Daily Warm up 9/17/101. What two things must happen for diffusion

to occur?

2. Define these three words: Isotonic solution, Hypotonic, Hypertonic. (where is there more water in each scenario)

3. If your cells were to be placed in salt water what do you think would happen and why?

True and False

1. Only 25% of the world is left handed? 2. Each square inch of human skin

consists of twenty feet of blood vessels.

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Movement through Movement through Cell MembranesCell Membranes-

Gateway to the CellGateway to the Cell

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Cell Membrane controls Cell Membrane controls HomeostasisHomeostasis

•Balanced internal condition of cells

•Also called equilibrium•Maintained by plasma

membrane controlling what enters & leaves the cell

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Structure of the Structure of the Cell MembraneCell Membrane

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PhospholipidsPhospholipids

CholesterolCholesterol

Proteins(peripheral and integral)Carbohydrates (glucose)

Membrane ComponentsMembrane Components

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LABEL THE STRUCTURES

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PhospholipidsPhospholipidsMake up the cell

membrane

Contains 2 fatty acid chains called the tailsContains one glycerol called the head.

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Heads are hydrophilichydrophilic “water loving”Tails are hydrophobichydrophobic “water fearing”

Cell MembraneCell Membrane

Makes membrane “Selective” in what crosses

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Cell MembraneCell MembraneHydrophobic molecules pass easily; hydrophilic DO NOT

The cell membrane is made of 2 layers of phospholipidphospholipids called the lipid bilayerbilayer

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Small molecules and larger hydrophobic molecules move through easily.e.g. O2, CO2, H2O

Semipermeable Semipermeable MembraneMembrane

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Ions, hydrophilic molecules larger than water, and large molecules such as proteins do not move through the membrane on their own.

Semipermeable Semipermeable MembraneMembrane

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Types of Transport Types of Transport Across Cell Across Cell MembranesMembranes

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Simple DiffusionSimple Diffusion

•Requires NONO energy

•Molecules move from area of HIGH HIGH to LOWto LOW concentrationWhere in this picture will the purple molecules move?

Diffusion• Two things

need to happen in a cell in order for diffusion to occur… what are they?

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1. Cell membrane must be permeable to that substance.

2. There must be a concentration gradient (needs to be higher in one area and move to lower area)

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DIFFUSIONDIFFUSION

Diffusion is a PASSIVEPASSIVE process which means no energy is used to make the molecules move, they have a natural KINETIC ENERGY

STOP POINT: • Diffusion of Food Coloring Demonstration.1.EVERYONE Take out a piece of paper (# 1-3). 2.Have someone at your table put in 4 drops of the

food coloring I bring around. 3.Answer these questions- without talking:

1. What happened when the food coloring was added?

2. What did the water look like before the color was added, while it was being added and once it was finished?

3. How did the water end up turning red? (tell me what the molecules were doing).

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Sugar Cube Diffusion• Answer the three questions as you watch

the sugar cube in the next cup of water. 1. What happened when the sugar cube

was added? 2. What did the water look like before

the sugar was added, while it was being added and once it was finished?

3. Explain to me the process of diffusion and how this was an example?

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Diffusion of LiquidsDiffusion of Liquids

Sugar Cube Diffusion

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Diffusion through a Diffusion through a MembraneMembrane

Cell membrane

Solute moves DOWN concentration gradient (HIGH to LOW)

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OsmosisOsmosis• Diffusion of water across a Diffusion of water across a

membranemembrane

• Moves from HIGH water potential Moves from HIGH water potential (low solute) to LOW water potential (low solute) to LOW water potential (high solute)(high solute)

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Diffusion of HDiffusion of H22O Across O Across A Membrane (Osmosis)A Membrane (Osmosis)

High H2O potentialLow solute concentration

Low H2O potentialHigh solute concentration

3 Types of Osmosis:

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1.Isotonic Solutions: the solute and water concentration is the same inside the cell as it is outside the cell

2.Hypertonic Solutions: Higher concentration outside the cell than inside the cell.

3.Hypotonic Solutions: Higher concentration inside the cell than outside the cell.

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Cell in Isotonic SolutionCell in Isotonic Solution

CELLCELL

10% NaCL90% H2O

10% NaCL

90% H2O

What is the direction of water movement?The cell is at _______________.equilibrium

ENVIRONMENTENVIRONMENT

NO NET NO NET MOVEMENMOVEMENTT

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Cell in Hypotonic Cell in Hypotonic SolutionSolution

CELLCELL

10% NaCL90% H2O

20% NaCL

80% H2O

What is the direction of water movement?Water moves into the cell

H2O

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Cell in Hypertonic Cell in Hypertonic SolutionSolution

CELLCELL

15% NaCL85% H2O

5% NaCL95% H2O

What is the direction of water movement?

ENVIRONMENTENVIRONMENT

Water moves out of the cell.

H2O

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Cells in SolutionsCells in Solutions

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Isotonic Solution

NO NET MOVEMENT OF

H2O (equal amounts entering

& leaving)

Hypotonic Solution

Water enters cell- can cause it to burst

Hypertonic Solution

Water leaves cell until it “deflates”

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What will happen?What will happen?

How does this relate to Anatomy?

• Discuss at your table this question and appoint someone to share your answer:

• What would happen to your blood cells if the fluid surrounding them had too much salt?

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Osmosis in Red Blood Osmosis in Red Blood CellsCells

IsotonicIsotonic Hypotonic

Hypertonic

What Happens to Blood Cells?

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hypotonic hypertonic isotonic

hypertonic isotonic hypotonic

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STOP POINT:

OSMOSIS ACTIVITY LAB

At your lab tables you are working in groups of 2 or 3. Each lab table should be divided into 2 groups.

WAIT FOR MY DIRECTIONS!

Send one person from your group to the materials table to receive your materials.

WAIT for FURTHER DIRECTIONS.

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Types of Transport:

1. Passive Transport• Includes: Diffusion,

Osmosis, and Facilitated Diffusion

2. Active Transport

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Three Forms of Transport Across the MembraneThree Forms of Transport Across the Membrane

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Passive Passive TransportTransport

Simple DiffusionSimple Diffusion

Doesn’tDoesn’t require require energyenergy

Moves Moves high to lowhigh to low concentrationconcentration Example: Example: OxygenOxygen or or waterwater diffusing into a diffusing into a cell and cell and carbon carbon dioxidedioxide diffusing out diffusing out.

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Passive Passive TransportTransport

Facilitated diffusion

Doesn’t require energy

Uses transport proteins to move high to low concentrationExamples: Examples: GlucoseGlucose or or amino acidsamino acids moving moving from blood into a from blood into a cell.cell.

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Proteins Are Critical to Proteins Are Critical to Membrane FunctionMembrane Function

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Types of Transport Types of Transport ProteinsProteins

• 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 DiffusionFacilitated Diffusion

Molecules will move through Molecules will move through the the porespores in in Channel ProteinsChannel Proteins..

copyright cmassengale

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Facilitated DiffusionFacilitated Diffusion

• SomeSome Carrier Carrier proteinsproteins do not do not extend through the extend through the membrane.membrane.

• They They bond and bond and drag moleculesdrag molecules through the lipid through the lipid bilayer and release bilayer and release them on the them on the opposite side.opposite side.

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Carrier ProteinsCarrier Proteins• Other carrier Other carrier

proteins proteins change shapechange shape to move to move materials materials across the cell across the cell membranemembrane

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Active TransportActive Transport

Requires energy or ATP

Moves materials from LOW to HIGH concentration

AGAINST concentration gradient

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Active transportActive 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 Sodium-Potassium PumpPump

3 Na+ pumped in for every 2 K+ pumped out; creates a membrane

potential

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Moving the “Big Stuff”Moving the “Big Stuff”

Molecules are Molecules are moved outmoved out of the cell by of the cell by vesiclesvesicles that that fusefuse with the plasma membrane. with the plasma membrane.

ExocytosExocytosisis-

moving things out.

This is how many This is how many hormoneshormones are secreted and how are secreted and how nerve cellsnerve cells communicate with one another communicate with one another.

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ExocytosisExocytosisExocytic Exocytic vesicle vesicle immediately immediately after fusion after fusion with plasma with plasma membrane.membrane.

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Moving the “Big Moving the “Big Stuff”Stuff”Large molecules move materials into the Large molecules move materials into the

cell by one of cell by one of three forms of endocytosisthree forms of endocytosis.

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PinocytosisPinocytosis

Most Most commoncommon form of endocytosis form of endocytosis. Takes in Takes in dissolveddissolved molecules as a molecules as a vesiclevesicle.

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PinocytosisPinocytosis

• Cell forms an Cell forms an invaginationinvagination

• Materials Materials dissolve in dissolve in waterwater to be to be brought into brought into cellcell

• Called Called “Cell “Cell Drinking”Drinking”

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Endocytosis – Phagocytosis Endocytosis – Phagocytosis

Used to Used to engulf large particlesengulf large particles such such as food, as food, bacteriabacteria, etc. into vesicles, etc. into vesicles

Called Called “Cell Eating”“Cell Eating”

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Phagocytosis About to OccurPhagocytosis About to Occur

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PhagocytoPhagocytosissis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue)

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ExocytosisExocytosis The opposite of endocytosis is exocytosis. The opposite of endocytosis is exocytosis. Large moleculesLarge molecules that are manufactured in that are manufactured in

the cell are the cell are releasedreleased through the cell through the cell membranemembrane..

Inside Cell Cell environment

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How does osmosis or Diffusion play a role in the human body?

What is the main difference between Passive transport and Active transport?

What is endocytosis and exocytosis?

What happens if a red blood cell is in a hypertonic solution? Hypotonic? Isotonic?

REVIEW QUESTIONS

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STOP POINT

Membrane Transport Worksheet Packet