Cell Membrane Cell Transport Think of our cells

Cell Membrane & Cell Transport

Think of our cells as a city. Do you think that our cells need imports and make exports?

Remember this? ? ? Glucose Oxygen Carbon Dioxide Water

How do things get in and out of the cell? The cell membrane regulates what goes in and out of our cells!

The cell membrane is like a ticket taker, it controls what can go in and out of the cell.

What is the cell membrane made of? The cell membrane is a phospholipid bilayer.

Phospholipid Phosphate heads Lipid Tails

Hydrophillic Hydrophobic Phosphate Heads Lipid tail

A Model Cell Membrane

What characteristic of the cell membrane was modeled when you formed an opening in the bubble membrane with the rubberband then removed it?

What characteristic was modeled when the bubble membrane burst if a dry object was inserted but not when an object coated with bubble solution was inserted?

What happened when you put the bubble coated straw through the membrane?

Membrane proteins create a path for unlike molecules to pass through the plasma membrane and enter the cell.

We know that things move in and out of our cells, but how do they do it?

Passive Transport transport of molecules across a membrane that does not require energy Happens because of concentration gradients! (high to low!)

There are 2 types of passive transport: 1. Diffusion 2. Osmosis

Diffusion Movement from _______ high concentration to ______ low concentration.

Only water passed through the cell membrane.

Osmosis the diffusion of water

Which side has more particles? B So which side needs to be diluted? (add more water to it) B There needs to be more water on side B, because there are more particles

Water will move to side ___ A Why? Because it has more particles and needs to be diluted

Does changing the amount of water in the cell change the size of the cell?

Isotonic There is an equal concentration of dissolved material inside and outside of the cell.

When there is a large amount of solutes outside of the cell does the cell get bigger, smaller, or stay the same?

Hypertonic The concentration of dissolved material is higher outside the cell than inside the cell

When the amount of solutes outside of the cell decreases does the cell get bigger, smaller, or stay the same?

Hypotonic The concentration of dissolved material is lower outside the cell than inside the cell

What would happen if we put the animal cell in pure water?

Turgor Pressure water pressure in the plant cell that causes the cell membrane to press against the cell wall

Plasmolysis loss of water from a plant cell, causing pressure to drop in the cell and the cell membrane will shrink and pull away from the cell wall

Let’s Recap! Type of PASSIVE TRANSPORT Description Diffusion Movement from HIGH concentration to LOW concentration Osmosis Movement of water from HIGH concentration to LOW concentration (the diffusion of water)

Active Transport transport of molecules across a membrane that requires energy Why do you think it requires energy?

This requires energy because it is moving particles from LOW to HIGH concentration!

A B Which way would the particles flow if it was passive transport? Side B Which way would the particles be pumped if it was active transport? Side A If active transport was used, would the 2 sides be in equilibrium? NO