Plasma Membrane

Plasma MembranePlasma Membrane

Movement in and out of a cellMovement in and out of a cell


A flexible boundary between the cell and A flexible boundary between the cell and it’s environmentit’s environment

JOB: allow steady supply of nutrients to JOB: allow steady supply of nutrients to come into the cell no matter what the come into the cell no matter what the external conditions areexternal conditions are Too much of any nutrient or other substance Too much of any nutrient or other substance

can be harmfulcan be harmful

Plasma Membrane (PM)Plasma Membrane (PM)

Process of maintaining balance in a cell’s Process of maintaining balance in a cell’s environment is environment is homeostasishomeostasis Selective permeability Selective permeability allows some allows some

molecules to pass through while keeping molecules to pass through while keeping other outother out

Ex: screen on a windowEx: screen on a window

PM: StructurePM: StructureLipidsLipids are large are large biomolecules biomolecules composed of glycerol composed of glycerol and 3 fatty acidsand 3 fatty acids If a phosphate If a phosphate

replaces one of the replaces one of the fatty acids, a fatty acids, a phospholipidphospholipid is is formedformed

PM is made up of a PM is made up of a phospholipid bilayerphospholipid bilayer (2 layers of (2 layers of phospholipids back-to-phospholipids back-to-backback

PM: StructurePM: Structure

2 2 fatty acidfatty acid chains are chains are non-polarnon-polar and and form the form the tailtail of the phospholipid of the phospholipid

The The headhead contains the contains the phosphatephosphate group group and is and is polarpolar

ContinuedContinued

Water is a key component of lifeWater is a key component of life

Polar head allows PM to interact with Polar head allows PM to interact with watery environment (H2O is a polar watery environment (H2O is a polar molecule) (molecule) (Hydrophyllic) Hydrophyllic) water lovingwater loving

Non-polar tails avoid water (Non-polar tails avoid water (HydrophobicHydrophobic) ) water fearingwater fearing

Phospholipid molecules make a sandwich Phospholipid molecules make a sandwich with tails in, heads out.with tails in, heads out.

PM: Fluid Mosaic ModelPM: Fluid Mosaic ModelPM is not static (it PM is not static (it doesn’t stay still)doesn’t stay still)Phospholipids move Phospholipids move within the membrane within the membrane like water molecules like water molecules move with currents in a move with currents in a lakelakeProteins also move Proteins also move through phospholipids through phospholipids like boatslike boats Proteins create “mosaic” Proteins create “mosaic”

or pattern on membrane or pattern on membrane surfacesurface

PM: Other ComponentsPM: Other Components

CholesterolCholesterol: helps stabilize phospholipids : helps stabilize phospholipids by preventing tails from sticking togetherby preventing tails from sticking together

Transport proteins:Transport proteins: Span entire Span entire membranemembrane Regulate which molecules enter and leave Regulate which molecules enter and leave

cellcellProteins on OUTER surface help cells identify Proteins on OUTER surface help cells identify chemical signals and each otherchemical signals and each other

Proteins on INNER surface help attach PM to cells Proteins on INNER surface help attach PM to cells internal support structure internal support structure flexibility flexibility

PM: Other ComponentsPM: Other Components

Show me What You KnowShow me What You Know

The structure most responsible for The structure most responsible for maintaining cell homeostasis is the ___.maintaining cell homeostasis is the ___.

A.A. CytoplasmCytoplasm

B.B. MitochondrionMitochondrion

C.C. Cell WallCell Wall

D.D. Plasma MembranePlasma Membrane

Show Me What You KnowShow Me What You Know

Movement of particles from an area of Movement of particles from an area of higher concentration to one of lower higher concentration to one of lower concentration is ______________?concentration is ______________?


Movement of particles from an area of Movement of particles from an area of higher concentration to one of lower higher concentration to one of lower concentration is ______________?concentration is ______________?

DiffusionDiffusion


Which of the following structures is the most Which of the following structures is the most complex?complex?

A.A. CellCell

B.B. Organ SystemOrgan System

C.C. OrganOrgan

D.D. TissueTissue

ActivityActivity

Write your summary of notesWrite your summary of notes

On the left hand side of your notebook, On the left hand side of your notebook, draw and label a phospholipid bilayer. draw and label a phospholipid bilayer. Use p. 177-178 of your text. Don’t forget Use p. 177-178 of your text. Don’t forget to add color.to add color.


Day TwoDay Two

Cell TransportCell Transport

2 types of cell transport:2 types of cell transport: Passive TransportPassive Transport: Movement of particles : Movement of particles

across a membrane requiring across a membrane requiring NONO energy energyHigh concentration High concentration Low concentration Low concentration

Active Transport:Active Transport:

Passive Transport: OsmosisPassive Transport: OsmosisOsmosis:Osmosis: diffusion of H2O across a diffusion of H2O across a selectively permeable membrane.selectively permeable membrane. Ex. If membrane that only allows water to Ex. If membrane that only allows water to

pass through, water will diffuse to side where pass through, water will diffuse to side where H2O concentration is lower and will continue H2O concentration is lower and will continue until equal concentration is reached on both until equal concentration is reached on both sidessides

Passive Transport: OsmosisPassive Transport: Osmosis

Isotonic SolutionIsotonic Solution: Concentration is the : Concentration is the samesame both both insideinside andand outsideoutside the cell the cell

Hypotonic Solution:Hypotonic Solution: concentration is concentration is lower lower outsideoutside than inside the cell than inside the cell

Hypertonic Solution: Hypertonic Solution: concentration is concentration is higherhigher outside outside than inside the cellthan inside the cell

Passive Transport: OsmosisPassive Transport: Osmosis

Passive Transport: DiffusionPassive Transport: Diffusion

Diffusion:Diffusion: net movement of particles from net movement of particles from higher concentration to lower.higher concentration to lower. Results from random movement of particles Results from random movement of particles

running into one anotherrunning into one another Very slow process because it relies on Very slow process because it relies on

random motionrandom motion

ContinuedContinued

3 key factors:3 key factors:Concentration: Increase in concentration will Concentration: Increase in concentration will increase the rate of diffusionincrease the rate of diffusion

Temperature: Increase in temperature will increase Temperature: Increase in temperature will increase rate of diffusionrate of diffusion

Pressure: Increase in pressure will increase rate of Pressure: Increase in pressure will increase rate of diffusiondiffusion

Dynamic EquilibriumDynamic Equilibrium: continuous : continuous movement with no overall concentration movement with no overall concentration changechange

Passive Transport: DiffusionPassive Transport: Diffusion

Active TransportActive Transport

Active Transport:Active Transport: Movement of materials Movement of materials through a membrane against a through a membrane against a concentration gradient (concentration gradient (requires energyrequires energy))

Active Transport: Carrier Transport Active Transport: Carrier Transport ProteinsProteins

Carrier Proteins:Carrier Proteins: Bind with particle of the Bind with particle of the

substance to be substance to be transportedtransported

Lock and Key!!Lock and Key!! With the right fit, chemical With the right fit, chemical

energy allows shape of energy allows shape of carrier protein to change carrier protein to change releasing particle on other releasing particle on other sideside

Much like the action of a Much like the action of a doordoor

Active Transport: Carrier Active Transport: Carrier ProteinsProteins

Active Transport: EndocytosisActive Transport: Endocytosis

EndocytosisEndocytosis occurs when the cell occurs when the cell surrounds and takes in large material from surrounds and takes in large material from it’s environmentit’s environment

Does not pass through membraneDoes not pass through membrane

Engulfed and enclosed by part of the PMEngulfed and enclosed by part of the PM

Membrane breaks away creating a vacuole with Membrane breaks away creating a vacuole with the material insidethe material inside

Phagocytosis: Phagocytosis: cell brings in a solidcell brings in a solid Pinocytosis:Pinocytosis: cell brings in liquid cell brings in liquid

Active Transport: ExocytosisActive Transport: Exocytosis

Exocytosis occurs when the cell expels or Exocytosis occurs when the cell expels or secretes large particles from the cellsecretes large particles from the cell Ex. wastes, hormonesEx. wastes, hormones


Water moves into a cell placed in a(n) Water moves into a cell placed in a(n) __________ solution.__________ solution.

A.A. OsmoticOsmotic

B.B. HypertonicHypertonic

C.C. HypotonicHypotonic

D.D. IsotonicIsotonic


Water moves out of a cell if the cell is placed Water moves out of a cell if the cell is placed in a(n) ___________ solution.in a(n) ___________ solution.

A.A. HypertonicHypertonic

B.B. IsotonicIsotonic

C.C. HyptonicHyptonic

D.D. passivepassive


A cell moves particles from a region of A cell moves particles from a region of lesser concentration to a region of lesser concentration to a region of greater concentration by ____________.greater concentration by ____________.

A.A. Facilitated diffusionFacilitated diffusion

B.B. Passive transportPassive transport

C.C. OsmosisOsmosis

D.D. Active TransportActive Transport

ActivityActivity

Write a summary for your notesWrite a summary for your notes

Create a foldable to be glued into the Create a foldable to be glued into the activity page of your notebook. Use p. 195 activity page of your notebook. Use p. 195 of your text to create the foldable. Don’t of your text to create the foldable. Don’t forget to use at least 4 colorsforget to use at least 4 colors

Plasma Membrane

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