Warm-UP

1. What are the two major types of cell transport (CT), and what distinguishes them from each other?

2. What type of CT is each of the following: diffusion, active transport, endocytosis, osmosis, and exocytosis?

Try It

With a partner…grab a mini white board (and a WB marker) and design an illustration that explains one type of active or passive transport…be creative!

Your GA Standards are…

S7L2. Students will describe the structure and function of cells, tissues, organs, and organ systems.

Element: S7L2.a

Explain that cells take in nutrients in order to grow and divide and to make needed materials.

Element: S7L2.d

Explain that tissues, organs, and organ systems serve the needs cells have for oxygen, food, and waste removal.

Your Essential Questions are…

1. What sort of “stuff” moves into and out of cells?

2. Why is the movement of this “stuff” crucial to the survival of an organism?

3. How does this stuff get in there…or out of there?

What Do Cells Do

Anyway? Ok…now you know what classifies something as

“LIVING;” what all living things need; and all about cell theory…what exactly

is going on inside of those cells? You’re not

writing all of this down…are you?

How Do Substances Get In and

Out of Cells?

The first thing to understand is that the cell membrane is what controls what goes in and out of cells.

It can do this because it is…get ready for a big word…SELECTIVELY PERMEABLE.

Selective…as in…its choosey

Permeable…as in…stuff can go through it…but only certain stuff.

This is a chemical choosiness.

Here’s Something You Need to

Understand…

Substances (stuff) naturally move from HIGH CONCENTRATRION to LOW.

This is because atoms and molecules are always moving and bumping into each other. If its hot they move faster; If its cooler they move more slowly.

As they collide (bump), they keep spreading out until they’re evenly distributed aka…EQUILIBRIUM (that’s a sciency word for evenly spread out).

Two Main Processes…and their

friends

1. Passive Transport- requires NO ENERGY input.

Diffusion: molecules move from high concentration (a lot of stuff) to low concentration (less stuff).

Osmosis: a special type of diffusion in which water and a semi-permeable membrane are involved.

Facilitated Diffusion: some stuff just can’t get through the membrane without a little help. Carrier molecules (permeases) are happy to lend a hand.

2. Active Transport-REQUIRES ENERGY. Involves movement of molecules from low concentration (less stuff) to high concentration (a lot of stuff). And that ain’t easy!

Endocytocis, aka Engulfing (phagocytosis/pinocytosis): the cell membrane “swallows” an outside particle and pinches off. This forms a vacuole.

Exocytosis…a vesicle forms around an

unwanted molecules, attaches to the cell membrane, and…out it goes.