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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you be able to observe any diffusion? No 5. Does being unable to observe diffusion necessarily mean that diffusion is not taking place? It can still take place due to molecules moving all the time due to the mixture of concentration. Osmosis Activity 4: Osmosis 1. Did you observe any pressure changes during the experiment? If so‚ in which beaker(s)‚ and with which membranes? Pressure changed in the left beaker with 20 MWCO 2. Why? Lower number in molecules moving around 3. Did the Na+/Cl-
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PhysioEx™ Lab: Cell Transport Mechanisms and Permeability Activity 1: Simple Diffusion Chart 1 Dialysis Results (Average Diffusion rate in mM/min) Solute Membrane (MWCO) 20 50 100 200 NaCl (—) 0.0150 0.0150 0.0150 Urea (—) (—) 0.0094 0.0094 Albumin (—) (—) (—) (—) Glucose (—) (—) (—) 0.0040 1) Which solute(s) were able to diffuse into the right beaker from the left? NaCl‚ Urea‚ Glucose 2) Which solute(s) did not diffuse? Albumin 3) If the solution in the left beaker
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& exocytosisDiffusion‚ facilitated diffusion‚ and osmosis. Types of Particles Transported proteins‚ ions‚ large cells‚ complex sugars. Anything soluble (meaning able to dissolve) in lipids‚ small monosaccharides‚ water‚ oxygen‚ carbon dioxide‚ sex hormones‚ etc. Examples phagocytosis‚ pinocytosis‚ sodium/potassium pump‚ secretion of a substance into the bloodstream (process is opposite of phagocytosis & pinocytosis) diffusion‚ osmosis‚ and facilitated diffusion. Importance In eukaryotic
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more permeable to water. When ADH is increased in the blood flow‚ more water-permeable channels are inserted‚ allowing more water to be reabsorbed by osmosis into the blood stream. When this happens‚ less urine‚ of a much lowered water potential‚ passes out of the body. This suggests that due to the cell walls being more permeable to water and also osmosis reabsorbing the water‚ this in turn lead to Leah’s water intoxication‚ as it was stored in the body opposed to leaving it correctly. Consequently
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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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occurs when solutes are transferred from a high concentration of that solute to a lower concentration of solutes. Solutes do not depend on the concentration of other solutes‚ which allows the cell to take in oxygen while releasing carbon dioxide. Osmosis is a special type of diffusion‚ which occurs when water is diffused across the membrane. This can be affected by how hydrophilic a solute is on either side of the membrane. The diffusion of glucose‚ starch‚ and iodine was observed when the solutes
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Investigating the water potential of a potato Aim Osmosis is the movement of water molecules from a region of high water concentration to a low water concentration through a semi-permeable membrane. Our aim is to investigate the water potential of a potato through osmosis‚ by finding the difference in weight before and after the potato has been set in a solution of water‚ sugar or salt. Trial Method Firstly we collected the equipment. This included a scalpel‚ potato cutter‚ and test tubes. Then
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cell and because of that the water potential outside the cell would be lower than inside the cell. This would cause water (turgor pressure) to be lost by Osmosis. Osmosis is the net movement of water from high pressure to low pressure across a partially permiable membrane and it is that reason that it requires no energy for the movement. Osmosis eventually stops/slows down when water pressure has become balanced out between the “movements”. Planning & Implementing In this study I will use different
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Physioex 9.0 Review Sheet Exercise 1 Cell Transport Mechanisms and Permeability Name: Jeffery Cook Lab Time/Date: 12pm 2/09/2015 Activity 1 Simulating Dialysis (Simple Diffusion) 1. Describe two variables that affect the rate of diffusion. a. Two variables that affect the rate of diffusion are size and whether or not there is an electrical or concentration gradient. 2. Why do you think the urea was not able to diffuse through the 20 MWCO membrane? How well did the results compare with your prediction
Free Diffusion Molecular diffusion Sodium chloride