1

Do Now:Do Now:

How is a window screen similar to a cellHow is a window screen similar to a cell

membrane?membrane?1.1. What are some things that can pass through a What are some things that can pass through a

window screen?window screen?

2.2. What are some things that cannot pass What are some things that cannot pass through a window screen?through a window screen?

3.3. The cell is surrounded by a cell membrane, The cell is surrounded by a cell membrane, which regulates what enters and leaves the which regulates what enters and leaves the cell. Why is it important to regulate what cell. Why is it important to regulate what moves into and out of a cell?moves into and out of a cell?

Cell MembraneCell Membrane(Plasma Membrane)(Plasma Membrane)

Chapter 7: Section 7Chapter 7: Section 7--33

Electromagnetic energy

Label the DiagramLabel the Diagram In 1972, Singer and NicolsonIn 1972, Singer and Nicolson

Cell membrane Cell membrane -- made of scattered made of scattered

proteinsproteins and and lipidslipids that make up the that make up the

phospholipid bilayer. phospholipid bilayer.

Cell Membrane:Cell Membrane:Fluid Mosaic ModelFluid Mosaic Model

Fluid meaning movement.Fluid meaning movement.

�� Phospholipids movePhospholipids move

Figure 7.5 B

Fluid Viscous

Unsaturated hydrocarbontails with kinks

Saturated hydro-

Carbon tails

(b) Membrane fluidity

��Proteins can move (drift) inside the bilayerProteins can move (drift) inside the bilayer

EXPERIMENTResearchers labeled the plasma membrane proteins of a mouse

cell and a human cell with two different markers and fused the cells. Using a microscope, they observed the markers on the hybrid cell.

Membrane proteins

Mouse cell

Human cell

Hybrid cell

Mixedproteinsafter1 hour

RESULTS

CONCLUSIONThe mixing of the mouse and human membrane proteins

indicates that at least some membrane proteins move sideways within the plane of the plasma membrane.

+

2

Membrane Proteins and LipidsMembrane Proteins and Lipids

ER

Figure 7.10

Transmembraneglycoproteins

Secretoryprotein

Glycolipid

Golgiapparatus

Vesicle

Transmembraneglycoprotein

Membrane glycolipid

Plasma membrane:Cytoplasmic face

Extracellular face

Secretedprotein

4

1

2

3

�� Are synthesized Are synthesized

in the ER & Golgi in the ER & Golgi apparatusapparatus

Endoplasmic Reticulum Cell MembraneCell Membrane

Phospholipid Phospholipid

Bilayer

Hydrophilic

Hydrophobic

CholesterolCarbohydrate

Phospholipid

Phospholipid bilayer

Glycoprotein

Carrier Protein

Channel Protein

Receptor Protein

Starch

Cell MembraneCell Membrane

�� Flexible barrier made of special Flexible barrier made of special

properties to help maintain properties to help maintain

homeostasishomeostasis..

�� Made of phosphoMade of phospholipidslipids, ,

proteinsproteins, and , and carbohydratescarbohydrates

3 Parts of a3 Parts of aCell MembraneCell Membrane

1.1. PhospholipidPhospholipid -- a thin flexible sheet a thin flexible sheet arranged in a bilayer.arranged in a bilayer.

FunctionFunction: act as a : act as a barrierbarrier..

�� PhosphatePhosphate groupgroup

�� LipidsLipids-- fatty acid chainfatty acid chain

�� CholesterolCholesterol –– reduces fluidity (movement) in the reduces fluidity (movement) in the phospholipid area.phospholipid area.

Hydrophilic side (water loving) Hydrophilic side (water loving)

Hydrophobic side (water fearing)Hydrophobic side (water fearing)

2 Sides (Bilayer) 2.2. ProteinsProteins –– floats in the phospholipid floats in the phospholipid

layer.layer.

FunctionsFunctions::

�� Some Some transporttransport substances across the substances across the

membranemembrane

�� Others help with Others help with shapeshape

THINK OF AN ICEBERG!

3

3 Types of Proteins

1. Channel Proteins

2. Carrier Proteins

3. Receptor Proteins

3.3. CarbohydratesCarbohydrates (glucose) (glucose) –– attached attached

to proteins or the phospholipids.to proteins or the phospholipids.

FunctionFunction: help with cell : help with cell communicationcommunication

GlycoproteinsGlycoproteins

-- proteins with carbohydrates proteins with carbohydrates

attached.attached.

Think of an

antenna!

LET’S MAKE AN LET’S MAKE AN ANAL0GY!ANAL0GY!

THE CELL MEMBRANE THE CELL MEMBRANE

Protein FunctionsProtein Functions

http://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a1.htmhttp://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a1.htm

http://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a.htmhttp://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a.htm

www.ibiblio.org/virtualcell/textbook/chapter3/cmf3.htmwww.ibiblio.org/virtualcell/textbook/chapter3/cmf3.htm

http://www.teachersdomain.org/resource/tdc02.sci.life.cell.membraneweb/http://www.teachersdomain.org/resource/tdc02.sci.life.cell.membraneweb/

http://learn.genetics.utah.edu/content/begin/cells/insideacell/http://learn.genetics.utah.edu/content/begin/cells/insideacell/ (cell membrane)(cell membrane)

http://biohttp://bio--alive.com/animations/cellalive.com/animations/cell--biology.htmbiology.htm (library of websites)(library of websites)

http://www.wischttp://www.wisc--online.com/objects/index_tj.asp?objID=AP11604online.com/objects/index_tj.asp?objID=AP11604 (tutorial)(tutorial)

The Functions The Functions (Roles)(Roles)

For 3 Types of ProteinsFor 3 Types of Proteins

1. Channel Proteins1. Channel Proteins

�� Transports stuff! Transports stuff!

Ex) ions, moleculesEx) ions, molecules

http://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a1.htmhttp://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a1.htm

2. Carrier Proteins2. Carrier Proteins

�� Transports stuff!Transports stuff!

��Does not extend through the membrane. Does not extend through the membrane.

Bonds & drags molecules to release them Bonds & drags molecules to release them

on the other side.on the other side.

http://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a.htmhttp://www.ibiblio.org/virtualcell/textbook/chapter3/cmf1a.htm

4

3. Receptor Proteins3. Receptor Proteins

��Allows cell to communicate stuff!:Allows cell to communicate stuff!:

-- cell recognitioncell recognition

-- cell cell signalingsignaling

http://www.ibiblio.org/virtualcell/textbook/chapter3/cmf3.htmhttp://www.ibiblio.org/virtualcell/textbook/chapter3/cmf3.htm

ReviewReview::Constructing A Cell MembraneConstructing A Cell Membrane

http://www.wisc-online.com/objects/index_tj.asp?objid=AP1101

Cell MembraneCell Membrane

ConcentrationConcentration of substances are held of substances are held

constant to keep cell alive.constant to keep cell alive.

Cell MembraneCell Membrane

Selective PermeabilitySelective Permeability

Allows some chemicals to pass through Allows some chemicals to pass through more easily than others.more easily than others.

FactorsFactors AffectingAffectingMembrane PermeabilityMembrane Permeability

1. Size1. Size

Small Molecules Large Molecules

Water Starch

Oxygen Proteins

Glucose Lipids

Amino acids NaCl

Fatty Acids

Glycerol

Soluble end products

from digestion

5

Question #1Question #1

Do you think the Do you think the cell membranecell membrane will allow will allow

smaller molecules or larger molecules smaller molecules or larger molecules to pass to pass through without through without using energy? using energy?

2. Electrical Charge Molecules2. Electrical Charge Molecules

�� MoleculesMolecules = always = always neutralneutral charge (charge (STABLESTABLE))

�� IonsIons = (+, = (+, -- charge) (UNSTABLE)charge) (UNSTABLE)

H20 Molecules

QuestionQuestion

Do you think a cell membrane would Do you think a cell membrane would

allow allow stablestable or or unstableunstable molecules to molecules to enter without using energy?enter without using energy?

3. Type of permeability of that specific 3. Type of permeability of that specific

cellcell

Cell membrane

� Different cells have different types of membranes.

DiffusionDiffusion

ParticlesParticles move constantly, collide, & move constantly, collide, & randomly spread out.randomly spread out.

Move Move greatergreater concentration concentration toto an area of an area of lesserlesser concentration.concentration.

NO ENERGY USED = PASSIVE NO ENERGY USED = PASSIVE TRANSPORTTRANSPORT

http://highered.mcgrawhttp://highered.mcgraw--hill.com/sites/9834092339/student_view0/chapter38/howhill.com/sites/9834092339/student_view0/chapter38/how_diffusion_works.html_diffusion_works.html

Simple DiffusionSimple Diffusion

The passage of small molecules through the cell The passage of small molecules through the cell membrane.membrane.

No ENERGY USED!!!!!!!!!!No ENERGY USED!!!!!!!!!!

Examples: H20, C02, O2Examples: H20, C02, O2

6

Facilitated DiffusionFacilitated Diffusion

Are Are protein channelsprotein channels that allow diffusion of that allow diffusion of molecules to travel across the cell membrane.molecules to travel across the cell membrane.

NO ENERGY USED!NO ENERGY USED!

Example: GlucoseExample: Glucose

EquilibriumEquilibrium

ConcentrationConcentration of the solute is the of the solute is the SAMESAMEthroughout both sides.throughout both sides.

Molecules of dye Membrane (cross section)

Net diffusion Net diffusion Equilibrium

Molecules of Dye

HIGH TO LOW CONCENTRATION

Keeps passing back & forth

OsmosisOsmosis

TheThe diffusiondiffusion of water through a selectively of water through a selectively

permeable membrane.permeable membrane.

PURE WATER SUGAR WATER

High water concentration Low water concentration

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.htmlhttp://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.html

AnimationsAnimations::OsmosisOsmosis

http://highered.mcgrawhttp://highered.mcgraw--

hill.com/sites/0072495855/student_view0/chapter2/animation__howhill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html_osmosis_works.html

Closure: Passive TransportClosure: Passive TransportDiffusion Osmosis

3 Types of Solutions for 3 Types of Solutions for

OSMOSISOSMOSIS

Isotonic:Isotonic: Concentration of Concentration of solutesolute is is

the same inside & outthe same inside & out

Hypertonic:Hypertonic: Solution has higher Solution has higher

solutesolute concentration that the cellconcentration that the cell

Hypotonic:Hypotonic: Solution has lower Solution has lower solutesolute

concentration than the cell concentration than the cell

7

Animal CellsAnimal Cells

Hypotonic solution Isotonic solution Hypertonic solution

H2OH2O H2O H2O

Lysed Normal Shriveled

Cell BURSTS!

Water into cell

Water same

into & outCell SHRIVELS!

Water out of cell

IsotonicIsotonic HypotonicHypotonic HypertonicHypertonic

3 Types of Solutions 3 Types of Solutions

For Osmosis: Plant CellsFor Osmosis: Plant Cells

Plant cell. Plant cells are turgid (firm) and generally healthiest ina hypotonic environ-

ment, where theuptake of water iseventually balancedby the elastic wallpushing back on thecell.

H2OH2OH2OH2O

Turgid (normal) Flaccid Plasmolyzed

Hypotonic Isotonic Hypertonic

Cell Swells Water same Cell SHRIVELS! (Turgid) into & out Water out of cellWater into cell

http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter38/animation_-_osmosis.html

DO NOW: What substances will not be DO NOW: What substances will not be

able to pass through the cell membrane?able to pass through the cell membrane?

Below is a concept splash. Circle the substances you think will not pass Below is a concept splash. Circle the substances you think will not pass

through.through.

8

3 Types of 3 Types of Active TransportActive Transport

The process where ENERGY is used to The process where ENERGY is used to

move materials across the cell membranemove materials across the cell membrane

against the concentration gradient (low to against the concentration gradient (low to

high)high)

TRANSPORT PROTEINS are used !TRANSPORT PROTEINS are used !

For LARGER moleculesFor LARGER molecules

Active Transport:Active Transport:SodiumSodium--Potassium Pump (Na/K Pump)Potassium Pump (Na/K Pump)

1. 1. Protein PumpsProtein Pumps--

Transport proteins thatTransport proteins that

require energy to dorequire energy to do

workwork

Example: SodiumExample: Sodium--

Potassium pumps arePotassium pumps are

important in nerveimportant in nerve

response. response. Protein changes shapeProtein changes shape--thisthis

requires energy requires energy

Sodium Potassium pumpSodium Potassium pump

http://highered.mcgrawhttp://highered.mcgraw--hill.com/sites/0072437316/student_view0/chapter6/animations.html#hill.com/sites/0072437316/student_view0/chapter6/animations.html#

http://www.coolschool.ca/lor/BI12/unit4/U04L03/active%20transport_jeffedit.swfhttp://www.coolschool.ca/lor/BI12/unit4/U04L03/active%20transport_jeffedit.swf

Active TransportActive Transport

2. 2. EndocytosisEndocytosis

�� The process of taking material into the cell by The process of taking material into the cell by means of pockets by the cell membrane.means of pockets by the cell membrane.

�� A vacuole is formed inside the cytoplasm.A vacuole is formed inside the cytoplasm.

�� Used for LARGER molecules.Used for LARGER molecules.

�� ENERGY is USED !!!!!!!!!!!!!!!!ENERGY is USED !!!!!!!!!!!!!!!!

Active TransportActive Transport

3. 3. ExocytosisExocytosis (out)(out)

�� The process where a vacuole surrounding The process where a vacuole surrounding a material fuses with the cell membrane, a material fuses with the cell membrane,

forcing the contents out of the cell.forcing the contents out of the cell.

��Used for LARGER molecules.Used for LARGER molecules.

��ENERGY is USED!!!!!!!!!!!!ENERGY is USED!!!!!!!!!!!!

Endocytosis & ExocytosisEndocytosis & Exocytosis

9

Analyze: Analyze: Endocytosis or Exocytosis?Endocytosis or Exocytosis?

2 Types of Endocytosis2 Types of Endocytosis

1.1. PhagocytosisPhagocytosis�� Means “cell eating”Means “cell eating”�� The cytoplasm extends & surrounds a particle & The cytoplasm extends & surrounds a particle &

package it within a food molecule.package it within a food molecule.

http://faculty.uca.edu/~johnc/trans1440.htmhttp://faculty.uca.edu/~johnc/trans1440.htmhttp://highered.mcgrawhttp://highered.mcgraw--hill.com/sites/0072437316/student_view0/chapter6/animations.html#hill.com/sites/0072437316/student_view0/chapter6/animations.html#

http://ghs.gresham.k12.or.us/science/ps/sci/soph/diffusion/active.htmhttp://ghs.gresham.k12.or.us/science/ps/sci/soph/diffusion/active.htm

2. Pinocytosis2. Pinocytosis�� Means “Cell Drinking”Means “Cell Drinking”

��The process where tiny pockets are formed filled with liquid The process where tiny pockets are formed filled with liquid along the cell membrane.along the cell membrane.

��Then pinch off to form a vacuole inside the cell.Then pinch off to form a vacuole inside the cell.

http://faculty.uca.edu/~johnc/trans1440.htmhttp://faculty.uca.edu/~johnc/trans1440.htm

http://ghs.gresham.k12.or.us/science/ps/sci/soph/diffusion/active.htmhttp://ghs.gresham.k12.or.us/science/ps/sci/soph/diffusion/active.htm

Closure: Cell TransportClosure: Cell TransportActive

Transport

Passive

Transport

Wrap up:Wrap up:A ReviewA Review

DiffusionDiffusion

Passive TransportPassive Transport

Active TransportActive Transport The EndThe End

10

Active Pump For IonsActive Pump For Ions Facilitated DiffusionFacilitated Diffusion

http://www.chemsoc.org/ExemplarChem/entries/2002/Tim_Smith/transp/

The EndThe End

IonsIons

http://www.chemsoc.org/ExemplarChem/enthttp://www.chemsoc.org/ExemplarChem/ent

ries/2002/Tim_Smith/transp/ries/2002/Tim_Smith/transp/

http://users.rcn.com/jkimball.ma.ultranet/Biolhttp://users.rcn.com/jkimball.ma.ultranet/Biol

ogyPages/D/Diffusion.html#osmosisogyPages/D/Diffusion.html#osmosis

Osmosis & CFOsmosis & CF

http://sun.menloschool.org/~cweavhttp://sun.menloschool.org/~cweaver/cells/c/cell_membrane/er/cells/c/cell_membrane/

11

OsmosisOsmosis

http://www.emc.maricopa.edu/faculty/farabhttp://www.emc.maricopa.edu/faculty/farab

ee/BIOBK/BioBooktransp.htmlee/BIOBK/BioBooktransp.html

OsmosisOsmosis

ExocytosisExocytosis

Diffusion, Phagocytosis, Active Diffusion, Phagocytosis, Active TransportTransport

http://faculty.uca.edu/~johnc/trans1440.hthttp://faculty.uca.edu/~johnc/trans1440.ht

mm

Facilitated Transport: ModelFacilitated Transport: Model

http://www.coolschool.ca/lor/BI12/unit4/U0http://www.coolschool.ca/lor/BI12/unit4/U0

4L03/facilitated%20transport.swf4L03/facilitated%20transport.swf

HonorsHonors

http://www.infections.bayer.com/en/treatmhttp://www.infections.bayer.com/en/treatm

ent/resistance/index.htmlent/resistance/index.htmlhttp://www.coursework.info/Detailed/AS_and_A_Level/Biology/Molecules_Cells/Permeability_of_Cell_Membrane_in_Beetroot_Cells_L4722.html

PlasmolysisPlasmolysis

http://www.microscopyhttp://www.microscopy--

uk.org.uk/mag/indexmag.html?http://www.uk.org.uk/mag/indexmag.html?http://www.microscopymicroscopy--

uk.org.uk/mag/art97/maysnp2.htmluk.org.uk/mag/art97/maysnp2.html

NaK Pump & PhagocytosisNaK Pump & Phagocytosis

http://faculty.uca.edu/~johnc/trans1440.hthttp://faculty.uca.edu/~johnc/trans1440.ht

mm

12

3 Types of Solutions3 Types of Solutions

For Osmosis: Animal CellsFor Osmosis: Animal Cells

Water concentration is the same outside

& inside the cell.

Hypotonic solution Isotonic solution Hypertonic solution

H2OH2O H2O H2O

Lysed Normal Shriveled

Hypotonic=

Outside -Low solute

concentration (greater water molecules)

High to low inside cell.

SWELLS

Hypertonic=

Outside- High solute

concentration (less water molecules)

High to low outside

cell

SourcesSources

http://iweb.tntech.edu/mcaprio/lab_5.htmhttp://iweb.tntech.edu/mcaprio/lab_5.htm

http://www.etomica.org/app/modules/sites/Osmosis/Background1.htmlhttp://www.etomica.org/app/modules/sites/Osmosis/Background1.html