Cell Structure and Function - The Cell in Its Environment

Do Now: How is the cell membrane shown below like a colander?

Homework:

1.The cell in its environment worksheet

2.Mini Quiz Wednesday October 3rd.

2. Test on Wednesday, October 10th.

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Cell Structure and Function

•Cell membrane is selectively permeable- -some substances can pass through, while others cannot.

Permeable to: oxygen, water, carbon dioxide

Not permeable (impermeable) to: large molecules and salts

Cell Structure and Function

There are three methods by which substances move into and out of the cell:

diffusion, osmosis or active transport

Cell Structure and Function1) DIFFUSION: the process by which molecules move from an area of higher concentration to an area of lower concentration (high concentration--> low concentration)

Demonstration: air freshenerExample in text: page 41 unicellular organism in pond water.. 

Cell Structure and Function

2)OSMOSIS: diffusion of water molecules through a selectively permeable membrane, from high to low concentration.

Demo: Raisins in water

Example in text: Page 42 red blood cell

Cell Structure and Function - The Cell in Its Environment

Cell Structure and Function - The Cell in Its Environment

Concentration of water is the same inside the cell as it is outside the cell

What happened to the cell? It stays the same size

Cell Structure and Function

Concentration of water is lower outside the cell.

What happened to the cell? It will shrink/shrivel

Cell Structure and Function

Concentration of water is higher outside the cell.

What happened to the cell? It will expand or even explode

Cell Structure and Function

3) ACTIVE TRANSPORT: the movement of materials through a cell membrane using energy (low high concentration)

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Cell Structure and Function

The movement through a cell membrane without using energy is called passive transport

The main difference between active transport and passive transport is:

For active transport the cell must use energy.

For passive transport the cell does not use energy.

Cell Structure and Function - The Cell in Its Environment

Active Transport takes materials from a low concentration to a high concentration.

There are transport proteins that help this happen and these transport proteins require energy to work.

Cell Structure and Function

What will be on the test?

Characteristics of Living Things

Needs of Living Things

The experiments: Is it a living thing lab, understand Redi and Pasteur concepts.

Cell Theory

Cells and their organelles

Cell Transport (diffusion, osmosis and active transport)

Cell Structure and Function

BrainPOP