Transcript Plasma Membrane

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Tuesday already!  10/6
Bellwork
1. Compare and contrast Prokaryotes and
Eukaryotes.
2. Compare and contrast plant and animal
cells
– You may use Venn Diagram to help in
making the comparison
Plan for today:
work on 7.1- 1 & 3; 7.2- 1, 4, & 5
Work on analogy…
…or finish notes
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Bellwork 10/8 Life is Good!
1. What are eukaryotes and give 4
examples?
2. Which is more complex --- prokaryotes
or eukaryotes?
3. Name the 3 basic parts of all
eukaryotic cells.
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Solution
Solution
Solution
Solution
A: Egg swells to about twice its original size.
B: Egg absorbs bright green color, but remains original size.
C: Egg shrivels to about half of its original size.
D: Egg remains largely unchanged.
A typical egg contains about 2% dissolved solids. Douglas places de-shelled
eggs in four unknown solutions provided by his biology teacher. Based on
this fact, predict which solution contains 10% saltwater, from the
observations of the egg.
A) Solution A
B)
Solution B
C)
Solution C
D)
Solution D
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Quiz—Please get out a piece of paper
and answer the following.
1. Make a sketch of a cell and label the following: cell
membrane, ribosomes, cytoplasm, vacuole, nucleus, and
mitochondria.
2. The cell membranes are made of a double layer
of_________ and _______. Make a sketch of this.
3. What are 3 types of cells with cell walls and what
makes up the cell wall of each of these.
4. What is the function of membrane proteins?
5. Where is the cell membrane in plants found?
6. If a cell membrane pulls away from the cell wall
whenever the cell loses water what happens to the
plant cell?
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Sponges, members of the phylum Porifera, are
sessile filter feeders that lack tissues or organs.
Instead, specialized cells have unique functions like
ingesting food, support, and reproduction. Such
specialization within a sponge body is a result of
A) cytokinesis.
B) cell cleavage.
C) cell differentiation.
D) gamete fertilization.
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Cell Analogy Project
Objectives
• Relate cell to familiar
object
• Demonstrate knowledge
of cells part by relating
to object or place
• Identify how cell part
play important roles in
cell
• Relate structures and
functions
HOW it will be graded
• 70 points from rough
drafts
• 7 drafts at 10 points each
• 1 sentences explaining
relationship = 2 points
• 2 sentences relating how
they function similarly= 4
points
• 2 sentences relating how
they have similar
structures= 4 points
Cell Analogy Project
Final draft 20points
• 5 points = typed one
sentences explaining the
relationship per paragraph
• 10 points = typed 2-3
sentences explaining the
relationship
• 15 points = typed 3-4
sentences explaining the
relationships
• 20 points= correct format 8
paragraph each having 5+
sentences explaining the
relationships includes
introduction
Presentation
• 5 point= reading analogy
from final
• 10 points= student uses
notecard s for
presentation on occasion
• 15 points= student looks at
audience and give
presentation occasionally
looking at notecards
• 20 points= student is
dress and gives
presentation with minimal
aid of notes
Cell analogy project
Visual aid (Bonus)
• 5 points = poster board
with small pictures of cell
parts or object
• 10 points = poster board
with pictures of both cell
parts and comparison
object
• 15 points= large visual aid
that is easy to read and
follow
• 20 points= student uses
color and organizes visual
aid to show relationships
Total project is worth 110
points
•
•
•
•
Rough drafts 70 points
Final version 20 points
Presentation 20 points
Visual aid (bonus) 20
points
• All students will have
different objects.
Example
Cell parts
• Mitochondria
• Cell membrane
• Nucleus
• Cytoplasm
• Ribosome
• Cell wall
• Chloroplast
Human body
• Digestive track
• Skin
• Skull
• Blood
• Nerves
• Bones
• Fat cells
Cell Analogy Project—Due Monday
• Format:
• 1: The first sentence should describe the
analogy, for example, mitochondria is like the
furnace in a house.
• 2-4: The second, third, and fourth sentences
should describe that specific part of the cell in
scientific terms.
• 5-6: The fifth and sixth sentences should
describe that specific part of the
analogy.
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The Plasma Membrane -
Gateway to the Cell
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Photograph of a Cell
Membrane
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Cell Membrane
The cell
membrane is
flexible and
allows a
unicellular
organism to
move
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Homeostasis
• Balanced internal condition of
cells
• Also called equilibrium
• Maintained by plasma membrane
controlling what enters & leaves
the cell
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Functions of Plasma
Membrane
 Protective barrier
 Regulate transport in & out of cell
(selectively permeable)
 Allow cell recognition
 Provide anchoring sites for filaments
of cytoskeleton
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Functions of Plasma
Membrane
 Provide a binding site for enzymes
 Interlocking surfaces bind cells
together (junctions)
Contains the cytoplasm (fluid in cell)
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Structure of the Cell
Membrane
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Membrane Components
Phospholipids
Cholesterol
Proteins
(peripheral and integral)
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Carbohydrates (glucose)
Phospholipids
Make up the cell
membrane
Contains 2 fatty
acid chains that
are nonpolar
Head is polar &
contains a –PO4
group &
glycerol
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Bellwork 10/13 Good Tuesday to you 
• Using the concept of osmosis, explain why water is
sprayed over produce in a grocery store. How might
this change the appearance of the produce, and why
would this change be desirable? Use the principles of
osmosis to explain what happened.
• Turn in bellwork when finished.
• Find your poster (if you made one) be sure your
name is on it!!!!
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Which box depicts the tissue level of organization?
A) P
B) Q
C) R
D) S
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Homework during break
• Homework during break: Read over
Chapter 7 and study it outline study the
highlighted words.
1. Complete 7.3 and 7.4—all questions.
2. Describe an experiment of your choice and
identify the IV, DV & Control
• Know: Osmosis, diffusion, selectively
permeable, the organelles of a cell,
Scientific Method; IV, DV, and Control
of an experiment, safety in the lab,
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and lab tools,
FLUID MOSAIC MODEL
FLUID- because individual phospholipids and
proteins can move around freely within the
layer, like it’s a liquid.
MOSAIC- because of the pattern produced by
the scattered protein molecules when the
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membrane is viewed from above.
Cell Membrane
Polar heads are hydrophilic “water loving”
Nonpolar tails are hydrophobic “water fearing”
Makes membrane “Selective” in what crosses26
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Semipermeable Membrane
Small molecules and larger hydrophobic
molecules move through easily.
e.g. O2, CO2, H2O
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Semipermeable Membrane
Ions, hydrophilic molecules larger than
water, and large molecules such as proteins
do not move through the membrane on their
own.
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Figure 5.10
Lower
concentration
of solute (sugar)
Higher
concentration
of solute
Sugar
molecule
H2O
Selectively
permeable
membrane
Osmosis
More similar concentrations of solute
Bellwork 10/19 Good Day to you 
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Figure 5.10a
Lower
concentration
of solute (sugar)
Higher
concentration
of solute
Sugar
molecule
H2O
Predict what you think will happen to
the water levels on either side of
the semi permeable membrane.
Figure 5.10a
Lower
concentration
of solute (sugar)
Higher
concentration
of solute
More similar concentrations of solute
Sugar
molecule
hypotonic
H2O
hypertonic
isotonic
The Plan 
• USATestprep 3 assignments 2 due Wed,
the last due Friday. EC if completed by tomorrow for the first two.
• Benchmark Wed. Need to know:
– Safety in the lab
– Experimental design
– Hierarchy/organization (atom, molecules,
cells, etc.
– Prokaryotes Vs. Eukaryotes
– Bacteria vs Plant vs animal vs fungal vs
protist
– Cells—organelles, cell membrane and
transport— osmosis hypo, hyper and
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isotonic
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Simple Diffusion
• Requires NO
energy
• Molecules
move from
area of HIGH
to LOW
concentration
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DIFFUSION
Diffusion is a
PASSIVE process
which means no
energy is used to
make the
molecules move,
they have a
natural KINETIC
ENERGY
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Diffusion of Liquids
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Diffusion through a
Membrane
Cell membrane
Solute moves DOWN concentration gradient (HIGH to
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LOW)
Osmosis
• Diffusion of water
across a
membrane
• Moves from HIGH
water potential
(low solute) to
LOW water
potential (high
solute)
Diffusion across a membrane
Semipermeable
membrane
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Diffusion of H2O Across A
Membrane
High H2O potential
Low solute concentration
Low H2O potential
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High solute concentration
Aquaporins
• Water Channels
• Protein pores used during
OSMOSIS
WATER
MOLECULES
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Bellwork 10/20
• Sketch a picture of a cell in an
isotonic, hypotonic and hypertonic
environment and show the direction
of water movement.
• Don’t forget do the USATestprep
assignments—by midnight tonight, EC
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Benchmark test tomorrow
•
•
•
•
Review your notes—qual vs quantatative
Review Chapters 1, 2, & 7 in your book
Will count as a grade.
Tropism—
– Photo, geo, thigmo, hydro
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Cell in Isotonic Solution
10% NaCL
90% H2O
ENVIRONMENT
CELL
10% NaCL
90% H2O
NO NET
MOVEMENT
What is the direction of water movement?
equilibrium
The cell is at _______________.
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Cell in Hypotonic Solution
10% NaCL
90% H2O
CELL
20% NaCL
80% H2O
What is the direction of water movement?
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Cell in Hypertonic Solution
15% NaCL
85% H2O
ENVIRONMENT
CELL
5% NaCL
95% H2O
What is the direction of water movement?
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Cells in Solutions
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Bellwork 10/22
• Please answer all parts of
question #2 on page 213.
Transport
•
•
•
•
•
Active
Facilitated diffusion
Hypertonic, hypotonic, isotonic
Oxygen, CO2
Osmosis
• Proteins and ATP
• Na/K Pump
• Endocytosis
&Exocytosis
• Passive
• Glucose transport
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Benchmark
• You may retake the benchmark on
your own time. This will be another
grade in the grade book or an average
of the two.
• Here is your code: JANAROZOXE
• You will have until 10/29 to retake it.
After that time your original score
will replace the retake score.
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Plan
• Tomorrow— Chapter 7 test.
• If you want to do well: Reread the
chapter, take notes, study those
notes rewrite the assessment
questions read the back of the
chapter review—do the chapter
review. It is not a secret!
• PPT notes online to finish up…
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Isotonic Solution
NO NET
MOVEMENT OF
H2O (equal amounts
entering & leaving)
Hypotonic
Solution
CYTOLYSIS
Hypertonic
Solution
PLASMOLYSIS
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Cytolysis & Plasmolysis
Cytolysis
Plasmolysis
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Osmosis in Red Blood Cells
Isotonic
Hypotonic
Hypertonic
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hypotonic
hypertonic
isotonic
hypertonic
isotonic
hypotonic
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Three Forms of Transport Across the Membrane
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Passive Transport
Simple Diffusion
 Doesn’t require energy
 Moves high to low
concentration
 Example: Oxygen or
water diffusing into a
cell and carbon dioxide
diffusing out.
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Passive Transport
Facilitated diffusion
Doesn’t require energy
Uses transport
proteins to move high to
low concentration
Examples: Glucose or
amino acids moving from
blood into a cell.
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Types of Transport Proteins
• Channel proteins are embedded
in the cell membrane & have a
pore for materials to cross
• Carrier proteins can change
shape to move material from
one side of the membrane to
the other
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Facilitated Diffusion
Molecules will randomly move through
the pores in Channel Proteins.
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Facilitated Diffusion
• Some Carrier
proteins do not
extend through
the membrane.
• They bond and
drag molecules
through the lipid
bilayer and
release them on
the opposite side.
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Carrier Proteins
• Other carrier
proteins
change shape
to move
materials
across the cell
membrane
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Active Transport
Requires energy or
ATP
Moves materials from
LOW to HIGH
concentration
AGAINST
concentration gradient
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Active transport
Examples: Pumping
Na+ (sodium ions)
out and K+
(potassium ions) in
against strong
concentration
gradients.
Called Na+-K+ Pump
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Sodium-Potassium Pump
3 Na+ pumped in for every 2 K+ pumped
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out; creates a membrane potential
Moving the “Big Stuff”
Exocytosis
- moving
things
out.
Molecules are moved out of the cell by vesicles that fuse
with the plasma membrane.
This is how many hormones are secreted and how nerve
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cells communicate with one another.
Exocytosis
Exocytic
vesicle
immediately
after fusion
with plasma
membrane.
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Moving the “Big Stuff”
Large molecules move materials into the cell by
one of three forms of endocytosis.
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Pinocytosis
Most common form of endocytosis.
Takes in dissolved molecules as a vesicle
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Pinocytosis
• Cell forms an
invagination
• Materials
dissolve in
water to be
brought into cell
• Called “Cell
Drinking”
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Example of Pinocytosis
pinocytic vesicles forming
mature transport vesicle
Transport across a capillary cell (blue).
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Receptor-Mediated Endocytosis
Some integral proteins have receptors
on their surface to recognize & take in
hormones, cholesterol, etc.
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Receptor-Mediated Endocytosis
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Endocytosis – Phagocytosis
Used to engulf large particles such as
food, bacteria, etc. into vesicles
Called “Cell Eating”
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Phagocytosis About to Occur
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Phagocytosis
- Capture
of a Yeast
Cell (yellow)
by
Membrane
Extensions
of an
Immune
System Cell
(blue)
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Exocytosis
The opposite of endocytosis is exocytosis. Large
molecules that are manufactured in the cell are
released through the cell membrane.
Inside Cell
Cell environment
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