Lecture: Plasma Membrane and Transport I. Structure of the Plasma Membrane A. plasma membrane - the surface encapsulating a cell B. Fluid Mosaic Model 1. bilayer of phospholipids a. hydrophilic heads - P04 end "water" "loving" attracted to water on inner/outer parts of cell b. hydrophobic tails - fatty acids "water" "fearing" attracted to each other on inside of bilayer c
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Membrane Behavior Lab Abstract: Introduction: The permeability of a cell to solutes in an aqueous medium depends upon the physical and chemical make–up of the membrane. The maintenance of the living cell depends upon the continued presence and functioning of a selectively permeable membrane. If the nature of the membrane is changed or altered in any way‚ this may well affect its permeability and thus the properties of the cell of which it is a part. Irreversible changes in the permeability
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PLASMA MEMBRANE SELECTIVE PERMEABILITY= allowing some substance to cross it more easily than others composed of: Phospholipids Proteins Carbohydrates Cholesterol FLUID MOSAIC MODEL Phospholipids are primary lipids(constantly moving‚ fluidly) AMPHIPATHIC-containing hydrophobic and hydrophilic regions Mosaic part=not made of one thing Freeze-fracture studies:way to view what’s inside FLUIDITY OF MEMBRANE Move within bilayer Most of lipids and some proteins‚ drift laterally
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Cells‚ Cell Division‚ and Cell Specialization Fundamentally Different Types of Cell Prokaryotic Cell- single celled: only DNA+ structure (“before nucleus”) E.g. zygote-complete DNA Eukaryotic Cell-multi-celled (“after nucleus”) Prokaryotes Eukaryotes DNA In “nucleoid” region Within membrane-bound nucleus Chromosomes Single‚ circular Multiple‚ linear Organelles None Membrane-bound organelles Size Usually smaller Usually larger- 50 times Organization Usually single-celled Often multicellular
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Membrane Transport Process Process Energy Source Description Examples Passive processes Simple diffusion Kinetic energy Kinetic energy Net movement of particles (ions. molecules. etc.) from an area of their higher concentration to an area of their lower concentration. that is. along their concentration gradient Movement of fats‚ oxygen‚ carbon dioxide through the lipid portion of the membrane‚ and ions through protein channels under certain conditions Osmosis Kinetic energy Simple diffusion
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Bacteria Bacteria are microscopic organisms whose single cells have neither a membrane-enclosed nucleus nor other membrane-enclosed organelles like mitochondria and chloroplasts. Another group of microbes‚ the archaea‚ meet these criteria but are very different from the bacteria in other ways. In fact‚ there is considerable evidence that you are more closely related to the archaea than they are to the bacteria! Bacteria are living things that are neither plants nor animals‚ but belong to a group
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------------------------------------------------- The Utility and Disadvantages of Utilizing the Cellular Device at School August 18th‚ 2011 | Tags: cell phone‚ cellular‚ Communications‚ gadgets‚ mobile‚ technology‚ wireless Both teachers and authorities discouraged the use of Smart Phones in schools. The reason for this is the inattentiveness of the students during classes caused by the distractions these gadgets provide. Teachers do not appear to be aware of the benefits given by the different
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Membrane Transport Christopher Gaita‚ Deija Williams‚ Elisabeth Johnston & Megan Lade University of Phoenix (Online Campus) Amy Sullivan Introduction: Membrane Transport • What is membrane transport • Types – – – – Diffusion Osmosis Active Transport Endocytosis/Exocytosis Photo Courtesy Of: http://hyperphysics.phy-astr.gsu.edu/hbase/biology/celmem.html Osmosis • Example: A semipermeable membrane bag containing a 30% sugar solution is placed in a beaker of pure water. – Diffusion or osmosis
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Classification of Body Membranes Laszlo Vass‚ Ed.D. Version 42-0010-00-01 Lab repOrt assistant This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions‚ diagrams if needed‚ and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent
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3.1 BIOLOGICAL MEMBRANES 3.1.1 Properties of Cell Membranes • Separates living cell from its nonliving surroundings. • 8 nm thick. • Selectively permeable - allows some substances to cross more easily than others. 4.1.2 Fluid Mosaic Model • Singer and Nicolson (1972) - plasma membrane is a mosaic of proteins dispersed within lipid bilayer‚ with only bilayer‚ the hydrophilic regions exposed to water. Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein
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