Tuesday 12/6
Warm-Up: What is the function of the plasma membrane?
What is the function of proteins in the plasma membrane?
Agenda:
• Notes on Diffusion
• Demo: Perfume & Diffusion
• Demo: Affect of Temperature on Diffusion
• Diffusion Worksheet
Monday 12/12
Warm-Up: Hand-Out (MCAS Open Response Question)
Agenda:
• Plasma Membrane Review Sheet
• Quiz
• Notes: What is Diffusion?
• Demo: Perfume & Diffusion
• Diffusion Worksheet
Monday 11/19 (period 5/6)
Warm-Up: What is the function of the carbohydrate in
the cell membrane? What is the function of the
cholesterol in the cell membrane?
Agenda:
• Hand in HW (Plasma Membrane Practice) into INBOX
• Demo: Perfume & Diffusion
• Notes: What is Diffusion?
• Diffusion Worksheet
• Go over Tests
HW: Diffusion Chart WS
Wednesday 11/28 (period 10)
Warm-Up: What are the 4 structures in the cell
membrane?
Agenda:
• Go over HW (Plasma Membrane Practice WS)
• Notes: What is Diffusion?
• Diffusion Worksheet
Diffusion
Transport in Cells
• In order for cells to maintain homeostasis, they must have
a way of moving substances through the cell membrane.
• The cell membrane controls movement of dissolved
molecules from the solution on one side of the cell
membrane to the solution on the other side.
• The concentration of a solution is the amount of solute in a
liquid (solvent). HIGH concentration means LOTS of solute.
•There are two kinds of ways that the cell controls solute
concentration in cells: passive and active transport.
CELL TRANSPORT: Two
types
PASSIVE
• Does not use
energy
ACTIVE
• Uses cell’s energy
ATP
• Molecules move
from high conc. to
low
• Molecules move
from low to high
conc.
• Movement is along
the conc. gradient
• Movement is
against the conc.
gradient
PASSIVE TRANSPORT
1. Diffusion
2. Facilitated diffusion
3. Osmosis
Passive Transport: Diffusion
• In diffusion, molecules move from an area of higher
concentration to an area of lower concentration.
• The solute particles will continue to move until equilibrium
is reached (same amount of solutes on both sides of the
membrane).
Diffusion Through Cell Boundaries
Solutes always move DOWN their concentration
gradient (from high to low concentration). Even solutes
want some space for themselves!
Diffusion Through Cell Boundaries
When equilibrium is
reached (same amount of
solutes on both sides),
solute particles continue to
diffuse across the
membrane in both
directions.
Rate of Diffusion
• 3 factors affect how fast diffusion occurs:
– Concentration: diffusion is faster at higher
concentrations
– Temperature: diffusion is faster at higher
temperatures
– Pressure: diffusion is faster at higher pressures
Molecules that can diffuse….
• Small lipids
• Nonpolar molecules like…
– Carbon dioxide
– Oxygen
Why are these important??
Passive Transport:
Facilitated Diffusion
Glucose
molecules
• Facilitated diffusion is
when molecules move
across the cell
membrane from HIGH to
LOW concentration
using the help of a
protein to act as a
Protein
channel
channel for the solute to
pass through the
membrane.
Passive Transport: Facilitated Diffusion
Channel Proteins
• open and close to allow
substances to diffuse
through the plasma
membrane
Carrier Proteins
• change shape to help
move particles through
the membrane
Passive Transport: Facilitated Diffusion
Glucose
molecules
• Facilitated diffusion is
needed for molecules
that are too big to move
through the lipid bilayer
on their own.
Glucose
protein
channel
•Each facilitator protein
is specific to each kind of
molecule (for example,
glucose can only go
through glucose
facilitator proteins).
Passive Transport: Osmosis
• In osmosis, water diffuses through a selectively
permeable membrane.
• When a membrane is selectively permeable, it means
that only certain things can pass through it (like water or
very small ions/solutes). If it is NOT permeable to a solute,
that solute can NOT get through.
Passive Transport: Osmosis
• When a cell is in a solution, that solution may be
hypertonic, hypotonic, or isotonic to the cell.
• Hypertonic- when a solution has a higher
concentration of solutes (and less water) than the
cell
• Hypotonic- when a solution has a lower
concentration of solutes (and more water) than the
cell.
• Isotonic- when a solution has the same
concentration of solutes as the cell.
Isotonic solution
H2O
Hypotonic solution
Hypertonic solution
H2O
H2O
H2O
Animal
cell
(2) Lysed
(1) Normal
H2O
H2O
(3) Shriveled
Plasma
membrane
H2O
H2O
Plant
cell
(4) Normal
In an isotonic
solution, a cell stays
normal
(5) Turgid
(6) Shriveled
(wilted)
In a hypotonic solution, a In a hypertonic solution, a
cell gets very big and
cell shrivels up
swells
Draw a cell in a hypertonic environment
Which way will
the water
travel?
= solute
molecule
Into the cell
Cell
Out of the cell
Beaker of
Solution
22
Draw a cell in a hypotonic environment
Which way will
the water
travel?
Out of the cell
= solute
molecule
Cell
Into the cell
Beaker of
Solution
23
Draw a cell in an isotonic environment
Which way will
the water
travel?
= solute
molecule
No net mvmt.
Cell
No net mvmt.
Beaker of
Solution
24
Cell Transport - Diffusion
Transport in Cells
• In order for cells to maintain homeostasis, they must have
a way of moving substances through the cell membrane.
• The cell membrane controls movement of dissolved
molecules from the solution on one side of the cell
membrane ________________________________________.
• The concentration of a solution is the amount of solute in a
liquid (solvent). HIGH concentration means LOTS of solute.
•There are _______________________that the cell controls
solute concentration in cells: passive and active transport.
CELL TRANSPORT: Two
types
PASSIVE
ACTIVE
PASSIVE TRANSPORT
1. Diffusion
2. Facilitated diffusion
3. Osmosis
Passive Transport: Diffusion
• _________________, molecules move from an area of
higher concentration to an area of lower concentration.
• The solute particles ____________________________until
equilibrium is reached (same amount of solutes on both
sides of the membrane).
Diffusion Through Cell Boundaries
Solutes always move DOWN their concentration
gradient (from high to low concentration).
_____________________
Diffusion Through Cell Boundaries
There is a higher
concentration of solute
on one side of the
membrane as
______________________
______________________
______________________
Diffusion Through Cell Boundaries
Solute particles move from the
side of the membrane with a
higher concentration of solute
to the side of the membrane
with a lower concentration of
solute (HIGH  LOW). The
solute particle ______________
_________________________
_________________________
__
until equilibrium is reached.
Diffusion Through Cell Boundaries
When equilibrium is
reached (same amount of
solutes on both sides),
______________________
______________________
______________________
______________________
in both directions.
Rate of Diffusion
• 3 factors affect how fast diffusion occurs:
– ______________________: diffusion is faster at
higher concentrations
– ______________________: diffusion is faster at
higher temperatures
– ______________________: diffusion is faster at
higher pressures
Molecules that can diffuse….
Why are these important??
Passive Transport: Facilitated Diffusion
Glucose
molecules
• Facilitated diffusion is
when molecules move
across the cell
membrane from ______
____________________
____________________
using the help of a
Protein
protein to act as a
channel
channel for the solute to
pass through the
membrane.
Passive Transport: Facilitated Diffusion
Channel Proteins
• ___________________
____________to allow
substances to diffuse
through the plasma
membrane
Carrier Proteins
• _____________________t
o help move particles
through the membrane
Passive Transport: Facilitated Diffusion
Glucose
molecules
• Facilitated diffusion is
needed for molecules
that are too big to move
through the __________
____________________.
Glucose
protein
channel
•Each facilitator protein
is specific to each kind of
molecule (for example,
glucose can only go
through glucose
facilitator proteins).
Passive Transport: Osmosis
• In osmosis, water diffuses through a selectively
permeable membrane.
• When a membrane is selectively permeable, it means
that only certain things can pass through it (__________
_____________________________). If it is NOT
permeable to a solute, that solute can NOT get through.
Passive Transport: Osmosis
• When a cell is in a solution, ___________________
hypertonic, hypotonic, or isotonic to the cell.
• Hypertonic- when a solution has a higher
concentration of solutes (____________________)
than the cell
• Hypotonic- when a solution has a lower
concentration of solutes (____________________)
than the cell.
• Isotonic- when a solution has the same
concentration of solutes as the cell.
Isotonic solution
H2O
Hypotonic solution
Hypertonic solution
H2O
H2O
H2O
Animal
cell
(2) Lysed
(1) Normal
H2O
H2O
(3) Shriveled
Plasma
membrane
H2O
H2O
Plant
cell
(4) Normal
In an isotonic
solution, a cell stays
normal
(5) Turgid
(6) Shriveled
(wilted)
In a hypotonic solution, a In a hypertonic solution, a
cell gets very big and
cell shrivels up
swells
Draw a cell in a hypertonic environment
Which way will
the water
travel?
= solute
molecule
Into the cell
Cell
Out of the cell
Beaker of
Solution
43
Draw a cell in a hypotonic environment
Which way will
the water
travel?
Out of the cell
= solute
molecule
Cell
Into the cell
Beaker of
Solution
44
Draw a cell in an isotonic environment
Which way will
the water
travel?
= solute
molecule
No net mvmt.
Cell
No net mvmt.
Beaker of
Solution
45