Cell Transport Membrane Structure Describe passive transport Describe
Cell Transport - Membrane Structure - Describe passive transport. -Describe active transport.
Cell Membrane (aka Phospholipid Bilayer, Lipid Bilayer and Plasma Membrane)
Types of Passive Transport 1. Diffusion 2. Facilitated Diffusion 3. Osmosis Passive Transport requires NO ENERGY. Molecules move down their concentration gradient. HIGH to LOW concentration.
Diffusion The movement of particles from an area of high concentration to an area of low concentration is DIFFUSION.
Facilitated Diffusion Cell membranes have proteins that act as carriers, or channels, making it easy for certain molecules to cross. Molecules that cannot directly diffuse across the cell membrane pass through special protein channels in a process known as facilitated diffusion.
Osmosis The movement of WATER MOLECULES from an area of high concentration to an area of low concentration is called osmosis.
Types of Active Transport 1. Endocytosis a. Pinocytosis b. Phagocytosis 2. Exocytosis 3. Sodium-Potassium Pump Active transport requires ENERGY. Cells sometimes must move materials AGAINST a concentration gradient. LOW to HIGH concentration.
Endocytosis is the process of taking material into the cell. Two types of endocytosis are: 1. Pinocytosis – cell “drinking” 2. Phagocytosis – cell “eating”
Exocytosis When material is RELEASED from the cell, a process known as exocytosis.
Sodium Potassium Pump Sometimes pumps are needed to force molecules to move AGAINST their concentration gradient (from an area of LOW to HIGH concentration). The sodium potassium pump is used ESPECIALLY in the nervous and muscular systems.
Movement across cell membranes affects the cell itself… Different types of environments exist for the cell based on the concentration of substances inside and outside of the cell. These include Hypertonic, Hypotonic and Isotonic environments. An ISOTONIC environment is the ideal and needed to maintain homeostasis.
Isotonic Solution Concentration is EQUAL inside and outside of the cell.
Hypotonic Solution Concentration is higher INSIDE the cell. Water ENTERS the cell. The cell swells and may, ultimately, burst or lyse.
Hypertonic Solutions Concentration is higher OUTSIDE the cell. Water LEAVES the cell. Cell SHRIVELS up from water loss.
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