Lecture_8_DulaiS09_Cells

Lecture_8_DulaiS09_Cells - BIS 1 Lecture 5 1 ecture 6...

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Unformatted text preview: BIS 1 Lecture 5 1 ecture 6 Agenda: Cells are ACTIVE, DYNAMIC entities what basic machinery (structure) gives rise to this activity? 3. What characteristics do all cells share? 4. What are prokaryotic cells? Eukaryotic cells? How are they similar? In what ways do they differ? 2. What is Cell Theory? What are the implications? Why is it important? 1. What are proteins? What determines how a protein works (functions)? Why are they so important? 5. What are the basic structures of prokaryotic and eukaryotic cells? BIS 1 Lecture 5 2 Cell structure & function Lecture 6 Chapter 4 BIS 1 Lecture 5 3 Fig. 4-1a, p.50 Animalcules (Robert Hooke, von Leeuwenhoek, late 1600s) BIS 1 Lecture 5 4 Fig. 4-2, p.51 Robert Hooke BIS 1 Lecture 5 5 What are cells? A cell is multiple molecules interacting in a specific, highly organized , way. Cells are structural units of organisms : organisms are made of at least one cell Cells are the smallest units of organization that display the properties of life - ALL LIFE IS CELLULAR Pear tissue Pear tissue BIS 1 Lecture 5 6 Cells differ in shape, size, and activities, but they all share three basic components Plasma membrane (also called cell membrane, or lipid bi-layer) Defines a cell as a distinct structural entity. Separates cells from their environment (in both multicellular and unicellular organisms) Permits flow of molecules across membrane Contains receptors that affect cell activities DNA-containing region Possibly within a nucleus (eukaryote/prokaryote) Cytoplasm Semi-fluid substance within the cell (excluding organelles, i.e., cell sub-compartments, and their contents) BIS 1 Lecture 5 7 DNA cytoplasm plasma membrane Fig. 4-3a, p.52 Prokaryotic and Eukaryotic Cells BIS 1 Lecture 5 8 DNA in nucleus plasma membrane cytoplasm Fig. 4-3c, p.52 rokaryotic and Eukaryotic Cells BIS 1 Lecture 5 9 A few words on the cell membrane Cytoplasm (aqueous solution) (aqueous solution) Cell membrane Given that the cytoplasm (as well as most extra-cellular environments) is an aqueous solution, would a cell membrane in sugar work? Why? Which property must the molecules of the cell membrane have? Which biomolecules could be used in the cell membrane? BIS 1 Lecture 5 10 Cell membranes are lipid bilayers (i.e., two layers of molecules)- The lipids of the cell membrane are phospholipids- They have a hydrophilic, polar head (with group phosphate) and two long, hydrophobic tails (aliphatic chains of C, with H)- The heads are dissolved in the aqueous fluids, and the hydrophobic tails are sandwiched between the polar heads One layer of phospholipids One layer of phospholipids BIS 1 Lecture 5 11 Protein pump across bilayer Protein channel across bilayer Protein pump Recognition protein extracellular environment cytoplasm Receptor protein lipid bilayer Fig. 4-5a, p.53 Plasma Membrane BIS 1 Lecture 5 12 Cells are traditionally divided into two fundamental types based on their organization Unicellular organisms...
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Lecture_8_DulaiS09_Cells - BIS 1 Lecture 5 1 ecture 6...

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