Hi, I have 7 physiological systems questions that I need desperate help with. I have attached the document containing the 7 questions thank you. If i'm pleases with the answers I also have another 13 potential questions. Please include all working out for the question.;Attached is also the notes for the experiment it is based on.;Attachments Preview;Biosensors practical notes updated version.docx Download Attachment;BioNanotechnology Practical: Ion Channels in Membranes.;Membrane Conduction and Ion Channels;Key Learning Objectives;1. Bilayer lipid membranes (BLM) are the major constituent of cell membranes.;2. BLMs block the passage of ions such as Na+, K+, Cl- and Ca++.;3. Ion channels penetrate cell membranes permitting the passage of ions across the membrane.;4. A convenient tool for studying the ion transport properties is a tethered membrane that is more;stable and easier to study than many other model systems.;5.;Gramicidin is bacterial polypeptide and is an example of an ion channel. In this practical class;you will be asked to fabricate a tethered membrane, insert gramicidin, and measure its;conductance.;6. You will be instructed to form a tethered membrane and to include in it the ion channel;Gramicidin.;7. You will need to measure the conductivity of Gramicidin in membrane and determine he;membrane thickness.;SDx tethered membranes March 2014.;BioNanotechnology Practical: Ion Channels in Membranes.;Background;Cell Membranes;Cell membrane properties control the behaviour of all plants, bacteria and animals. Cell membranes consist;of self-assembled supramolecular structures formed by amphiphiles, or compounds that have polar segments;that strongly attract water and non-polar segments that do not. This results in the non-polar segments being;excluded from the aqueous phase and assembling into bimolecular sheets which eventually form closed;spheres which are the precursors of biological cells. The amphiphiles we are interested in here are known as;lipids and the cell-like structures they form when dispersed in water are known as liposomes. Liposomes can;be 10 nm to hundreds of micrometres in diameter but all have walls that are approximately 4 nm thick, and;are nearly impermeable to ions such as Na+, K+ and Cl-. The 4 nm thick lipid bilayer, that forms the wall of a;liposome is similar to that found in all cell membranes, whether they are from bacteria, plants or animals.;Alterations in membrane ionic permeability are the basis of;Signalling between neurones in the brain, and between neurones in the sympathetic and;autonomic nervous systems.;The senses of sight, sound, taste touch and smell in animals, and related functions in plants;and bacteria.;Mitochondrial metabolism and bioenergetics.;Cell membrane biochemistry is a core discipline within medical research and a core interest of the;Pharmaceutical Industry when searching for drug targets to address a wide range of medical conditions.;Membrane research is a significant component of a current major international research effort focussed on;replacement antibiotics for penicillin which is becoming increasingly ineffective against methicillin resistant;bacterial strains of Staphylococcus Aureus. Compounds that interact with membranes are also important in;understanding the effects of many types of venom, toxins, and some chemical warfare agents..;Tethered membranes;Traditional techniques used to study transmembrane ion transport require the use very small liposomes or;single cells pieced using fragile microelectrodes. Tethered membranes provide a stable planar phospholipid;bilayer over a relatively large surface area (2-3 mm2) that is a convenient alternative tool to study ion;transport in membrane bound ion channels. The tethering of the membrane is achieved using sulphur;chemistry to gold (gold is not totally unreactive and possesses a chemistry with sulphur). Molecular tethers;are thus molecules that possess a sulphur group, polar linkers and a hydrophobic segment that embeds in the;lipid bilayer. The polar linkers allow the existence of an aqueous layer, between the gold electrode and the;membrane. The assembly of a tethered membrane is shown below.;SDx tethered membranes March 2014.;BioNanotechnology Practical: Ion Channels in Membranes.;(a) Ethanol solutions containing 0.4mM;disulphides are exposed to pure fresh gold;for 30 minutes. The molecules collide with;the gold and sulphur-gold bonds form;causing the self assembly of a lipid-spacer;monolayer. In todays practical class 10%;of the molecules are hydrophobic lipidic;anchor groups, and ninety percent are;hydrophilic spacers. This ratio can be;reduced to below 1% tether molecules or;up to 100% tether molecules. The motive;for reducing the fraction of tethers is to;provide more space to incorporate large;channels or to increase the number of;tethers to fabricate a more stable device.;(b) Following the adsorption of the self;assembled monolayer at the gold surface a;further 8ul of 3mM free lipid in ethanol is;allowed to assemble at the surface and then;rinsed with buffer.;(c) Rinsing with buffer causes the mix of;tethered and free lipids to form into a;tethered bilayer, 4nm thick on a 3nm;hydrophilic cushion. The hydrophilic;cushion mimics the inside of a cell and the;lipid bilayer mimics a cell membrane.;Ion Channels;SDx tethered membranes March 2014.;BioNanotechnology Practical: Ion Channels in Membranes.;Ion channels are molecules that create hydrophilic pathways across lipid bilayer membranes permiting ions;to cross otherwise impermeable membranes. Common bacteria such as Pneumonia, Diphtheria, Golden;Staphylococcus and Anthrax are pathogenic because the toxins they produce are ion channels that puncture;the cells of target organisms and collapse their transmembrane potentials.;Gramicidin (gA): Another ion channel, found in the soil bacteria, B. brevis is gramicidin A (See Figure;Below). Being much smaller, with molecular weight of 1882 Da, two molecules end-to-end are required to;span the lipid bilayer. Gramicidin is ion selective and is only conducive to monovalent cations (especially;Na+).;The bacterial ion channel gramicidin (gA). Monomers in the inner and outer leaflets of the bilayer;membrane need to align to form a continuous channel to permit ions to cross the membrane.;(a) Schematic figure of gramicidin A in a tethered membrane. An excitation potential of 20mV a.c. is applied;and the current due to ions being driven back and forth across the membrane is measured.;(b) More detail of gramcidin A showing two gramicidin monmers aligning and forming a conductive dimer.;Beneath the image of the dimer is an end view showing the pore through the centre of gramicidin through;which ions pass.;SDx tethered membranes March 2014.;BioNanotechnology Practical: Ion Channels in Membranes.;Membrane Preparation kit;A six-channel electrode is provided in this practical class that is to be assembled into a flow cell cartridge;(Fig 1A and 2A below). The assembled cartridge plugs into a conductance reader (Fig 2B below) [SDx;tethaPod ], that reads both the membrane conductance and capacitance. A cartridge preparation kit is;supplied by which consists of;individually packaged electrodes pre-coated with tethering chemistry (Fig. 3A below);a flow cell cartridge top containing the gold counter electrode (Fig.2A and 3B below);an alignment jig for use when attaching the electrode to the flow-cell cartridge (Fig. 1A and 3C;below);a silicon rubber pressure pad used when attaching the electrode to the flow cell cartridge (Fig. 3D;below);an aluminium pressure plate used when attaching the electrode to the flow cell cartridge (Fig. 3E;below);a pressure clamp is used when attaching the electrode to the flow cell cartridge (Fig. 1B below);FIGURE 1;FIGURE 2;FIGURE 3;SDx tethered membranes March 2014.;BioNanotechnology Practical: Ion Channels in Membranes.;In addition to the supplied membrane preparation kit you will need;(i) Pair of scissors to open the slide pack;(ii) A 10ul and 100ul pipette and tips to deliver the phospholipid (8l) and rinse with buffer(100l);(iii) Tweezers to remove the slide from the sealed pack.;(iv) Waste bin to collect used
physiological systems questions
This question was answered on: Dec 18, 2020
Buy this answer for only: $18.50
This attachment is locked
We have a ready expert answer for this paper which you can use for in-depth understanding, research editing or paraphrasing. You can buy it or order for a fresh, original and plagiarism-free copy (Deadline assured. Flexible pricing. TurnItIn Report provided)
Pay using PayPal (No PayPal account Required) or your credit card . All your purchases are securely protected by .
About this QuestionSTATUS
Dec 18, 2020EXPERT
GET INSTANT HELP/h4>
We have top-notch tutors who can do your essay/homework for you at a reasonable cost and then you can simply use that essay as a template to build your own arguments.
You can also use these solutions:
- As a reference for in-depth understanding of the subject.
- As a source of ideas / reasoning for your own research (if properly referenced)
- For editing and paraphrasing (check your institution's definition of plagiarism and recommended paraphrase).
NEW ASSIGNMENT HELP?
Order New Solution. Quick Turnaround
Click on the button below in order to Order for a New, Original and High-Quality Essay Solutions. New orders are original solutions and precise to your writing instruction requirements. Place a New Order using the button below.
WE GUARANTEE, THAT YOUR PAPER WILL BE WRITTEN FROM SCRATCH AND WITHIN YOUR SET DEADLINE.