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Golgi BodiesGolgi Bodies Stacks of Stacks of flattened sacsflattened sacs Have a shipping side (Have a shipping side (cis cis

faceface) & a receiving side ) & a receiving side ((trans facetrans face))

Receive Receive proteinsproteins made by made by ERER

Transport vesiclesTransport vesicles with with modified proteins pinch off modified proteins pinch off the endsthe ends

Transport vesicle

CIS

TRANS

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Golgi BodiesGolgi Bodies

Look like a stack of pancakes

Modify, sort, & packagemolecules from ERfor storage OR transport out of cell

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Golgi AnimationGolgi Animation

Materials are transported from Rough ER to Golgi to the cell membrane by

VESICLES

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The Plasma MembraneThe Plasma Membrane -

Gateway to the CellGateway to the Cellcopyright cmassengale

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Photograph of a Cell MembranePhotograph of a Cell Membrane

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Cell MembraneCell MembraneThe cell

membrane is flexibleflexible and allows a unicellular organism to move

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HomeostasisHomeostasis 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 MembraneFunctions of Plasma Membrane

Protective barrierProtective barrier

Regulate transport in & out of Regulate transport in & out of cell cell (selectively permeable)(selectively permeable)

Allow cell recognitionAllow cell recognition

Provide anchoring sites for Provide anchoring sites for filaments filaments of cytoskeletonof cytoskeleton

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Functions of Plasma MembraneFunctions of Plasma Membrane

Provide a binding site for Provide a binding site for enzymesenzymes

Interlocking surfaces bind cells Interlocking surfaces bind cells together (junctions)together (junctions)

Contains the cytoplasm (fluid in Contains the cytoplasm (fluid in cell) cell)

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Movement across the Cell Membrane

Types of Transport

1.Simple Diffusion2.Osmosis 3. Facilitated Diffusion4. Active Transport

Diffusion Move from HIGH to LOW concentration

“passive transport” no energy needed Move across membrane

diffusion osmosis

movement of water

Diffusion across cell membrane

INfoodcarbohydratessugars, proteinsamino acidslipidssalts, O2, H2O

OUTwasteammoniasaltsCO2

H2O products

cell needs materials in & products or waste out

IN

OUT

Can it be an impenetrable boundary? NO!

Diffusion through phospholipid bilayer

What molecules can get through directly? fats & other lipids

inside cell

outside cell

lipid

salt

aa H2Osugar

NH3

What molecules can NOT get through directly?

polar molecules H2O

ions salts, ammonia

large molecules starches, proteins

Osmosis is diffusion of water Water is very important to life,

so we talk about water separately Diffusion of water from

high concentration of water to low concentration of water across a

semi-permeable membrane

Channels through cell membrane Membrane becomes semi-permeable

with protein channels specific channels allow specific material

across cell membrane

inside cell

outside cell

sugaraaH2O

saltNH3

Facilitated Diffusion Diffusion through protein channels

Move high to low. Proteins move specific molecules across

cell membrane no energy needed

“The Bouncer”“The Bouncer”

open channel = fast transport

facilitated = with help

high

low

Active Transport

“The Doorman”“The Doorman”

conformational change

Cells may need to move molecules against concentration gradient (low to high) protein “pump” “costs” energy

ENERGY

low

high

Getting through cell membrane Passive Transport

Simple diffusion Movement molecules through cell membrane high low concentration gradient

Osmosis Movement water through protein high low concentration gradient

Facilitated transport through a protein channel high low concentration gradient

Active transport diffusion against concentration gradient

low high uses a protein pump requires ATP

ENERGY

Transport summary

simplediffusion

facilitateddiffusion

activetransport

ENERGY

Any Questions??