Passive vs Active Transport

​Today we are learning the difference between...

​

Passive Transport vs

Active Transport

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An example of Passive Transport is

Diffusion

Movement of molecules from high concentration to low concentration.

Stops when equilibrium is reached

You see it ALL THE TIME.

​

​Maybe perfume molecules move around the subway car or the smell of breakfast moves around you home.

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IT DOES NOT REQUIRE ENERGY

Multiple Choice

How do molecules move during diffusion?

• From high concentration to low concentration

• From low concentration to high concentration

Equilibrium

Molecules are equally spread out.

​This is the goal of diffusion. It wants the same concentration inside and outside the cell...

...speaking of cells

Molecules diffuse in and out cells all the time.

​

​Oxygen needs to diffuse INTO your cells so you stay alive

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​and Carbon Dioxide needs to diffuse out of the cells so you can breath it out. PHEW!

Remember:

Diffusion is how molecules cross your cell membrane WITHOUT any energy

​

​IT'S FREE and doesn't cost you any energy.

Multiple Choice

Does passive transport require energy?

• Yes

• No

Multiple Choice

Osmosis is the movement of _____ across a membrane.

• food
• energy
• oxygen
• water

Multiple Choice

During osmosis

• water moves from high to low concentration
• large or oddly shaped molecules move across a cell membrane
• water moves when energy is used

Water can move in and out of cells DEPENDING where the concentration is lower. For example if a cell has a higher water concentration than the outside then...

​Those cells looked like they shrank because water left the cells toward the lower concentrated outside

The opposite can happen too. For example if a cell has a lower water concentration than the outside then...

Open Ended

Why shouldn't you drink salt water?

​Your cells in a hypotonic solution. Water rushes into the cells!

Multiple Choice

A person would never have pure water put into their veins in a hospital because their cells would...

• Shrink/Dehydrate
• Expand

Which egg do you think just came out of salty solution?

Multiple Choice

Which egg was put in salt water?

• The one on the left

• The egg in the middle

• The egg on the right

What if a cell needs nutrients from a lower concentration area...

​

​

​Let's explore ACTIVE TRANSPORT!

⚡Active Transport⚡

Cell transport that REQUIRES ENERGY

Active Transport

• Movement of substances from areas of low concentration to areas of high concentrations

• Requires: ENERGY from the cell (ATP), and a transport proteins (these are often called pumps)

ACTIVE TRANSPORT

• Transport of ions: Protein pumps move ions across membranes USING ENERGY (ATP)

• Example: Sodium-Potassium Pump

What if the molecules are too big?

• Move across the membrane by endocytosis or exocytosis

​

​It requires energy, so we still call it active transport.

Endocytosis

• Cell membrane folds in around a large particle and forms a small pouch

• The pouch then "pinches off" from the cell membrane to become a vesicle inside the cell

Exocytosis

• A vesicle moves to the cell membrane

• Fuses with cell membrane, and then releases its contents to the outside of the cell.

Multiple Choice

In PASSIVE TRANSPORT, substances move from:

• High concentration to low concentration

• Low concentration to high concentration

Multiple Choice

True or False:

In ACTIVE TRANSPORT, energy is not required.

• True

• False

Multiple Choice

Cells sometimes use energy to transport materials across the cell membrane.  This is called

• osmosis
• active transport

Multiple Choice

The roots of a plant contain a high concentration of minerals and the soil contains a lower concentration.  The roots absorb minerals from the low concentrated soil.  This is an example of

• passive transport.
• active transport.
• diffusion