1、Cell Types Review and Plasma (cell) membraneSection Objectives Identify the differences between eukaryotic and prokaryotic cells. Review the structure and function of the plasma membrane Cells that do not contain internal membrane-bound structures are called prokaryotic cells. The cells of most unic
2、ellular organisms such as bacteria do not have membrane bound structures and are therefore called prokaryotes.Two Basic Cell Types Most of the multi-cellular plants and animals we know are made up of cells containing membrane-bound structures and are therefore called eukaryotes. Cells containing mem
3、brane-bound structures are called eukaryotic cells.7.1Two Basic Cell Types The membrane-bound structures within eukaryotic cells are called organelles. Each organelle has a specific function that contributes to cell survival.Two Basic Cell TypesThe nucleus is the central membrane-bound organelle tha
4、t manages cellular functions. Separation of organelles into distinct compartments benefits the eukaryotic cells.Two Basic Cell TypesPlasma membraneNucleusNucleolusChromosomesOrganellesCheck-up: What makes this cell eukaryotic?A. Because it has membrane-bound organelles. B. Because it does not have D
5、NA. All living cells must maintain a balance regardless of internal and external conditions. Survival depends on the cells ability to maintain the proper conditions within itself.Why cells must control materials The plasma membrane is the boundary between the cell and its environment. It is the plas
6、ma membranes job to: allow waste and other products to leave the cell. remove excess amounts of these nutrients when levels get so high that they are harmful. allow a steady supply of glucose, amino acids, and lipids to come into the cell no matter what the external conditions are. This process of m
7、aintaining the cells environment is called homeostasis. Selective permeability is a process used to maintain homeostasis in which the plasma membrane allows some molecules into the cell while keeping others out.WaterPlasma MembraneStructure of the Plasma Membrane The plasma membrane is composed of t
8、wo layers of phospholipids back-to-back. Phospholipids are lipids with a phosphate attached to them.Makeup of the phospholipid bilayer The phosphate group is critical for the formation and function of the plasma membrane.Phosphate Group is polar like water.The tails are non-Polar and do not Interact
9、 with waterMakeup of the phospholipid bilayer The fluid mosaic model describes the plasma membrane as a flexible boundary of a cell. The phospholipids move within the membrane.Other components of the plasma membrane: Cholesterol plays the important role of preventing the fatty acid chains of the phospholipids from sticking together it gives it strength.CholesterolMoleculeOther components of the plasma membrane: Transport proteins allow needed substances or waste materials to move through the plasma membrane.Click image to view movie.谢谢你的阅读v知识就是财富v丰富你的人生
