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Cell Processes I. Passive Transport. Healthy Cell. 70% water 15% protein 10% fat 4% DNA and other materials 1% carbohydrate. How do cells get what they need?. Passively – certain materials go in and out of the cell through the cell membrane with out using any energy
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Cell Processes I Passive Transport
Healthy Cell • 70% water • 15% protein • 10% fat • 4% DNA and other materials • 1% carbohydrate
How do cells get what they need? • Passively – certain materials go in and out of the cell through the cell membrane with out using any energy • Actively – energy is required to bring nutrients into the cell and energy is required to eliminate wastes from the cell
Two Methods cells use to get what they need Passive Transport – does not require energy Active Transport – does require energy
Types of Passive Transport • Simple diffusion • Facilitated diffusion • Osmosis
Simple diffusion • Simple Diffusion – When substances (particles or molecules)move from a an area of high concentration to an area of low concentration across a selective semi permeable membrane without any trouble or interference
What is a selectively permeable membrane? • It let’s certain materials in or out of the cell but not others. It’s particular!
Facilitated diffusion • Molecules that have a certain chemical make up look for a doorway or channel so they can get in or out of the cell without using energy • These doorway channels are selective in what they let in and out of the cell
Osmosis • The diffusion of water only • The rate of diffusion of water is dependent on temperature, pressure, and the concentration of other substances like salt
Equilibrium is the goal of Passive Transport • When the concentration of the diffused particles is the same on both sides of the semi permeable membrane • The inside of the cell has the same concentration of diffused materials as the outside of the cell
Questions…. • Why is it important to keep the right balances of water, oxygen, protein, carbohydrate and fats outside the cell? • How do we do this?
Cell Processes II Active Transport
What does a cell do if…. • It is in equilibrium but it still needs more diffusible materials? • It needs nutrients that are too large to passively go through the cell membrane? • It needs to get rid of wastes that are too large to passively leave the cell?
Active transport • When substances move from an area of low concentration to high concentration • This does require energy! • ATP is the carrier molecule that provides the energy necessary for active transport to occur • Draw this!
Endocytosis • When the cell needs particles that are too large and cannot pass through the semi permeable membrane – endocytosis
Exocytosis • When the cell wants to get rid of particles that are too large to pass through the semi permeable membrane - exocytosis