Cell Membrane - CELL MEMBRANES 1 Roles of cell membranes 2 Roles of cell membranes The cell membrane(aka Plasma Membrane is a double layer of lipids

Cell Membrane - CELL MEMBRANES 1 Roles of cell membranes 2...

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CELL MEMBRANES
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1. Roles of cell membranes 2
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Roles of cell membranes The cell membrane (aka Plasma Membrane), is a double layer of lipids and proteins that surrounds a cell and separates the cytoplasm (the contents of the cell) from its surrounding environment. The cell membrane is selectively permeable, which means that it only lets certain molecules (ex. Oxygen, nutrients) to enter and exit (ex. waste) through diffusion and active transport. It can also control the amount of some substances that go into or out of the cell. 3
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Roles of cell membranes Cell membranes act as a barrier between the cell and the organelles inside it, from the cytoplasm outside of it. This allow metabolic reactions to occur inside of the cell without interference from outside of the cell. (Isolate enzymes that might damage cell, ex. lysozymes) The cell membrane can also act as a “skeleton” in some organisisms and help maintain the shape of the cell. 4
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Roles of cell membranes The cell membrane also plays a role in cell signaling and communication. Receptor proteins on the cell membrane can bind to molecules produced by other areas of the body (ex.hormone). When a molecule binds to its target receptor on the membrane, it initiates a signal to the inside of a cell for the action to be done. 5
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Roles of cell membranes The cell membrane is also responsible to regulate how big the cell gets. Through endocytosis and exocytosis, the cell increase and decreases in size to suit its needs. In endocytosis, lipids and proteins are removed from the cell membrane to shrink in size. In exocytosis, vesicles containing lipids and proteins fuse with the cell membrane to expand in size.
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  • Fall '11
  • CarolYeung

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