Presentation on theme: "Material Flow in the Cell. Semipermeable Membrane The Cell Membrane is a Semipermeable membrane – it keeps some things out and lets some things in. Protects."— Presentation transcript:
Material Flow in the Cell
Semipermeable Membrane The Cell Membrane is a Semipermeable membrane – it keeps some things out and lets some things in. Protects contents of cell from outside world. Proteins are the bouncers
What Materials can Pass? What can come into the cell? Oxygen & food & proteins What goes out of the cell? Waste materials What is not allowed in? Poison and waste
PASSIVE TRANSPORT PASSIVE TRANSPORT – ways to move material into and out of the cell without using any energy. 2 Ways: 1. DIFFUSION 2. OSMOSIS – a type of diffusion
DIFFUSION The main method by which small molecules move across the cell membrane. The molecules move from an area of HIGHER CONCENTRATION to an area of LOWER CONCENTRATION. Oxygen molecules commonly move into and out of the cell by Diffusion. USES NO ENERGY (passive transport)
BEFOREAFTER DIFFUSION DEMO
BEFORE AFTER DIFFUSION
What Causes Diffusion? Molecules are always moving and they bump into each other. When they bump into each other they push each other away and spread out. Eventually they spread throughout the whole area. NO ENERGY NEEDED by cell because the molecules have energy in their vibrations.
OSMOSIS A special kind of diffusion The diffusion of water molecules through the cell membrane. Water still moves from HIGHER CONCENTRATION to LOWER CONCENTRATION. USES NO ENERGY (passive transport)
NORMAL RED BLOOD CELL OSMOSIS
BEFORE RED BLOOD CELL
POTATO FISH!!!! 1.Take out a sheet of paper! 2.Write down observations of both of your potato slices. 3.Put your name on both cups 4.Label one cup SALT and one cup FRESH 5.Put the same amount of water in each cup 6.Put salt in the cup that is labeled salt (amount does not matter, just make sure it dissolves!) 7.Put one potato slice in the FRESH cup and one in the SALT cup 8.We are going to leave the potatoes in their cups over night. 9.Write down your predictions. WHAT DO YOU THINK WILL HAPPEN TO EACH OF THE POTATOES?
ACTIVE TRANSPORT Active Transport – USES ENERGY to move materials into and out of the cell. Often from LOW concentration to HIGH concentration For small or large particles This requires the cell to USE ENERGY. 2 ways: 1.ENDOCYTOSIS 2.EXOCYTOSIS
ENDOCYTOSIS USES ENERGY (active transport) Large particles are taken INTO THE CELL Particles include PROTEIN and FOOD
ENDOCYTOSIS – draw these steps A WANTED MOLECULE 1 STEP 1: The cell membrane touches the wanted molecule. energy
ENDOCYTOSIS 2 STEP 2: The cell wraps itself around the molecule. energy
ENDOCYTOSIS 3 STEP 3: The molecule forms a Vacuole. energy
ENDOCYTOSIS 4 STEP 4: The cell membrane closes. energy
TRANSPORT PROTEINS These are special Proteins called Transport Proteins that are attached to the cell membrane. They PICK UP the wanted molecules inside or outside of the cell and carry them in or out using energy. Common Materials transported this way: –Calcium, Potassium, and Sodium.
TRANSPORT PROTEINS BEFORE CYTOPLASMOUTSIDE THE CELL HIGHLOW CONCENTRATION TRANSPORT PROTEIN
TRANSPORT PROTEINS AFTER USES ENERGY CYTOPLASMOUTSIDE THE CELL HIGHLOW CONCENTRATION