3/30 Daily Catalyst Pg. 42 Passive transport
 1. Compare the contrast eukaryotes and
prokaryotes.
 2. If a molecule is a small hydrophobic molecule,
predict if it will pass through the bilayer.
 3. If the cell membrane is lacking a properly folded
protein, what organelle malfunctioned?
3/30 Daily Catalyst Pg. 42 Passive transport
 Quiz #10 on Wednesday
 Cell and Transport test on Wednesday
 Review day on Tuesday
 M.C. on cells and transport
 Tutoring available
 Spring Break review packet due Tuesday, April 7th
 Test corrections due TOMORROW
3/30 Daily Catalyst Pg. 42 Passive transport
 Daily Catalyst
 Class Business
 Finish intro to transport
 Lab Prep
 Passive transport notes
 Homework: flip flop and test corrections
 Cell Review
3/30 Objective
 We will be able to compare and contrast
active and passive transport to…
Understand the importance of the both
types of transport and how they function
in the cell.
 Back to page 41
Cellular membranes are fluid mosaics of
lipids and proteins
 Key Point #5: The fluid mosaic model:
 A membrane is a fluid structure with a “mosaic” of various
proteins embedded in it
Protein Type #1
 Key Point #6: Integral proteins
 Transmembrane proteins
 spanning the membrane
EXTRACELLULAR
N-terminus SIDE
C-terminus
Figure 7.8
a Helix
CYTOPLASMIC
SIDE
Protein Type #2
 Key Point #7: Peripheral proteins
 Loosely bound to the surface of the membrane
 Act as an “appendage”
Membranes are fluid structures
 Membranes are not static sheets locked rigidly in place.
 Key Point #8: Held together by hydrophobic interactions
 Very weak
The Fluidity of Membranes
 Phospholipids in the plasma membrane
 Can move within the bilayer
Lateral movement
(~107 times per second)
(a) Movement of phospholipids
Flip-flop
(~ once per month)
Membranes are fluid structures
 Membranes are not static sheets locked rigidly in place.
 Key Point #8: Held together by hydrophobic interactions
 Very weak
Key Concepts
 1. Membrane structure results in selective permeability
 2. Cellular membranes are fluid mosaics of lipids and proteins
 3. Membranes are fluid structures
Lab Prep
 Directions: With your lab group, complete the following tasks.
STOP when I say STOP!




Read the scenario
Create your hypothesis
Read the background info and answer the question
STOP!
 Noise: 1 (with group)
 Time: 10 minutes
Lab Groups
1
2
3
4
5
6
7
8
Rilda
Christia Diana
n
Romel
Odalys
Sierra
Kyla
Kaitlyn
Joseph
Michell
e
Mario
Malika
Karina
Mr.
Kaki
Juliann
a
Moha
mmad
Tashto
ni
Hanna
h
Tiesha
Irma
Hanna
h O.
Lawren
Victoria Camila
Esteph
anie
Lavone Hanna
h L.
Savann Esther
ah
Chris R.
Lab Prep
 Directions: With your lab group, complete the following tasks.
STOP when I say STOP!




Read the scenario
Create your hypothesis
Read the background info and answer the question
STOP!
 Noise: 1 (with group)
 Time: 10 minutes
Lab Prep 2
 Directions:
 Noise: 1 (with group)
 Time: 12 minutes
Lab Prep
Red Rover
Review
The function of the cell membrane:
 is to allow only certain molecules in and out of
the cell.
REMEMBER THIS!
 The cell membrane is the “bouncer” of
the cell.
What does the cell membrane look
like?
Review
 Semi-permeable:
 Allows certain molecules to enter the cell
and other molecules are not allowed in.
Cell Transport
Passive
Active
Read and Respond
 Directions: Take 4 minutes to read the cell membrane
article silently and independently.
 Choose ONE and only ONE important fact from this
reading.
• Key Point #1:
–Passive Transport does not
require energy (ATP)
How does Febreze work?
Key Point #2:
 Key Point #2: In PT Molecules move across a membrane from high to
low concentrations.
Concentration Gradient
Key Point #3: Concentration Gradient
The __________
MOVEMENT of molecules in an
__________.
AREA
Diffusion is a type of Passive
Transport
 Key Point #4: Diffusion
 Is the tendency for molecules of any substance to spread out evenly into
the available space
(a) Diffusion of one solute. The membrane
has pores large enough for molecules
of dye to pass through. Random
movement of dye molecules will cause
some to pass through the pores; this
will happen more often on the side
with more molecules. The dye diffuses
from where it is more concentrated
to where it is less concentrated
(called diffusing down a concentration
gradient). This leads to a dynamic
equilibrium: The solute molecules
continue to cross the membrane,
but at equal rates in both directions.
Molecules of dye
Membrane (cross section)
Net diffusion
Net diffusion
Equilibrium
Diffusion
 Diffusion is a type of PASSIVE TRANSPORT
 This means….
 ATP (energy) is not used
 Molecules move from high to low concentration
 An example is Febreze
When will molecules stop moving?
…concentration is equal (EQUILIBRIUM)
Cell Review
 Put your notebook and materials away
 Homework: flip flop worksheet and test corrections