tag:blogger.com,1999:blog-62885403772829418422023-11-16T02:59:30.961-08:00Passive and Active transportEscherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-6288540377282941842.post-91220777764745159972007-08-09T01:06:00.000-07:002007-08-21T04:09:28.897-07:00INSIGHTS<table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><tbody><tr height="100%" width="100%" unselectable="on"><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><p><strong><em><span style="font-family:georgia;font-size:130%;">KEANA'S INSIGHT</span></em></strong><br /><strong><em><span style="font-family:Georgia;font-size:130%;">Passive and Active transport is just easy to understand without the other biological term used by mam Fernandez. We choose this topic for our project, even if we have some difficulties in understanding the lesson, this project is also a big help for us to understand more about PASSIVE AND ACTIVE TRANSPORT..</span></em></strong><br /><strong><em><span style="font-family:Georgia;font-size:130%;"></span></em></strong><br /><strong><em><span style="font-family:Georgia;font-size:130%;">MAAYA'S INSIGHT</span></em></strong><br /><strong><em><span style="font-family:Georgia;font-size:130%;">for me active and passive are both very difficult to understand to understand. when prof. fernandez discuss it to us i really don't understand and when our leader decided that our project will be about passive and active i want to change the topic into an easy one but they continued it and now when the project was done i was so happy and i understand now some things about it when we researched for it. and i think i learn fro this project.</span></em></strong> </p><p><strong><em><span style="font-size:130%;">PAOLO'S INSIGHT</span></em></strong></p><p><strong><em><span style="font-size:130%;">I have learned that materials can go in and out the cell in the process of endocytosis. Endocytosis takes the material in by forming an infolding. Exocytosis is when waste materials move out the cell.</span></em></strong></p><p><strong><em><span style="font-family:georgia;font-size:130%;">Leifrance's Insight</span></em></strong></p><p><strong><em><span style="font-size:130%;">I've learned that not all the resources needed by the cell comes from their inside enviroment, they also need the resources outside like the oxgen, protien, they need it for their production.</span></em></strong></p><p><strong><em><span style="font-size:130%;">Dexter's Insight</span></em></strong></p><p><strong><em><span style="font-size:130%;">Mateials can go in and out of the cell by the different process like diffusion and osmosis have similarities but they also have differences like osmosis happens on water. Facilitated diffusion and active transport use a carrier or chanel proteien.</span></em></strong></p><p><strong><em><span style="font-family:georgia;font-size:130%;">Lyah's Insight</span></em></strong></p><p><strong><em><span style="font-size:130%;">I've learned about Passive and Active transport is that passive transport occurs when there is a difference in concentration between substnaces either side of the membranr of cellular tranport wherein substance move against the concentration gradient.</span></em></strong></p><p><strong><em><span style="font-size:130%;">Passive transport includes diffusion, and osmosis (hypotonic, isotonic, hypertonic).</span></em></strong></p><p><strong><em><span style="font-size:130%;">I've learned a lot. This helps me to give more information about the movement of molecules.</span></em></strong></p><p><strong></strong></p><p><br /></p></td></tr><tr unselectable="on" hb_tag="1"><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><div id="hotbar_promo"></div></td></tr></tbody></table>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-10921388706838289422007-08-09T01:05:00.001-07:002007-08-09T01:34:27.314-07:00CONCLUSION<table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><tbody><tr height="100%" width="100%" unselectable="on"><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><p><br /><span style="font-size:130%;"><strong><em>There are two types of transport across a cell's plasma membrane: active and passive. Any time energy is required for movement across the plasma membrane, active transport has occurred. When such energy does not need to be expended, passive transport is in operation. Passive transport can include either simple diffusion or facilitated diffusion. Simple diffusion is diffusion that does not require a protein channel. Facilitated diffusion is diffusion that requires a protein channel. In facilitated diffusion, transport proteins act as channels for hydrophilic substances that, due to their size and electrical charge, cannot diffuse through the plasma membrane.</em></strong></span></p><p><span style="font-size:130%;"><strong><em>In active transport, molecules again move through a transport protein, but now energy must be expended to move them against their concentration gradient. The cell's solution to moving solutes against their concentration gradients is pumps. Many kinds of pumps are in operation in active transport, but each is specific for one or perhaps two substances. The energy source for such transport is ATP (adenosine triphosphate).</em></strong></span></p></td></tr><tr hb_tag="1" unselectable="on"><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><div id="hotbar_promo"><span style="font-size:130%;"><strong><em></em></strong></span></div></td></tr></tbody></table>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com1tag:blogger.com,1999:blog-6288540377282941842.post-64255338820475732362007-08-05T01:13:00.000-07:002007-08-05T01:24:55.695-07:00EXOCYTOSIS<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYms4x-kLJNTvYOTQ19Ilnu45uZpiLUK3YQBSCINOHgzXG7r1OnxD0zFAcSbXZlBwbNVnGJVosV9ur0PnN0DVkNxVpjlewwPk2OuFC1lbJ_Yl15Gr1ln-YeH3cUAqI9dni4c2OrYVB-YE/s1600-h/Image152.gif"><img id="BLOGGER_PHOTO_ID_5095129486172688898" style="DISPLAY: block; MARGIN: 0px auto 10px; CURSOR: hand; TEXT-ALIGN: center" alt="" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYms4x-kLJNTvYOTQ19Ilnu45uZpiLUK3YQBSCINOHgzXG7r1OnxD0zFAcSbXZlBwbNVnGJVosV9ur0PnN0DVkNxVpjlewwPk2OuFC1lbJ_Yl15Gr1ln-YeH3cUAqI9dni4c2OrYVB-YE/s320/Image152.gif" border="0" /></a><br /><table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><br /><tbody><br /><tr height="100%" unselectable="on" width="100%"><br /><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><br /><div><span style="font-family:times new roman;font-size:130%;"><strong><em>EXOCYTOIS</em></strong></span></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">+ is the process by which a cell directs secretory vesicles to the <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane" target="_blank" rel="nofollow">cell membrane</a>. These membrane-bound vesicles contain soluble <a title="Proteins" href="http://en.wikipedia.org/wiki/Proteins" target="_blank" rel="nofollow">proteins</a> to be secreted to the extracellular environment, as well as <a title="Membrane proteins" href="http://en.wikipedia.org/wiki/Membrane_proteins" target="_blank" rel="nofollow">membrane proteins</a> and <a title="Lipids" href="http://en.wikipedia.org/wiki/Lipids" target="_blank" rel="nofollow">lipids</a> that are sent to become components of the cell membrane.</span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;"></span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">TYPES</span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">In multicellular organisms there are two types of exocytosis: 1) Ca2+ triggered non-constitutive and 2) non Ca2+ triggered constitutive. Exocytosis in neuronal chemical <a title="Synapses" href="http://en.wikipedia.org/wiki/Synapses" target="_blank" rel="nofollow">synapses</a> is Ca2+ triggered and serves interneuronal signalling. Constitutive exocytosis is performed by all cells and serves the release of components of the <a title="Extracellular matrix" href="http://en.wikipedia.org/wiki/Extracellular_matrix" target="_blank" rel="nofollow">extracellular matrix</a>, or just delivery of newly-synthesized membrane proteins that are incorporated in the <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane" target="_blank" rel="nofollow">plasma membrane</a> after the fusion of the transport <a title="Vesicle (biology)" href="http://en.wikipedia.org/wiki/Vesicle_(biology)" target="_blank" rel="nofollow">vesicle</a></span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;"></span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">FUNCTION</span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">Exocytosis is needed by cells for <a title="Secretion" href="http://en.wikipedia.org/wiki/Secretion" target="_blank" rel="nofollow">secretion</a> of <a title="Protein" href="http://en.wikipedia.org/wiki/Protein" target="_blank" rel="nofollow">proteins</a> like <a title="Enzyme" href="http://en.wikipedia.org/wiki/Enzyme" target="_blank" rel="nofollow">enzymes</a>, <a title="Peptide hormone" href="http://en.wikipedia.org/wiki/Peptide_hormone" target="_blank" rel="nofollow">peptide hormones</a> and <a title="Antibody" href="http://en.wikipedia.org/wiki/Antibody" target="_blank" rel="nofollow">antibodies</a> from cells, turnover of <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane" target="_blank" rel="nofollow">plasma membrane</a>, release of <a title="Neurotransmitter" href="http://en.wikipedia.org/wiki/Neurotransmitter" target="_blank" rel="nofollow">neurotransmitter</a> from presynaptic neurons, placement of integral membrane proteins, acrosome reaction during fertilization, <a title="Antigen" href="http://en.wikipedia.org/wiki/Antigen" target="_blank" rel="nofollow">antigen</a> presentation during the immune response and recycling of <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane" target="_blank" rel="nofollow">plasma membrane</a> bound receptors.<br />Exocytosis is important in cellular signaling. In neuronal communication both chemical and electrical information needs to be sent throughout the cell. Exocytosis sends and converts the electrical information into chemical information. Within the neural cells, the information is electrical. In the synapse, after exocytosis has occurred, the neurotransmitters are released, and the information is chemical. The release of the neurotransmitter can either be excitatory (causing activity from the target cell) or inhibitory (preventing activity by the target cell).</span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;"></span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">PROCESS</span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">Membrane-bound vesicles move to the cell surface where they fuse with the plasma membrane. This accomplishes three things:<br />It restores the normal amount of plasma membrane.<br />Any molecules dissolved in the fluid contents of these vesicles are discharged into the extracellular fluid - this is called secretion.Example: the various components of the <a href="http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/ECM.html" target="_blank" rel="nofollow">extracellular matrix</a> are secreted by exocytosis.<br />Any <a href="http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellMembranes.html#Integral_TransmembraneProteins" target="_blank" rel="nofollow">integral membrane proteins</a> exposed to the interior surface of the vesicles will now be displayed at the cell surface because the vesicles turn inside out as they fuse with the plasma membrane. Thus exocytosis does not simply replace plasma membrane but ensures that the plasma membrane will display its characteristic cell-surface proteins. </span></em></strong></div><br /><div><strong><em><span style="font-family:Times New Roman;font-size:130%;">Exocytic vesicles are created from several sources:<br />Some are simply <a href="http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Endocytosis.html" target="_blank" rel="nofollow">endosomes</a> traversing the cell.<br />Others are pinched off from endosomes before they fuse with lysosomes.<br />Others bud off from the endoplasmic reticulum and Golgi apparatus taking their products to the surface of the cell.<br />The exocytosis of <a href="http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/L/Lysosomes.html" target="_blank" rel="nofollow">lysosomes</a> supplies the membrane needed to repair wounds in the plasma membrane. </span></em></strong></div></td></tr><br /><tr unselectable="on" hb_tag="1"><br /><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><br /><div id="hotbar_promo"></div></td></tr></tbody></table><br /><p></p><br /><p></p>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-50985825228163822382007-08-05T01:02:00.000-07:002007-08-05T01:12:32.286-07:00ENDOCYTOSIS<a href="http://35.9.122.184/images/08-MembraneStructureAndFunction/08-19-EndocytosisArt-L.jpg"><img style="DISPLAY: block; MARGIN: 0px auto 10px; WIDTH: 320px; CURSOR: hand; TEXT-ALIGN: center" alt="" src="http://35.9.122.184/images/08-MembraneStructureAndFunction/08-19-EndocytosisArt-L.jpg" border="0" /></a><br /><table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><br /><tbody><tr height="100%" unselectable="on" width="100%"><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><br /><div><span style="font-size:180%;"><strong><em>ENDOCYTOSIS<br />>>> is a process whereby <a title="Cell (biology)" href="http://en.wikipedia.org/wiki/Cell_(biology)" target="_blank" rel="nofollow">cells</a> absorb material (<a title="Molecules" href="http://en.wikipedia.org/wiki/Molecules" target="_blank" rel="nofollow">molecules</a> such as proteins) from the outside by engulfing it with their <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane" target="_blank" rel="nofollow">cell membrane</a>. It is used by all cells of the <a title="Body" href="http://en.wikipedia.org/wiki/Body" target="_blank" rel="nofollow">body</a> because most substances important to them are <a title="Polar" href="http://en.wikipedia.org/wiki/Polar" target="_blank" rel="nofollow">polar</a> and consist of big molecules, and thus cannot pass through the <a title="Hydrophobic" href="http://en.wikipedia.org/wiki/Hydrophobic" target="_blank" rel="nofollow">hydrophobic</a> <a title="Plasma membrane" href="http://en.wikipedia.org/wiki/Plasma_membrane" target="_blank" rel="nofollow">plasma membrane</a>. The function of endocytosis is the opposite of <a title="Exocytosis" href="http://en.wikipedia.org/wiki/Exocytosis" target="_blank" rel="nofollow">exocytosis</a></em></strong></span></div><br /><div><strong><em><span style="font-size:180%;"></span></em></strong></div><br /><div><strong><em><span style="font-size:180%;">TYPES OF ENDOCYTOSIS<br />1. Phagocytosis- (literally, cell-eating) the process by which cells ingest large objects, such as cells which have undergone <a title="Apoptosis" href="http://en.wikipedia.org/wiki/Apoptosis" target="_blank" rel="nofollow">apoptosis</a>, <a title="Bacteria" href="http://en.wikipedia.org/wiki/Bacteria" target="_blank" rel="nofollow">bacteria</a>, or <a title="Virus" href="http://en.wikipedia.org/wiki/Virus" target="_blank" rel="nofollow">viruses</a>. The membrane folds around the object, and the object is sealed off into a large <a title="Vacuole" href="http://en.wikipedia.org/wiki/Vacuole" target="_blank" rel="nofollow">vacuole</a> known as a <a title="Phagosome" href="http://en.wikipedia.org/wiki/Phagosome" target="_blank" rel="nofollow">phagosome</a></span></em></strong></div><br /><div><strong><em><span style="font-size:180%;">2. Pinocytosis- (literally, cell-drinking) is a synonym for endocytosis. This process is concerned with the uptake of <a title="Solutes" href="http://en.wikipedia.org/wiki/Solutes" target="_blank" rel="nofollow">solutes</a> and single molecules such as <a title="Proteins" href="http://en.wikipedia.org/wiki/Proteins" target="_blank" rel="nofollow">proteins</a>. </span></em></strong></div><br /><div><strong><em><span style="font-size:180%;">3. Receptor- mediated endocytosis is a more specific active event where the cytoplasm membrane folds inward to form coated pits. These inward budding vesicles bud to form cytoplasmic vesicles. </span></em></strong></div></td></tr><br /><tr unselectable="on" hb_tag="1"><br /><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><br /><div id="hotbar_promo"></div></td></tr></tbody></table>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-87868283416766182712007-08-05T00:54:00.000-07:002007-08-05T01:01:48.793-07:00ACTIVE TRANSPORT<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8ThTdpDhTLVYQNTFhqIKsAjKWi_egHt3Y03aHkbWhFwyDV6ccquOzgAO2RTJ8H0u_F-BFnpO1LEBY94IYP-SayUgBHnS2zbtfTKGnrVMZuCyl7K4aYYydZGbFlb6F_te2sFrLqhZM_mI/s1600-h/active_transport.jpg"><img id="BLOGGER_PHOTO_ID_5095122828973380082" style="DISPLAY: block; MARGIN: 0px auto 10px; CURSOR: hand; TEXT-ALIGN: center" alt="" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8ThTdpDhTLVYQNTFhqIKsAjKWi_egHt3Y03aHkbWhFwyDV6ccquOzgAO2RTJ8H0u_F-BFnpO1LEBY94IYP-SayUgBHnS2zbtfTKGnrVMZuCyl7K4aYYydZGbFlb6F_te2sFrLqhZM_mI/s320/active_transport.jpg" border="0" /></a><br /><strong><em></em></strong><br /><table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><tbody><br /><tr height="100%" unselectable="on" width="100%"><br /><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><br /><div><span style="font-family:courier new;font-size:180%;"><strong><em>ACTIVE TRANSPORT</em></strong></span></div><br /><div><strong><em><span style="font-family:Courier New;font-size:180%;"> +(sometimes called active uptake) is the <a title="Mediated transport" href="http://en.wikipedia.org/wiki/Mediated_transport" target="_blank" rel="nofollow">mediated transport</a> of <a title="Biochemistry" href="http://en.wikipedia.org/wiki/Biochemistry" target="_blank" rel="nofollow">biochemicals</a>, and other <a title="Atom" href="http://en.wikipedia.org/wiki/Atom" target="_blank" rel="nofollow">atomic</a>/<a title="Molecule" href="http://en.wikipedia.org/wiki/Molecule" target="_blank" rel="nofollow">molecular</a> substances, across <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane" target="_blank" rel="nofollow">membranes</a>. Unlike <a title="Passive transport" href="http://en.wikipedia.org/wiki/Passive_transport" target="_blank" rel="nofollow">passive transport</a>, this process requires the expenditure of cellular <a title="Energy" href="http://en.wikipedia.org/wiki/Energy" target="_blank" rel="nofollow">energy</a> to move molecules "uphill" against a gradient.</span></em></strong></div><div><strong><em><span style="font-family:Courier New;font-size:180%;"></span></em></strong> </div><div><strong><em><span style="font-family:Courier New;font-size:180%;"> +involves the use of proteins that don't just passively facilitate the transport of substances across the cell membrane, but require the use of cellular energy(usually ATP) to actively pump substances into or out of the cell. The animation represents the action of a sodium-potassium pump found in the cell membrane of neurons. This protein pumps sodium ions(red squares) from the inside to the outside of the neuron and pumps potassium ions(green squares)in the opposite direction. Notice the cell must use ATP(purple) for this process. As the sodium fits onto a site on the protein, a phosphate is transferred to the protein providing energy to kick the sodium ion to the outside and the potassium ion to the inside. This process sets up a high concentration of sodium ions outside the cell and a high concentration of potassim ions inside the cell. This concentration difference across the membrane is important for the generation of thenerve impulses by which neurons transmit information from on end of the neuron to the other. So even if you're zoned out in front of the tube your neurons are actively working to maintain this concentration difference...just in case they nave to send any information. <br />Active transport is used to: <br />1. Generate charge gradients. For example in the mitochondrion, hydrogen ion pumps pump hydrogen ions into the intermembrane space of the organelle as part of making ATP. <br />2. Concentrate ions, minerals and nutrients inside the cell that are in low concentration outside. <br />3. Keep unwanted ions or other molecules out of the cell that are able to diffuse through the cell membrane. <br />In all these cases the key is that active transport uses energy to send substances against the direction they would travel by simple diffusion: that is from a region of low concentration to a region of high concentration</span></em></strong></div><div><strong><em><span style="font-family:Courier New;font-size:180%;"></span></em></strong> </div><div><strong><em><span style="font-family:Courier New;font-size:180%;">~In this form of transport, molecules move against either an electrical or concentration gradient (collectively termed an <a title="Electrochemical potential" href="http://en.wikipedia.org/wiki/Electrochemical_potential" target="_blank" rel="nofollow">electrochemical gradient</a>).<br />The active transport of small molecules or ions across a cell membrane is generally carried out by transport proteins that are found in the membrane.<br />Larger molecules such as <a title="Starch" href="http://en.wikipedia.org/wiki/Starch" target="_blank" rel="nofollow">starch</a> can also be actively transported across the cell membrane by processes known as <a title="Endocytosis" href="http://en.wikipedia.org/wiki/Endocytosis" target="_blank" rel="nofollow">endocytosis</a> and <a title="Exocytosis" href="http://en.wikipedia.org/wiki/Exocytosis" target="_blank" rel="nofollow">exocytosis</a>.<br />Particles that are moved through a membrane from a region of low concentration to high is known as active transport. </span></em></strong></div><div><strong><em><span style="font-family:Courier New;font-size:180%;"></span></em></strong> </div><div><strong><em><span style="font-family:Courier New;font-size:180%;">TYPES</span></em></strong></div><div><strong><em><span style="font-family:Courier New;font-size:180%;"> In primary transport, energy from hydrolysis of <a title="Adenosine triphosphate" href="http://en.wikipedia.org/wiki/Adenosine_triphosphate" target="_blank" rel="nofollow">ATP</a> is directly coupled to the movement of a specific substance across a membrane independent of any other species.<a title="" href="http://en.wikipedia.org/wiki/Active_transport#_note-0" target="_blank" rel="nofollow">[1]</a><br />In secondary active transport, the required energy is derived from energy stored in the form of concentration differences in a second solute. Typically, the concentration gradient of the second solute was created by primary active transport, and the diffusion of the second solute across the membrane drives secondary active transport of the first solute.<a title="" href="http://en.wikipedia.org/wiki/Active_transport#_note-1" target="_blank" rel="nofollow">[2]</a> </span></em></strong></div><div><strong><em><span style="font-family:Courier New;font-size:180%;"></span></em></strong> </div><div><strong><em><span style="font-family:Courier New;font-size:180%;"></span></em></strong> </div></td></tr><br /><tr unselectable="on" hb_tag="1"><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><br /><div id="hotbar_promo"></div></td></tr></tbody></table>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-47353902833291462622007-08-05T00:46:00.000-07:002007-08-05T00:51:30.589-07:00FACILITATED DIFFUSION<a href="http://www.mhhe.com/biosci/genbio/enger/student/olc/art_quizzes/genbiomedia/0086.jpg"><img style="DISPLAY: block; MARGIN: 0px auto 10px; WIDTH: 320px; CURSOR: hand; TEXT-ALIGN: center" alt="" src="http://www.mhhe.com/biosci/genbio/enger/student/olc/art_quizzes/genbiomedia/0086.jpg" border="0" /></a><br /><table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><tbody><tr height="100%" unselectable="on" width="100%"><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><br /><strong><em><span style="font-size:180%;">FACILITATED DIFFUSION<br /></span><span style="font-size:130%;">~Facilitated diffusion (or facilitated transport) is a process of <a title="Diffusion" href="http://en.wikipedia.org/wiki/Diffusion">diffusion</a>, a form of <a title="Passive transport" href="http://en.wikipedia.org/wiki/Passive_transport">passive transport</a>, where <a title="Molecule" href="http://en.wikipedia.org/wiki/Molecule">molecules</a> diffuse across <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane">membranes</a>, with the assistance of <a title="Transport protein" href="http://en.wikipedia.org/wiki/Transport_protein">transport proteins</a>.<br />Charged <a title="Ions" href="http://en.wikipedia.org/wiki/Ions">ions</a> dissolve in water and diffuse through water channel <a title="Proteins" href="http://en.wikipedia.org/wiki/Proteins">proteins</a>. These ion channels are gated so they can open and close, thus regulating the ion flow. Larger molecules diffuse through carrier proteins that change shape as the <a title="Molecules" href="http://en.wikipedia.org/wiki/Molecules">molecules</a> are carried through, for example <a title="Glucose" href="http://en.wikipedia.org/wiki/Glucose">glucose</a> and <a title="Amino acids" href="http://en.wikipedia.org/wiki/Amino_acids">amino acids</a>.<br />Small uncharged molecules can easily diffuse across cell membranes. However, due to the <a title="Hydrophobe" href="http://en.wikipedia.org/wiki/Hydrophobe">hydrophobic</a> nature of the <a title="Lipid" href="http://en.wikipedia.org/wiki/Lipid">lipids</a> that make up cell membranes, water-soluble molecules and ions cannot do so; instead, they are helped across by transport proteins. The transport protein involved is intrinsic(transmembranal), that is, it completely spans the membrane. It also has a binding site for the specific molecule such as <a title="Glucose" href="http://en.wikipedia.org/wiki/Glucose">glucose</a>, or ion to be transported. After binding to the molecule, the protein changes shape and carries the molecule across the membrane, where it is released. The protein then returns to its original shape, to wait for more molecules to transport.<br />In contrast to <a title="Active transport" href="http://en.wikipedia.org/wiki/Active_transport">active transport</a>, facilitated diffusion does not require metabolic energy (<a title="Adenosine triphosphate" href="http://en.wikipedia.org/wiki/Adenosine_triphosphate">ATP</a>) and carries molecules or ions down a concentration gradient.<br />Facilitated diffusion can take place in pores and gated channels. Pores never close, but gated channels open and close in response to stimuli.<br />The transport proteins participating in facilitated diffusion resemble <a title="Enzymes" href="http://en.wikipedia.org/wiki/Enzymes">enzymes</a>. Just as enzymes are substrate specific and only catalyse certain substrates, transport proteins are solute specific and only transport certain solutes. Transport proteins also have a limit of how many solutes they can transport. Finally, molecules can inhibit the protein in a way similar to <a title="Competitive inhibition" href="http://en.wikipedia.org/wiki/Competitive_inhibition">competitive inhibition</a> in enzymes.<br />As an example of facilitated diffusion, <a title="Glucose" href="http://en.wikipedia.org/wiki/Glucose">glucose</a> molecules <a title="Diffusion" href="http://en.wikipedia.org/wiki/Diffusion">diffuse</a> by <a title="Simple diffusion" href="http://en.wikipedia.org/wiki/Simple_diffusion">simple diffusion</a> only very slowly across a <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane">cell membrane</a> since glucose is not readily soluble in the <a title="Phospholipid bilayer" href="http://en.wikipedia.org/wiki/Phospholipid_bilayer">phospholipid bilayer</a>. However, glucose diffuses very quickly across a cell membrane by facilitated diffusion because the <a title="Carrier proteins" href="http://en.wikipedia.org/wiki/Carrier_proteins">carrier proteins</a> help the glucose molecule cross into the cell. Specific examples: <a title="GLUT1" href="http://en.wikipedia.org/wiki/GLUT1">GLUT1</a> in erythrocytes, a passive transporter involved in importing glucose molecules and <a title="GLUT2" href="http://en.wikipedia.org/wiki/GLUT2">GLUT2</a> in liver cells, involved in importing glucose molecules.</span></em></strong></td></tr><tr unselectable="on" hb_tag="1"><br /><br /><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><br /><br /><div id="hotbar_promo"></div></td></tr></tbody></table>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-36585381452275613212007-08-05T00:23:00.000-07:002007-08-05T00:46:01.352-07:00OSMOSIS<table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><tbody><tr height="100%" unselectable="on" width="100%"><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><strong><em><span style="font-family:trebuchet ms;font-size:180%;">OSMOSIS</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"> => transfer of a liquid solvent through a semipermeable membrane that does not allow dissolved solids (solutes) to pass. Osmosis refers only to transfer of solvent; transfer of solute is called <a href="http://education.yahoo.com/reference/encyclopedia/entry/dialysis;_ylt=AqO_aGtxk_jcin0hoUNQw_ZTt8wF" target="_blank" rel="nofollow">dialysis</a>. In either case the direction of transfer is from the area of higher concentration of the material transferred to the area of lower concentration. This spontaneous migration of a material from a region of higher concentration to a region of lower concentration is called <a href="http://education.yahoo.com/reference/encyclopedia/entry/diffusio;_ylt=Alu_3lEbmPrrgwUs1JFaEBhTt8wF" target="_blank" rel="nofollow">diffusion</a><br /> </span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;">PRINCIPLES OF OSMOSIS</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"> =>Osmosis will occur if a vessel is separated into two compartments by a semipermeable membrane, both compartments are filled to the same level with a solvent, and solute is added to one side. The level of the liquid on the side containing the solute will rise as the solvent flows from the side of its higher concentration to the side of lower concentration. If an external pressure is exerted on the side containing the solute, the transfer of solvent can be stopped and even reversed (reverse osmosis). Two solutions separated by a semipermeable membrane are said to be isotonic if no osmosis occurs. If osmosis occurs, transfer of solvent is from the hypotonic solution to the hypertonic solution, which has the higher osmotic pressure.<br />The minimum pressure necessary to stop solvent transfer is called the osmotic pressure. Since the osmotic pressure is related to the concentration of solute particles, there is a mathematical relationship between osmotic pressure, freezing-point depression, and boiling-point elevation. Properties such as osmotic pressure, freezing point, and boiling point, which depend on the number of particles present rather than on their size or chemical nature, are called colligative properties. For dilute solutions the mathematical relationship between the osmotic pressure, temperature, and concentration of solute is much like the relation between pressure, temperature, and volume in an ideal gas (see <a href="http://education.yahoo.com/reference/encyclopedia/entry/gaslaws;_ylt=AuyEBsSyjyN2W1oT5SIYYBRTt8wF" target="_blank" rel="nofollow">gas laws</a>). A number of theories explaining osmotic pressure by analogy to gases have been devised, but most have been discarded in favor of thermodynamic interpretations using such concepts as the entropy of dilution. </span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"></span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;">BIOLOGICAL IMPORTANCE OF OSMOSIS</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"> =>Osmosis and dialysis are of prime importance in living organisms, where they influence the distribution of nutrients and the release of metabolic waste products. Living cells of both plants and animals are enclosed by a semipermeable membrane called the cell membrane, which regulates the flow of liquids and of dissolved solids and gases into and out of the cell. The membrane forms a selective barrier between the cell and its environment; not all substances can pass through the membrane with equal facility. Without this selectivity, the substances necessary to the life of the cell would diffuse uniformly into the cell's surroundings, and toxic materials from the surroundings would enter the cell.<br />If blood cells (or other cells) are placed in contact with an isotonic solution, they will neither shrink nor swell. If the solution is hypertonic, the cells will lose water and shrink (plasmolyze). If the solution is hypotonic (or if pure solvent is used) the cells will swell; the osmotic pressure that is developed may even be great enough to rupture the cell membrane. Saltwater from the ocean is hypertonic to the cells of the human body; the drinking of ocean water dehydrates body tissues instead of quenching thirst.<br />In plants osmosis is at least partially responsible for the absorption of soil water by root hairs and for the elevation of the liquid to the leaves of the plant. However, plants wilt when watered with saltwater or treated with too much fertilizer, since the soil around their roots then becomes hypertonic.</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"></span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;">HYPERTONIC SOLUITION</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"> =>contain a high concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrivel. </span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"></span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;">HYPOTONIC SOLUTION</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"> =>contain a low concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the cell to swell and possibly explode</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"></span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;">ISOTONIC SOLUTION</span></em></strong><br /><strong><em><span style="font-family:Trebuchet MS;font-size:180%;"> =>contain the same concentration of solute as an another solution (e.g. the cell's cytoplasm). When a cell is placed in an isotonic solution, the water diffuses into and out of the cell at the same rate. The fluid that surrounds the body cells is isotonic. </span></em></strong><br /> <br /><br /><br /></td></tr><tr unselectable="on" hb_tag="1"><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><div id="hotbar_promo"></div></td></tr></tbody></table>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-63768824759775583892007-08-05T00:11:00.000-07:002007-08-05T00:20:40.544-07:00DIFFUSION<a href="http://www.indiana.edu/~phys215/lecture/lecnotes/lecgraphics/diffusion2.gif"><img style="DISPLAY: block; MARGIN: 0px auto 10px; WIDTH: 320px; CURSOR: hand; TEXT-ALIGN: center" alt="" src="http://www.indiana.edu/~phys215/lecture/lecnotes/lecgraphics/diffusion2.gif" border="0" /></a><br /><div><br /><br /><table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><br /><br /><tbody><br /><br /><tr height="100%" unselectable="on" width="100%"><br /><br /><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><br /><br /><div><span style="font-family:lucida grande;font-size:180%;"><strong><em>DIFFUSION</em></strong></span></div><br /><br /><div><strong><em><span style="font-size:180%;">~net movement of material from an area of high concentration of that material to an area with lower concentration. The difference of concentration between the two areas is often termed as the concentration gradient, and diffusion will continue until this gradient has been eliminated. Since diffusion moves materials from an area of higher concentration to the lower, it is described as moving solutes "down the concentration gradient" (compared with <a title="Active transport" href="http://en.wikipedia.org/wiki/Active_transport">active transport</a>, which often moves material from area of low concentration to area of higher concentration, and therefore referred to as moving the material "against the concentration gradient").</span></em></strong></div></td></tr><br /><br /><tr unselectable="on" hb_tag="1"><br /><br /><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><br /><br /><div id="hotbar_promo"></div></td></tr></tbody></table></div>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-34715573599093871432007-08-04T23:57:00.000-07:002007-08-05T00:08:55.782-07:00Passive Transport<table id="HB_Mail_Container" height="100%" cellspacing="0" cellpadding="0" width="100%" border="0" unselectable="on"><tbody><tr height="100%" unselectable="on" width="100%"><td id="HB_Focus_Element" valign="top" width="100%" background="" height="250" unselectable="off"><span style="font-size:180%;"><strong><em>PASSIVE TRANSPORT </em></strong></span><br /><strong><em><span style="font-size:180%;"> </span><span style="font-size:130%;">>>>occurs when there is a difference in concentration between substanceson either side of the cell membrane. Molecules move from regions of higher concentration to lower concentration.</span></em></strong><br /><strong><em><span style="font-size:130%;"> >>>Passive transport is a means of <a title="Motion (physics)" href="http://en.wikipedia.org/wiki/Motion_%28physics%29">moving</a> <a title="Biochemistry" href="http://en.wikipedia.org/wiki/Biochemistry">biochemicals</a>, and other <a title="Atom" href="http://en.wikipedia.org/wiki/Atom">atomic</a> or <a title="Molecule" href="http://en.wikipedia.org/wiki/Molecule">molecular</a> substances, across <a title="Cell membrane" href="http://en.wikipedia.org/wiki/Cell_membrane">membranes</a>. Unlike <a title="Active transport" href="http://en.wikipedia.org/wiki/Active_transport">active transport</a>, this process does not involve <a title="Chemistry" href="http://en.wikipedia.org/wiki/Chemistry">chemical</a> <a title="Energy" href="http://en.wikipedia.org/wiki/Energy">energy</a>. Passive transport is dependent on the permeability of the cell membrane, which, in turn, is dependent on the organization and characteristics of the membrane lipids and proteins.</span></em></strong><br /><strong><em><span style="font-size:130%;"></span></em></strong><br /><strong><em><span style="font-size:130%;">CONCENTRATION GRADIENT</span></em></strong><br /><strong><em><span style="font-size:130%;"> >>> the concentration difference that determines molecule movement in either direction.</span></em></strong><br /><strong><em><span style="font-size:130%;"></span></em></strong><br /><strong><em><span style="font-size:130%;">THE FOUR MAIN KIND OF PASSIVE TRANSPORT</span></em></strong><br /><strong><em><span style="font-size:130%;">~DIFFUSION</span></em></strong><br /><strong><em><span style="font-size:130%;">~OSMOSIS</span></em></strong><br /><strong><em><span style="font-size:130%;">~FACILITATED DIFFUSION</span></em></strong><br /></td></tr><tr unselectable="on" hb_tag="1"><td style="FONT-SIZE: 1pt" height="1" unselectable="on"><div id="hotbar_promo"></div></td></tr></tbody></table>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0tag:blogger.com,1999:blog-6288540377282941842.post-87326651745856257942007-08-04T23:54:00.000-07:002007-08-09T01:35:55.663-07:00INTRODUCTION<p> </p><p><span style="font-family:trebuchet ms;"><strong><em><span style="font-size:130%;">Molecules can be transported across the plasma membrane via passive or active transport. Active transport is characterized as requiring energy in the form of ATP, while passive transport does not require energy. During active transport pumps are often used to assist in moving a molecule against a concentration gradient</span>.</em></strong></span></p><p><br /><span style="font-family:trebuchet ms;font-size:130%;"><strong><em>Compare and contrast active vs. passive transport.</em></strong></span></p><p><br /><span style="font-family:trebuchet ms;font-size:130%;"><strong><em>Passive transport, shown below, is the diffusion of particles through the proteins. The particles move from an area of high concentration to an area of low concentration. The cell does not need to use any energy to make this happen.</em></strong></span></p><p><br /><span style="font-family:trebuchet ms;font-size:130%;"><strong><em>Active transport, shown below, is the movement of particles through proteins against the normal direction of diffusion. In other words, particles are moved from an area of low concentration to an area of high concentration. The cell must use energy to make this happen. This energy comes from the molecule ATP, which stores energy in a form that cells can use.</em></strong></span></p><p><strong><em><span style="font-family:trebuchet ms;font-size:130%;"></span></em></strong></p><p><br /> </p><p></p>Escherichia Colihttp://www.blogger.com/profile/14321046459530462011noreply@blogger.com0