Cell Transport Notes (pp.33-37) Copy the words seen in red onto your note sheet.

Cell Membrane Review - ALL cells have a cell membrane made of proteins and lipids - SOME cells have cell membranes and cell walls (plants, fungi and bacteria) Cell Membrane Cell Wall The cell membrane is selectively permeable which allows certain substances such as oxygen, water, food molecules, carbon dioxide, and waste products to move into and out of the cell.

Cell Transport Materials move into and out of cells through either passive transport or active transport. Analogies for the 2 Types of Cell Transport Analogy: Child is sitting on swing and hoping that the swing will move without assistance. Analogy: Child is being pushed on the swing by a helper.

(A) PASSIVE TRANSPORT- NO ENERGY NEEDED: (1) Process of Diffusion (2) Process of Osmosis (B) ACTIVE TRANSPORT- ENERGY NEEDED: (1) Help of Transport Proteins (2) Process of Engulfing (or “Cell-Eating”) Another Analogy for 2 Types of Cell Transport: This was today’s LL question!

(A) PASSIVE TRANSPORT Molecules move from a more crowded to a less crowded area to reach a balance, or homeostasis, (equal amounts of the substance on both sides of the membrane). NO ENERGY is required. Two Types of Passive Transport: (1)Diffusion (2)Osmosis

(1) DIFFUSION Molecules (small particles) move from a more crowded area to a less crowded area. How does diffusion work? Molecules bump into one another as they move and these collisions push the molecules away from each other. The more collisions, the more spread out the molecules become until they eventually reach equilibrium (or homeostasis).

How does diffusion work? Molecules bump into one another as they move and these collisions push the molecules away from each other. The more collisions, the more spread out the molecules become until they eventually reach equilibrium (or homeostasis).

(2) OSMOSIS A special type of diffusion: Diffusion of water through a selectively permeable membrane from a more crowded area to a less crowded area On the left, the water concentration was high at the start so the flow of water moved to the right. The selectively- permeable membrane allows water to pass, but not sugar.

Now you try (before and after diffusion) Diagram A: The oxygen molecules ( ) inside and outside the cell are shown before diffusion. Diagram B: You draw how the oxygen molecules would be distributed AFTER diffusion has occurred. If each molecule ( )was a molecule of water (instead of oxygen), could this diagram be illustrating osmosis? Explain why or why not. (Remember there are two conditions needed for osmosis) _____________________________ ______________________________________________________________

Now you try - ANSWER (before and after diffusion) Diagram A: The oxygen molecules ( ) inside and outside the cell are shown before diffusion. Diagram B: You draw how the oxygen molecules would be distributed AFTER diffusion has occurred. If each molecule ( )was a molecule of water (instead of oxygen), could this diagram be illustrating osmosis? Explain why or why not. (Remember there are two conditions needed for osmosis) Yes! Osmosis is the movement of water through a membrane from high to low concentration so the requirements would be met.

(B) ACTIVE TRANSPORT Molecules move from a less crowded to a more crowded area WITH the use of ENERGY. Molecules are "carried" into or out of the cell using some of the cell's energy. Two Types of Active Transport: (1) Transport Pumps (2) Engulfing (or “Cell-Eating”)

Example of a cell’s need for active transport: Body cells must pump carbon dioxide out into the surrounding blood vessels to be carried to the lungs for exhale. Blood vessels are high in carbon dioxide compared to the cells, so energy is required to move the carbon dioxide across the cell membrane from LOW to HIGH concentration. outside of cell inside of cell Carbon Dioxide molecules

(1) TRANSPORT PROTEINS Proteins or Pumps are found in the cell membrane. They transport molecules across the membrane. ATP = Energy

(2) ENGULFING or “Cell-Eating” The cell membrane surrounds the particle and takes it in. The cell membrane forms a vacuole around the particle. Food is moved into the cell by Endocytosis Wastes are moved out of the cell by Exocytosis

Ex: Amoebas use this process to eat. Ex: White Blood Cells, which are part of the immune system, surround and engulf bacteria.