Passive and Active transport

Passive and Active transport

How cells get the materials they need

Passive Transport

this is movement of molecules from high concentration to low concentration-----this is like going down a slide

Passive does NOT require energy!

Active transport

this is the movement of molecules from low concentration to high concentration---this is like running up a slide in the opposite direction

Active requires energy!

Poll

Which type of transport goes from high to low concentration?

• Passive

• Active

Cell Membrane

this is what allows for substances to move in and out of cells; it contains receptor proteins to "recognize" substances

Receptor Molecules

• they are proteins that are in the cell membrane

• they recognize, they receive, they respond

• Receptor begins with "r" just like recognize, receive and respond--any time you see receptor molecule you should think of these words

Poll

Where are the receptor molecules located?

• inside the cell

• in the cell membrane

• in the nucleus

The cell membrane is semi-permeable

• semi-permeable means that some things can go through the membrane while some things cannot

• this is also called "selectively permeable"

Semi-permeable membrane

the membrane allows substances through based on size and if the substances is recognized

Open Ended

What does semi-permeable mean?

Types of Passive Transport

• passive transport is called diffusion

• the diffusion of water is called osmosis

Osmosis

Osmosis is specifically the diffusion of water--meaning water moves from a high concentration to a low concentration

In this image, you can see that the water has moved from the left to right through the membrane

Open Ended

What is the diffusion of water called?

Water

• Water always wants to be equal inside and outside of a cell

• Water will move to make the amount equal

Active transport

• since this is movement from low to high (like going against a current), it requires energy

• the energy is called ATP (remember that ATP is made by cellular respiration in the mitochondria)

Active transport

Where there are more molecules, they will move where there are less and use energy to do so (as seen in the picture)

The blue circles represent the substance and it is moving from the top of the membrane through it to the other side

Poll

Which type of transport requires energy?

• diffusion

• passive transport

• active transport

• osmosis

Diffusion Through a Membrane

How substances move through cell membranes