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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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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The plasma or cell membrane exhibits ability for the cell to discriminate in its chemical exchanges with its environment and this makes cell membrane fundamental to life. This property can only be possible because of the cell membrane’s selective permeability (Campbell and Reece‚ 2002). The structure of the membrane can be best illustrated by the fluid mosaic model where the membrane is said to be a fluid structure with various proteins embedded in or attached to a bilayer of phospholipids (Campbell
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Temperature on Membrane Permeability of Beetroot Name: Ghazal Daneshfar E-mail: GDANES200@caledonian.ac.uk Student ID: S1312108 INTRODUCTION The cell membrane consists of mostly phospholipids and proteins which gives the cell its selectively permeable nature. The function and permeability of the cell membrane depends on its whole structure. When destroyed‚ the permeability of the cell membrane is disrupted causing cellular contents to leak out. When cells are cut‚ the cell membranes are mechanically
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BIOL 3810-504 Compound Action Potentials Date Performed: 15FEB2011 Date Due: 01MAR2011 Introduction Neurons are the cells that receive and transmit electrical signals (University of North Texas‚ 2010). The ability of the neuron to conduct these impulses is because of an electrochemical voltage across the plasma membrane of that neuron. An action potential is an all or nothing response to a stimulus along a single axon. A compound action potential is a graded response that results from
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The Semipermeability of Cell Membrane to Different Osmotic Environments Using Dialyzing Bag Model1 Sittie Johaynnah M. Sambarani Group 3 Sec. I-1L December 17‚ 2012 ------------------------------------------------- ------------------------------------------------- ------------------------------------------------- ------------------------------------------------- 1 A scientific paper in partial fulfillment of the requirements in Biology 10 Laboratory under Professor Junaldo
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Cell Membranes and Transport Hands-On Labs‚ Inc. Version 42-0033-00-01 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
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stress that various alcohols have on biological membranes. Using five solutions of differing alcohol concentration for each of the three alcohols; methanol‚ ethanol‚ and 1-propanol and a small slice of beet‚ the stirred solution was placed into a plastic cuvette and then into a spectrophotometer and the absorbance of alcohol solutions were determined in order to conclude which alcohol and concentration of alcohol had the greatest effect on biological membranes. The results showed that the most non-polar
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MOVEMENT ACROSS MEMBRANES Intracellular fluid Extracellular fluid Pond water Blood plasma K+ A- ClNa+ Cl+ K+ Na+ Cl- Na+ Na+ Gill epithelial cell Intestinal epithelial cells Cl- Cell membrane Anionic proteins (a) Ion concentration inside a single animal cell (b) Ion concentration across gill epithelium of a freshwater fish Blood capillary Intestinal lumen Glucose from meal Cross section of small intestine (c) Glucose transport across intestinal epithelium into
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What Causes the Resting Tremor in Parkinson’s Disease? Resting Tremor Is Characteristic Of Parkinson’s Disease. For three out of every four people who develop Parkinson’s disease(PD)‚ the disease begins with a trembling or shaking in one of the hands. It can also appear in the feet‚ face or jaw but usually it appears in one of the hands. This tremor happens when the muscles of the hands are relaxed and at rest. Hence the name: resting tremor. Tremor Has a ’Pill-Rolling’ Quality The tremor usually
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