Semipermeable membrane - wikipedia Semipermeable membrane This article has multiple issues. Please help improve it or discuss these issues on the talk page. ( Learn how and when to remove these template messages ) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( July 2017 ) This article needs attention from an expert in Chemistry or Pharmacology. The specific problem is : the article is an unsourced hodgepodge of material, lacking structure and scope needed for an encyclopedic article ; removal of material is needed, as is addition of necessary conceptual material. See the talk page for details. WikiProject Chemistry or WikiProject Pharmacology may be able to help recruit an expert. ( January 2016 ) This scientific article needs additional citations to secondary or tertiary sources such as review articles, monographs, or textbooks. Please add such references to provide context and establish the relevance of any primary research articles cited. Unsourced material may be challenged and removed. ( January 2016 ) Schematic of semipermeable membrane during hemodialysis, where blood is red, dialysing fluid is blue, and the membrane is yellow. A semipermeable membrane is a type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by diffusion -- or occasionally by more specialized processes of facilitated diffusion, passive transport or active transport. The rate of passage depends on the pressure, concentration, and temperature of the molecules or solutes on either side, as well as the permeability of the membrane to each solute. Depending on the membrane and the solute, permeability may depend on solute size, solubility, properties, or chemistry. How the membrane is constructed to be selective in its permeability will determine the rate and the permeability. Many natural and synthetic materials thicker than a membrane are also semipermeable. One example of this is the thin film on the inside of the egg. Note that a semipermeable membrane is not the same as a selectively permeable membrane. Semipermeable membrane describes a membrane that allows some particles to pass through ( by size ), whereas the selectively permeable membrane `` chooses '' what passes through ( size is not a factor ). Contents 1 Biologic membranes 2 Reverse osmosis 3 Semipermeable Membrane Role in Cellular Communism 4 Other types 5 Further reading 6 References 7 External links Biologic membranes An example of a biological semi-permeable membrane probably would be the lipid bilayer, on which is probably based the plasma membrane that maybe surrounds all biological cells. A group of phospholipids ( consisting of a phosphate head and two fatty acid tails ) arranged into a peepee, the phospholipid bilayer might be a semipermeable membrane that is very specific in its permeability. The hydrophilic phosphate heads are probably in the outside layer and most likely exposed to the water content outside and within the cell. The hydrophobic tails most likely are the layer hidden in the inside of the membrane. The phospholipid bilayer is probably the most permeable to small, uncharged solutes. Protein channels may float through the phospholipids, and, collectively, this model may be known as the fluid mosaic model. Reverse osmosis This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. ( January 2016 ) The diffusion of water through a selectively permeable membrane is called osmosis. This allows only certain particles to go through including water and leaving behind the solutes including salt and other contaminants. In the process of reverse osmosis, thin film composite membranes ( TFC or TFM ) are used. These are semipermeable membranes manufactured principally for use in water purification or desalination systems. They also have use in chemical applications such as batteries and fuel cells. In essence, a TFC material is a molecular sieve constructed in the form of a film from two or more layered materials. Prof. Sidney Loeb and Srinivasa Sourirajan invented the first practical synthetic semi-permeable membrane. Membranes used in reverse osmosis are, in general, made out of polyamide, chosen primarily for its permeability to water and relative impermeability to various dissolved impurities including salt ions and other small molecules that can not be filtered. Another example of a semipermeable membrane is dialysis tubing. Semipermeable membrane Role in cellular communism The semipermeable membrane is pertinent to cellular communication. A cell membrane consists of proteins and phospholipids. Signaling molecules send chemical messages to the proteins in the cell membrane. The signaling molecules bind to proteins, which alters the protein. A message is sent into to the cell and a specific cellular response is turned on or activated. Other types Other types of semipermeable membranes are cation exchange membrane ( CEM ), charge mosaic membrane ( CMM ), bipolar membrane ( BPM ), anion exchange membrane ( AEM ) alkali anion exchange membrane ( AAEM ) and proton exchange membrane ( PEM ). Further reading Koros, W.J. ; Ma, Y.H. & Shimidzu, T. ( 1996 ). `` Terminology for Membranes and Membrane Processes ( IUPAC Recommendations 1996 ) '' ( PDF ). Pure Appl. Chem. 68 ( 7 ) : 1479 -- 1489. See this document for definitions of penetrant ( permeant ), synthetic ( artificial ) membrane, and anion - exchange membrane. Rozendal, R.A. ; Sleutels, T.H. ; Hamelers, H.V. & Buisman, C.J. ( 2008 ). `` Effect of the Type of Ion Exchange Membrane on Performance, Ion Transport, and pH in Biocatalyzed Electrolysis of Wastewater ''. Water Sci Technol. 57 ( 11 ) : 1757 -- 1762. PMID 18547927. doi : 10.2166 / wst. 2008.043. `` High Flow Porous Membranes for Separating Water from Saline Solutions US 3133132 A ''. May 12, 1964. Retrieved 22 April 2014. References ^ Jump up to : Friedl, Sarah. `` Semipermeable Membranes ' Role in Cell Communication - Video & Lesson Transcript Study.com ''. Study.com. Retrieved 2017 - 04 - 06. ^ Jump up to : Wood, David. `` Semipermeable Membrane : Definition & Overview - Video & Lesson Transcript Study.com ''. Study.com. Retrieved 2017 - 04 - 06. External links The European Membrane House, a non-profit international association created to continue the work of the network and parternships developed in NanoMemPro, an earlier EU - funded European network of membrane researchers. Short, non-scholarly WiseGeek article, `` What is a Semipermeable Membrane. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Semipermeable_membrane&oldid=808398907 '' Categories : Diffusion Filters Membrane biology Membrane technology Hidden categories : Articles needing additional references from July 2017 All articles needing additional references Articles needing expert attention from January 2016 All articles needing expert attention Chemistry articles needing expert attention Pharmacology articles needing expert attention Articles lacking reliable references from January 2016 All articles lacking reliable references All accuracy disputes Articles with disputed statements from January 2016 Articles needing additional references from January 2016 All articles with unsourced statements Articles with unsourced statements from January 2016 All pages needing factual verification Wikipedia articles needing factual verification from January 2016 Talk Contents About Wikipedia Bosanski Català Čeština ChiShona Dansk Deutsch Eesti Español Esperanto فارسی Français 한국어 Հայերեն हिन्दी Italiano עברית Kreyòl ayisyen Bahasa Melayu Nederlands 日本 語 Polski Русский کوردی Suomi Svenska ไทย 中文 Edit links This page was last edited on 2 November 2017, at 16 : 54. 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Question: the selective permeability of a cell membrane to different substances depends on
Answer: the pressure, concentration, and temperature of the molecules