution
Hypertonic Solution
How osmosis affects cells in…
Draw a picture of a cell
In a hypotonic solution
Inside front flap
5 points
Under flap
Hypotonic Solution—
Use your notes to
describe the effect
hypotonic solutions
have on cells
Isotonic Solution
Hypertonic Solution
5 points
How osmosis affects cells in…
30 Points Total
Passive Transport
• Passive transport: movement of materials
through a membrane that does not require the
cell to use energy
• Facilitated diffusion: the passive transport of
materials across the membrane using
transport proteins.
Passive Transport
• Some of the proteins form channels for the molecules to
flow through with the concentration gradient.
• Carrier proteins change shape to allow a substance to pass
through with the concentration gradient.
Active Transport
• Active transport: movement of materials through
a membrane against a concentration gradient that
requires energy from the cell
Carrier
proteins
Plasma
membrane
Concentration
gradient
Cellular
energy
Step 1
Step 2
Transport of Large Particles
• Endocytosis: a process by which a cell
surrounds and takes in material from its
environment.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• The material is engulfed and enclosed by a
portion of the cell’s plasma membrane.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• The resulting vacuole with its contents
moves to the inside of the cell.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• Exocytosis: the expulsion or secretion of
materials from a cell.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• Endocytosis and exocytosis both move
masses of material and both require energy.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis