Plasma MembranePlasma Membrane

Plasma MembranePlasma Membrane

StructureStructure

Phospholipid bi-layerPhospholipid bi-layer

StructureStructure

Phosphate Head – Hydrophilic Phosphate Head – Hydrophilic

Lipid Tail – Hydrophobic Lipid Tail – Hydrophobic

Glycoprotein/Glycolipids – Cell markersGlycoprotein/Glycolipids – Cell markers

Carrier Protein – Passive and ActiveCarrier Protein – Passive and Active

Function of the Plasma Function of the Plasma MembraneMembrane

- - selectively permeableselectively permeable membrane membrane - allows for communication between cells- allows for communication between cells - provides the cell with a specific “marker”- provides the cell with a specific “marker”

Carrier ProteinCarrier Protein

Passive Channel – Leakage channelPassive Channel – Leakage channel

Active Channel – Open and close to let Active Channel – Open and close to let larger molecules throughlarger molecules through

- Uses Cellular energy - Uses Cellular energy (ATP)(ATP)

Channel Protein

Plasma MembranePlasma Membrane

Construction of the Cell Membrane - Learning Ac - Flash Player Installation

Particle TheoryParticle Theory

1. All matter is made of particles1. All matter is made of particles

2. The particles are in constant motion 2. The particles are in constant motion (Kinetic motion of particles) (Kinetic motion of particles)

3. The closer the particles are together, 3. The closer the particles are together, the greater the attractiveness between the greater the attractiveness between them.them.

Particle TheoryParticle Theory

Solids – definite shape and volumeSolids – definite shape and volume

Liquids – definite volume but indefinite Liquids – definite volume but indefinite shapeshape

Gases – indefinite shape and volumeGases – indefinite shape and volume Matter

Cellular TransportCellular Transport

Passive Transport – use no cellular Passive Transport – use no cellular energyenergy

A) DiffusionA) Diffusion B) OsmosisB) Osmosis C) Facilitated DiffusionC) Facilitated Diffusion

A. DiffusionA. Diffusion - Movement of particles from an area of - Movement of particles from an area of

High concentration to an area of Low High concentration to an area of Low concentrationconcentration

- Particles will move until they are evenly - Particles will move until they are evenly distributed in an distributed in an EquilibriumEquilibrium

- Particles continue - Particles continue random movementrandom movement, , but it has no affect on the equilibriumbut it has no affect on the equilibrium

Diffusion

B. OsmosisB. Osmosis

- special - special diffusiondiffusion where where waterwater passes passes through a through a selectively permeable selectively permeable membrane membrane from an area of High from an area of High concentration to an area of Low concentration to an area of Low concentrationconcentration

Osmosis Osmosis II

C. Facilitated DiffusionC. Facilitated Diffusion

- special - special diffusion diffusion that is made faster by that is made faster by using Passive Channels (leakage using Passive Channels (leakage channels)channels)

- can result in a - can result in a conformational conformational change in change in the shape of the protein.the shape of the protein.

Facilitative Diffusion Facilitated Diffusion II Facilitated Diffusion III

Environments that Cells Environments that Cells might find themselves in: might find themselves in:

A) Hypotonic Solutions – greater concentration A) Hypotonic Solutions – greater concentration of water of water OUTSIDEOUTSIDE the cell the cell

B) Hypertonic Solutions – greater B) Hypertonic Solutions – greater concentration of water concentration of water INSIDEINSIDE the cell the cell

C) Isotonic Solutions – even concentrations of C) Isotonic Solutions – even concentrations of water inside and outside the cellwater inside and outside the cell

How will cells react in How will cells react in each??each??

Animal cellsAnimal cells

Hypotonic SolutionHypotonic Solution - water moves into the cell (osmosis), the - water moves into the cell (osmosis), the

cell swells, and may burst (cell swells, and may burst (CytolysisCytolysis))

Hypotonic Solution

How will cells react in How will cells react in each?each?

Animal cellsAnimal cells

Hypertonic – water moves from inside Hypertonic – water moves from inside out and the cell shrivels and dehydratesout and the cell shrivels and dehydrates

Hypertonic

How will cells react in How will cells react in each?each?

Animal cellsAnimal cells

Isotonic – water moves in and out of the Isotonic – water moves in and out of the cell at the same rate cell at the same rate (Random movement)(Random movement)

Isotonic

Try these:Try these:

1. The plasma membrane consists of ___ layers.1. The plasma membrane consists of ___ layers. 2. The molecules that make up the plasma membrane are 2. The molecules that make up the plasma membrane are

called ______called ______ 3. The phosphate heads like water and are called ______.3. The phosphate heads like water and are called ______. 4. The lipid tails don’t like water and are called ______.4. The lipid tails don’t like water and are called ______. 5. Special protein molecules called _____ are found 5. Special protein molecules called _____ are found

throughout the plasma membrane.throughout the plasma membrane. 6. Cell markers called _______ are attached to the top of 6. Cell markers called _______ are attached to the top of

these protein molecules.these protein molecules. 7. The Particle Theory states that all matter is made up of 7. The Particle Theory states that all matter is made up of

tiny particles and that they are in _________.tiny particles and that they are in _________. 8. Cells need to move materials in and out to maintain a 8. Cells need to move materials in and out to maintain a

state of balance between what is inside and outside. This state of balance between what is inside and outside. This balance is called _______ balance is called _______

9. Cells move materials in and out in 2 ways. ___________ 9. Cells move materials in and out in 2 ways. ___________ and ___________and ___________

10. ________transport doesn’t require the cell to expend 10. ________transport doesn’t require the cell to expend any energy.any energy.

11. ________ transport requires the cell to use some of it’s 11. ________ transport requires the cell to use some of it’s own energy stored in _____own energy stored in _____

12. There are 3 types of Passive Transport ________, 12. There are 3 types of Passive Transport ________, _________ and __________._________ and __________.

13. Movement of any particles from H to L is called 13. Movement of any particles from H to L is called ________.________.

14. Movement of water molecules from H to L is called 14. Movement of water molecules from H to L is called ________.________.

15. Diffusion of particles that are helped by carrier protein is 15. Diffusion of particles that are helped by carrier protein is called __________.called __________.

Review of Passive Review of Passive TransportTransport

Passive Transport

Another look:Another look:

Solutions

What about plant cells?What about plant cells?

Hypotonic – water moves in and Turgor Hypotonic – water moves in and Turgor Pressure in the cell increases.Pressure in the cell increases.

What about plant cells?What about plant cells?

Hypertonic – water moves out of the cell Hypertonic – water moves out of the cell and turgor pressure drops and turgor pressure drops

- the plasma membrane pulls - the plasma membrane pulls away from the cell wall and the cell wilts.away from the cell wall and the cell wilts.

Plasmolysis Plasmolysis

What about plant cells?What about plant cells?

Isotonic – water moves in and out at the Isotonic – water moves in and out at the same rate.same rate.

Another look:Another look:

Cellular TrafficCellular Traffic

Active Transport (uses ATP)Active Transport (uses ATP) A) EndocytosisA) Endocytosis B) ExocytosisB) Exocytosis C) Movement against the “concentration C) Movement against the “concentration

gradient”.gradient”.

Cellular TrafficCellular Traffic

A) Endocytosis – movement of large particles A) Endocytosis – movement of large particles into a cell packaged in vesicles . The cell uses into a cell packaged in vesicles . The cell uses energy stored in ATP energy stored in ATP

i) Phagocytosis - i) Phagocytosis -

- cell engulfs a large food particle by wrapping - cell engulfs a large food particle by wrapping it’s cytoplasmic arms around the particle it’s cytoplasmic arms around the particle

Phagocytosis

Cellular TrafficCellular Traffic

i) Pinocytosis – cell engulfs a smaller i) Pinocytosis – cell engulfs a smaller particle or water droplet into the cell by particle or water droplet into the cell by indenting the plasma membrane. The cell indenting the plasma membrane. The cell uses energy stored in ATPuses energy stored in ATP

Pinocytosis Pinocytosis 2

Cellular TrafficCellular Traffic

B) Exocytosis – excreting materials from B) Exocytosis – excreting materials from a cell packaged in vesicles. The cell uses a cell packaged in vesicles. The cell uses energy stored in ATP.energy stored in ATP.

ExocytosisExocytosis Exocytosis 2Exocytosis 2

Cellular TrafficCellular Traffic

C) Movement against the Concentration C) Movement against the Concentration Gradient (L to H)Gradient (L to H)

Particles are drawn against the concentration Particles are drawn against the concentration gradient using active channels that open and gradient using active channels that open and close using cellular energyclose using cellular energy

L to H L to H L-H L-H

Cellular Transport ReviewCellular Transport Review

Thirst ReflexThirst Reflex

Passive TransportPassive Transport

EnvironmentsEnvironments

Drag and Drop Cell membraneDrag and Drop Cell membrane

HomeostasisHomeostasis

All these examples of cellular traffic are All these examples of cellular traffic are designed to help the cell maintain a state designed to help the cell maintain a state of balance between the inside and the of balance between the inside and the outside of the cell.outside of the cell.