MEMBRANE TRANSPORT �REVIEW

Cell Membrane

High to Low

With the flow (gradient)

Passive Transport

(no energy needed)

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Diffusion

Osmosis (water)

Facilitated diffusion (w/ protein)

Low to High

Against the tide (gradient)

Active Transport

(energy needed)

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Active Molecular Transport (ATP and integral protein)

Endocytosis = in (phago-eating, pino-drinking)

Exocytosis = out

-Protein = transport

-Cholesterol = stability

-Phospholipids = semipermeable bilayer

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**Cells must stay

SMALL to have a

Good SA/V ratio**

Osmosis:

watER moves to hypERtonic area (where

highER concentration of solute is present)

Question

Answer

Teacher Quizizz Link

Student Quizizz Link

SOL Questions

Integral

Peripheral

Peripheral

Glycoprotein

Hydrophilic, Polar Heads

Hydrophobic, Nonpolar Tails

Cholesterol

Cell Membrane: A Phospholipid Bilayer with Proteins (transport) and Cholesterol (support/stability)

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*Selectively/Semi

Permeable*

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Membrane Transport

• Passive
• HIGH to LOW
• WITH the concentration gradient
• NO ENERGY

• Active
• LOW to HIGH
• AGAINST concentration gradient
• YES ENERGY

What is diffusion?

• Movement of SMALL molecules through the phospholipid bilayer. EX: oxygen & carbon dioxide
• Molecules spread out, just like the food coloring molecules spread out in our experiment

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• Movement from HIGH concentration to LOW concentration
• WITH the concentration gradient
• NO ENERGY needed

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• The simplest form of PASSIVE transport

What is Equilibrium?

• Concentration inside the cell is equal to outside of the cell
• Movement in and out

Equilibrium

What is Osmosis?

• Osmosis is the diffusion of WATER!
• It is passive transport
• Remember tonicity for beaker questions:
• Always look at the SOLUTE concentration (not water concentration)
• hypER is highER concentration
• hypO is lOw concentration
• iso means same or equal concentration
• watER moves to hypER

Osmosis Beakers

Solute 15%

Water 85%

Solute 40%

Water 60%

Solute 3%

Water 97%

Solute 30%

Water 70%

Solute 20%

Water 80%

Solute 3%

Water 97%

Cell is HYPER

Solution is HYPO

Water moves INTO cell

Cell will swell

Cell is HYPO

Solution is HYPER

Water moves OUT OF cell

Cell will shrink

Cell is ISO

Solution is ISO

Water moves IN & OUT of cell

Cell will remain the same

Egg Osmosis Lab

Egg in Syrup

• Syrup (solution) is higher concentration = HYPERtonic
• Egg (cell) is lower concentration = HYPOtonic
• Water moves to syrup (solution)
• Egg (cell) shrinks because water is moving OUT OF the cell
• Volume of solution increases

Egg in Pure Water

• Water (solution) is lower concentration = HYPOtonic
• Egg (cell) is higher concentration = HYPERtonic
• Water moves to egg (cell)
• Egg (cell) swells because water is moving INTO the cell
• Volume of solution decreases

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What did we measure in the lab?

Mass of the egg

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What tool did we use to measure it?

electronic balance

What is Facilitated Diffusion?

• A form of PASSIVE transport
• Movement from HIGH concentration to LOW concentration
• WITH the concentration gradient
• NO ENERGY needed

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• Uses an INTEGRAL PROTEIN to help move molecules

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What is active molecular transport?

• A form of ACTIVE transport
• Movement of molecules from LOW concentration to HIGH concentration
• AGAINST the concentration gradient
• YES, ENERGY needed

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• Proteins are used in active molecular transport, and they need energy in the form of ATP!

What is Endocytosis?��When a cell brings material IN using infoldings of the cell membrane to make a vesicle

PINOcytosis

• Cell drinking
• Bringing in liquid

PHAGOcytosis

• Cell eating
• Bringing in large particles, like bacteria

What is EXocytosis?

• When the contents of a vacuole EXit the cell as the vacuole fuses with the cell membrane

Quizlet

https://quizlet.com/_91897v?x=1jqt&i=1j7usc