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1、Cell Types Review and Plasma(cell)membrane,Section 2 Objectives page 175,Section Objectives,Identify the differences between eukaryotic and prokaryotic cells.Review the structure and function of the plasma membrane,Section 7.1 Summary pages 171-174,Cells that do not contain internal membrane-bound s
2、tructures are called prokaryotic cells.,The cells of most unicellular organisms such as bacteria do not have membrane bound structures and are therefore called prokaryotes.,Two Basic Cell Types,Section 7.1 Summary pages 171-174,Most of the multi-cellular plants and animals we know are made up of cel
3、ls containing membrane-bound structures and are therefore called eukaryotes.,Cells containing membrane-bound structures are called eukaryotic cells.,7.1,Two Basic Cell Types,Section 7.1 Summary pages 171-174,The membrane-bound structures within eukaryotic cells are called organelles.,Each organelle
4、has a specific function that contributes to cell survival.,Two Basic Cell Types,Section 7.1 Summary pages 171-174,The nucleus is the central membrane-bound organelle that manages cellular functions.,Separation of organelles into distinct compartments benefits the eukaryotic cells.,Two Basic Cell Typ
5、es,Section 1 Check,Plasma membrane,Nucleus,Nucleolus,Chromosomes,Organelles,Check-up:,What makes this cell eukaryotic?,A.Because it has membrane-bound organelles.,B.Because it does not have DNA.,Summary Section 2 pages 175-178,All living cells must maintain a balance regardless of internal and exter
6、nal conditions.Survival depends on the cells ability to maintain the proper conditions within itself.,Summary Section 2 pages 175-178,Why cells must control materials,The plasma membrane is the boundary between the cell and its environment.,Summary Section 2 pages 175-178,It is the plasma membranes
7、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.,Summary Section 2 pages 175-178,
8、This process of maintaining 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.,Summary Section 2 pages 175-178,Water,Plasma Membrane,Summary Section 2
9、pages 175-178,Structure of the Plasma Membrane,The plasma membrane is composed of two layers of phospholipids back-to-back.,Phospholipids are lipids with a phosphate attached to them.,Summary Section 2 pages 175-178,Makeup of the phospholipid bilayer,The phosphate group is critical for the formation
10、 and function of the plasma membrane.,Phosphate Group is polar like water.,The tails are non-Polar and do not Interact with water,Summary Section 2 pages 175-178,Makeup of the phospholipid bilayer,The fluid mosaic model describes the plasma membrane as a flexible boundary of a cell.The phospholipids
11、 move within the membrane.,Summary Section 2 pages 175-178,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.,CholesterolMolecule,Summary Section 2 pages 175-178,Other 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,知识就是财富丰富你的人生,
