The Effect of Temperature on the Permeability of Cell Membranes free essay sample

The effect of temperature on the permeability of cell membranes Introduction For my coursework, I intend to assess how temperature affects the plasma membrane of a cell. For this I will use the cell of a beetroot. Background What is a cell membrane? The cell membrane, also called the plasma membrane is a semipermeable lipid bilayer which is the surface of all cells that surrounds the cytoplasm. The membrane is called a bilayer as it has a double layer of phospholipids. Within the cell membrane there are many biological molecules, proteins and lipids, which are involved in cellular processes, and also serves as the attachment point for both the intracellular cytoskeleton and, if present, the cell wall. It is selectively permeable and chooses what molecules enter and leaves the cell and also maintains the cells potential. This following picture is a diagram of the fluid mosaic with all the different molecules labeled: Phospholipids – Phospholipids are a type of lipids which are key parts of all biological molecules, along with glycolipids, carbohydrates and proteins. We will write a custom essay sample on The Effect of Temperature on the Permeability of Cell Membranes or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The circular head of the phospholipid is the phosphate component. This is hydrophilic (Water Liking) therefore faces the aqueous part that surrounds the membrane. The tail of the phospholipid is the fatty acid component. This is the opposite of the phosphate as it is hydrophobic (Dislikes Water) therefore the tails point inwards towards each other as it is a bilayer forming a non-polar interior. Cholesterol- Cholesterols are the lipids found in the membranes of all tissues. The name cholesterol comes from the Greek words chole (Bile) and stereos (solid). The phospholipid molecule is like the cholesterol molecule in the way that the cholesterol also has hydrophilic (Water Liking) heads and hydrophobic (Dislikes Water) tails, therefore they are able to fit between the phospholipid molecules. The cholesterol molecule helps keeps the fluidity of the cell membrane balanced so it’s not too fluid like or solid. It is also very important to the membrane as its keep it stable and without the cholesterol the membrane would break and the cell will burst open. Protiens- The cell membrane plays host to the protein as it is one of the more popular parts of a membrane that is responsible for its many different activities. Protiens are very important in a membrane as they have many tasks, most of the proteins act as transport proteins. These are used for bigger molecules like polar molecues and ions. There are a different variety of proteins each one for a different type of ion or molecule and they each control what enters and leave the cell. An important type of protein within the cell membrane is the globular protein. Unlike the proteins that only play a structural task, globular proteins work as enzymes, messengers, transporters and supply of amino acids. Some proteins molecules move around with the phospholipid layers whereas some proteins are fixed inside the cell and don’t move and some proteins are also fixed in the outer layer there are also some in the inner layer and proteins around with the whole membrane. Other proteins could also act as enzymes. Protiens are also important in the roles in the membrane s of organelles. E. g. Membranes of mitochondria and chloroplast, as they are involved in the process of respiration and hotosynthesis. Glycolipids- Many molecules including glycolipids on the surface of the membrane have carbohydrate chains connected to them. This combination is known as glycolipids or if a protein is attached then glycoprotein. Environmental Conditions on a Cell Membrane- The phospholipid bilayer is affected when the temperature of the environment it is in is incr eased on the membrane. When the temperature of the membrane is increased the protein starts to denature when the temperature is increased to about 35/45 Â °c and more. Once the proteins have started to denature they gradually start to change shape therefore the shape of the phospholipid bilayer also starts to change shape. At this stage the proteins haven’t fully denatured, but when the temperature is raised to about 65/70Â °c the protein will be fully denatured. Therefore as the protein has completely been denature, the shape of the protein will be completely deformed so, therefore it won’t fit properly into the phospholipid bilayer. Due to this, gaps will appear, making it more permeable. Similarly with the phospholipids, they don’t denature but as the temperature is increases they gain more energy and as a result of this they start to move around. This will cause fluidity of the membrane. This will make gaps and cause it to become more permeable. (References: Biology 1- Mary Jones, Richard Fosbery and Dennis Taylor, http://en. wikipedia. org/wiki/Cell_membrane) Prediction As you can see I have done some research about plasma membranes and its components and I have come to a prediction on what I think will happen and what results might show when I have completed the experiment. I simply predict that the greater the temperature on the beetroot sample the less light will pass through the beetroot sample when it is in the calorimeter and the lower the temperature is more light will pass through the beetroot sample. I have predicted the above because once the temperature is raised to about 35/45 Â °c the proteins in the phospholipid bilayer start to change shape and once the temperature has been raised to about 65/70Â ° the shape would have completely changed and the protein would have fully denatured and the proteins embedded in the phospholipid bilayer will not be able to fit in the bilayer properly. As the temperature is increase not only will the proteins get denatured but the phospholipids will gain energy therefore will start to move faster and the phospholipids will gain fluidity and this will also increase the rate in which permeability is taking place. Therefore, for these particular reason gaps will be made in the phospholipid bilayer due to the denatured proteins and the movement of the phospholipids. As a result, the increase in temperature will have caused damage to the plasma membrane and this will let the red/purple pigment of the beetroot sample (betacyanin) out from the vacuole in which it is held in. Apparatus Beetroot- I am going to use this as I am going to test the permeability of the beetroot cell. Scapula- I will use this to cut the beetroot. Ruler- This will be needed to measure the beetroot. Beaker- I will use this as a water bath and to heat the test tubes in. Pipette- I will use this to get an accurate 4cm? sample of beetroot. Test tube- I will use this to put 15cm? of distilled water and beetroot. Distilled water- I will use this for the experiment as the tap water could have other chemicals for example chlorine. Calorimeter- This will be used in the experiment to calculate how much light is transmitted through the beetroot sample. Cuvette- This will be used to but the sample of beetroot in and put in the calorimeter. Bunsen Burner- This will be used to heat up the water bath. Thermometer- I will use this to measure the temperature of the test tubes in the water bath. Measuring cylinder- I will use this to measure out 15? of distilled water. Cork borer- I will use this to extract small pieces of the beetroot out of the actual one Test tube rack- I will need this to hold the test tubes. Timer- I will need to time how long I have kept the beetroot in the distilled water. Goggles- I will need to wear these so nothing enters my eyes Risk Assessment Equipment/SubstanceRiskReduction/Emergency Action ScapulaRisk of getting cutBe as careful as possible and if cut wash the cut in case of infection and use a first aid kit Bunsen BurnerRisk of getting burntTie hair back, wear goggles and if burnt then put the area which is burnt under cold water Hot waterRisk of getting burntIf burnt, place burnt rea under cold water Beetroot SolutionRisk of entering eyeTo prevent this wear goggles and if it enters eyes wash out with warm water Cork BorerRisk of getting cut Method To begin with I will use a cork borer and get 15 pieces of beetroot and use a ruler to measure each piece 2cm long and cut it using a scalpel as I will be using 5 different temperatures (25Â °c, 35Â °c, 45Â °c, 55Â °c, and 65Â °c). I will repeat each temp erature 3 times. Each piece of beetroot will have to be of the same size to make it a fair test and that is also why I will repeat each with temperature 3 times. Secondly I will then rinse the equal pieces of beetroot with distilled water and dry them as while cutting the beetroot cells could get damaged and therefore betacyanin would be on the samples and this would not be a fair test. After that I will then measure 15cm? of distilled water into a measuring cylinder and pour it out into a test tube. I will repeat this three times. After that a Bunsen burner will need to be set up and as it is a dangerous piece of equipment I will need to wear goggles when using it. Once the Bunsen burner is ready to use I will fill a beaker up with 150 cm? f water and as I will be using the water beaker as a water bath for the test tube I will need to use a tripod and put gauze onto top of it. I will then place the beaker on top of the tripod and on the Bunsen burner. After this I will put the test tubes into the beaker to get the water to the correct temperature. To analyze the temperature I will place a thermometer a test tube till it reaches the first tem perature of my choice which will be 25Â °c. Once the temperature reading is 25Â °c I will remove the Bunsen burner from underneath the beaker. Then I will pace the three test tubes in a holder and at the same time will put 1 beetroot piece in each test tube and keep them all in for four minutes, i will time it using a timer. When four minutes is over I will stir the beetroot solution so no pigment is left at the bottom of the test tube. Using a pipet I will extract 4cm? from each of the solutions and put them into a cuvette, but is important not to touch the cuvette where there are no arrows as that is where the light transmits through. Finally I will use the calorimeter to measure how much light is transmitted through the beetroot samples. But before putting each sample into the calorimeter I will put a sample of distilled water which should measure about 100 so that I will know that the calorimeter has correctly been adjusted. I will repeat this three times for each temperature. I will repeat this procedure all together five times as there are five temperatures, (25Â °c, 35Â °c, 45Â °c, 55Â °c, and 65Â °c) and test one temperature three times just as this is mentioned above.

Physician and American Golfer Tom Essay

Physician and American Golfer Tom Essay Physician and American Golfer Tom Essay Blaming the Doctor For physicians a god like perspective is brought forth by society. Brain Goldman explains this in his video â€Å"Doctors make mistakes. Can we talk about that?’ Goldman puts very simply that if a baseball player clears the ball 3 out of 10 times its good, and if he can clear it 4 out of 10 times he’s amazing, but in the medical world what would truly want are doctors or surgeons only to do things right 4 out of 10 times. The answer is no! When it comes to are health or even the health of our loved ones we want absolute perfection. As a society I believe we are to blame for the needs of doctors to cover up misdiagnosis, and take firm belief that medical inaccuracies could be lessened if doctors were able to admit mistakes freely without fear of what the outcome could be. American golfer Tom Watson captured the world's attention. If he had won at age 59 he would have been the oldest winner of the golfing championship. He captured my attention after he narrowly lost. Watson could have blamed his caddy, his clubs, or loud fans for his defeat. Instead he said plainly, "I put myself in a position to win but I did not get it done." He admitted that the errors leading to his defeat were his alone. If only more physicians had that same sense of responsibility about owning up to medical errors. It's easy, for example, to shrug off hospital infections. A decade ago, the Institute of Medicine published "To Err Is Human," a ground-breaking report that focused on the epidemic of medical errors in the U.S. Some of the nation's most respected physicians wrote it, and many doctors endorsed it. The report recommended changing hospital and physician practices to reduce errors. Those recommendations included publicly disclosing errors and safety concerns. Since then, b illions have been spent studying the problem, but not much has Tens of thousands of people continue to die each year because of errors. It's difficult or impossible to determine who or what was responsible for a medical mistake or hospital-acquired infection. But often we know that an error was the culprit, not the disease or the patient. Administrators worry that if they acknowledge errors, doctors and staff will be afraid to report them. But is that fair to patients who might have been harmed? They deserve to know what happened. The patients and families deserve an apology from staff who take responsibility for the error. Until our health-care system gets its act together, patients and their families will have to be constructively assertive to get to the bottom of any mishaps In an ideal world, the only factors that would go into a physician's decisions would be his or her years of clinical training and an assessment of what's best for the patient. Unfortunately, healthcare isn't that simple. A

Manned mission to Mars Essay Example | Topics and Well Written Essays - 1000 words

Manned mission to Mars - Essay Example Moon is the natural satellite of earth which is located near to the earth compared to other planets. Only Neil Armstrong and Buzz Aldrin were able to land on moon so far even though many other satellites were send to moon for explorations. The access to moon is still not easy for the humans. Under such circumstances manned missions to Mars has made lot of controversies. Some people argue that manned missions to mars are the only way to find more things about our neighboring planets and to explore the possibilities of any life there. Moreover, only manned missions will be able to prove beyond doubt that how useful the external planets for human beings. On the other hand, critics believe that manned missions to mars is a risky topic because of the immense possibilities of danger both on the way and while landing on moon. This paper briefly analyses the arguments in favor and against manned mission to mars Critics of manned mars mission have raised three major questions; a) how to get funding?, b) how to land on Mars safely?, and c) how to ascent from Mars safely? (Heinonen). It is not easy to send manned spacecrafts to mars. Billions of dollars are needed for mars exploration. It is practically difficult for a single country to bear such huge expenses. But somehow if we are bale to manage the expenses for manned mission, the second question is how to land safely on mars. We have less knowledge about the atmosphere and others dangers waiting for us in Mars. Even the landing on moon was not easy for us even though we did succeed once. Many people believe that high energy cosmic rays and other ionizing radiations might be available in Mars. Moreover, mars have low gravity than earth which may cause further problem to the explorers. The third major cause of concern about manned mars mission is the question of how to ascent from mars even if we succeeded in landing safely on mars. On the other hand,

Modeling and Role Modeling Essay Example | Topics and Well Written Essays - 1000 words

Modeling and Role Modeling - Essay Example One of those foundation theories was Maslow's hierarchy of needs. Modeling is gaining an understanding of the clients world from the clients perspective. It assumes that all humans want to interact with others and quality holistic care is one of the goals. The propositions are the degree to which development tasks are resolved and is dependent on the degree to which human needs are satisfied and the ability to cope is directly related to the level of need satisfaction. It enhances the nurses ability to understand the worldview of adolescents and to use this gained understanding to design health education programs that address the adolescents development needs (Bray, 2005). The theory enables nursing to care for and nurture each client with an awareness of and respect for the individuals uniqueness and focus on that clients needs. Clients have the intelligence and ability to understand what has made them sick as well as what the plan is to make them well. Let's take the example of a young person who is admitted to the hospital with diabetes. She is readmitted regularly because she is out of control. When the nurse sits down to talk with her about her diabetes, she says she just wants to be like her friends and she does not want to say she can't have it when they go for a hamburger and fries. She just wants to feel normal. In this case, according to Erickson's model, the patient needs to be understood in her world, not in the world of the nurse (Arruda, 2005). When placing the nurse in that world she understands the pressure to be like her friends and try not to worry about her diabetes all the time. The nurse determines two interventions. She talks wit h the nutritionist to come up with a diet plan for the patient that would include the kinds of foods that a young person of that age likes to eat and she talks with the doctor about the possibility of an insulin pump. The nutritionist does come up with a plan that meets the young lady's needs and leaves some open space that she could fill with something like a shake if she went out with friends. An insulin pump is put in place (Sappington, 1996). The nurse has accomplished filling the patients needs while also assuring her understanding and buy in to meeting the needs of her disease This would of course be measured by the patient maintaining control and not being readmitted which she has not. There are five common goals of this theory and each of them was met in this case. Those goals are building trust, promoting positive orientation, promoting perceived control, promoting strengths and setting health directed mutual goals. Nursing retention is one of the greatest issues in healthcare today, with ageing nurses, and a shortage of new nurses, everyone wants to keep the ones they have. Modeling/ Role Modeling lends itself well to leadership decisions in healthcare. The client is the center of the theory. In this case, the client is the nurse. In understanding the nurses world we find what are the things that she needs most. We use Maslow's hierarchy of need and the five common goals of all interventions which again are trust, promoting positive orientation, promoting perceived control, promoting strength and setting directed mutual g

Global Warming Essay Example for Free

Global Warming Essay Among The most profound environmental problems, Global Warming is one of the serious problem. Former vice president Al Gore takes his environmentally friendly political agenda to the big screen with the documentary ‘An Inconvenient Truth’. The film follows Gores platform of recognizing global warming as a worldwide problem. Gore says the truth must be revealed or there will be consequences to pay . Since the beginning of Industrial Revolution, atmospheric concentration of CO2 have increased by 30%, Methane concentration by 100% and Nitrous oxide concentration by about 15%. These increases have enhanced the heat trapping capability of the Earth’s atmosphere. The combustion of coal, oil and natural gas accounts for most of the heat trapping greenhouse gases emitted by human activities. Most of the best and brightest in the world scientific community, however, believe we are heading for the trouble. But coal and petroleum products are abundantly used for moving the life cycle of people. Asking such people to slow down or choose more expensive alternative energies is asking for trouble. Petroleum industry is very big industry In which there are millions of people employed and the millions of families thriving on this for their livelihood. To find out the solution of Global Warming merely alleging the petroleum industry and burning of fossil fuels then those millions of people who are depending on these industries are badly affected. There are so many other causes also which are responsible for the Global Warming like industrial revolution, nuclear radiations and emitting of green house gases. 98% of total global greenhouse gas emission are natural, mostly water vapour; the effect of water vapour is not well understood. Some of the critics of Al Gore’s ‘Inconvenient of Truth’ says â€Å" An Inconvenient Truth, Al Gore makes absurd remarks about global warming that stretch well beyond the IPCC claims. This clip demonstrates some of Gores various exaggerations on the subject of global warming†. There could be benefits in the wake of the planet’s warming. Increased rainfall, created by climatic fluctuations, in a semi arid region will raise agricultural productivity. Rising CO2 levels cause plants to grow faster and absorb more CO2, through photosynthesis. Longer growing seasons may boost yields in northern Canada and Europe. In fact, a vast majority of scientists now believe that even an immediate and dramatic cut in global greenhouse gas emissions would not fully prevent climate change impacts. Even USA, world’s largest emitter of greenhouse gases, is not willing to be subjected to any kind of restraint on their energy use. USA has not ratified the Kyoto Protocol. The country claimed that if it has to implement the provisions of the Protocol, the economic losses will be heavy and will drive 5 million Americans out of work. Policies to promote energy efficiency, in the long run, will improve economic performance, at the individual firm or country level. Global warming is a global problem calling for global solutions; no nation alone can defeat the problem. Industry must develop energy – efficient vehicles, consumer goods and production processes. â€Å" Most important, individual households must contribute to emissions reduction through their power of consumer choice and their personal lifestyle decision†. Reference: With inputs from â€Å" Is Apocalypse Near, Far or Never? † by G. Vijaya Raghavan V S M Nair.

Acid Rain :: science

Acid Rain INTRODUCTION: Acid rain is a great problem in our world. It causes fish and plants to die in our waters. As well it causes harm to our own race as well, because we eat these fish, drink this water and eat these plants. It is a problem that we must all face together and try to get rid of. However acid rain on it's own is not the biggest problem. It cause many other problems such as aluminum poisoning. Acid Rain is deadly. WHAT IS ACID RAIN? Acid rain is all the rain, snow, mist etc that falls from the sky onto our planet that contains an unnatural acidic. It is not to be confused with uncontaminated rain that falls, for that rain is naturally slightly acidic. It is caused by today's industry. When products are manufactured many chemicals are used to create it. However because of the difficulty and cost of properly disposing of these products they are often emitted into the atmosphere with little or no treatment. The term was first considered to be important about 20 years ago when scientists in Sweden and Norway first believed that acidic rain may be causing great ecological damage to the planet. The problem was that by the time that the scientist found the problem it was already very large. Detecting an acid lake is often quite difficult. A lake does not become acid over night. It happens over a period of many years, some times decades. The changes are usually to gradual for them to be noticed early. At the beginning of the 20th century most rivers/lakes like the river Tovdal in Norway had not yet begun to die. However by 1926 local inspectors were noticing that many of the lakes were beginning to show signs of death. Fish were found dead along the banks of many rivers. As the winters ice began to melt off more and more hundreds upon hundreds more dead fish (trout in particular) were being found. It was at this time that scientist began to search for the reason. As the scientists continued to work they found many piles of dead fish, up to 5000 in one pile, further up the river. Divers were sent in to examine the bottom of the rivers. What they found were many more dead fish. Many live and dead specimens were taken back to labs across Norway.

Purpose of an Operating System

CPU and memory requirements are the most glaring but even hard rive partition size and what kind of disc drive present matters. Within the generations of Windows there is a long list of features that separate them. Windows XP was introduced with personalized start menu options per user using the PC. XP was the first Windows SO to self-adjust the task spacing as the user opened more programs. Windows Vista introduced Area, Sidebar, and Gadgets in an effort to enhance the users experience but also to make it easier to interact with the main system through the mini-application based Gadgets.Simple services like displaying pictures, turning wireless on or off, ND music playback were available that prior to Vista required a running program. Windows 7 further enhances the user experience with modification to Windows explorer and how it organizes the files and folders in an easier to use format. The use of Libraries enables the SO to index files by content and therefore able to group in a w ay where the user is able to locate a file even if the file is saved in an unrelated folder. The second largest of the major ASS is used exclusively by Apple.Mac SO is a proprietary system that has a very strict requirement for what hardware will work with the system. Despite the hardware limitations to only Intel Cups and approved motherboards, it remains a huge favorite to certain groups of users like multimedia designers, graphic artists, and music producers. One potential reason for this is because Apple was the first to utilize a simple a graphical user interface (GU') therefore making it easier to use the system instead of driven by often hard to use and complex DOS commands.With later versions of Mac like SO X, various technologies, such as Anti-Aliasing and Colors are used to dramatically improve the user interface. Another difference is that a user can pen PC files like . Doc and . AXIS within Mac without problem, while Windows requires conversion software to open Mac files . By doing this, Apple has in effect broken down many important barriers while the average PC user has resisted in adopting a Mac over a PC. Despite some advantages, Mac usage is low, roughly 10% or lower of the entire computer market in the U.S. The smallest market share among the ASS belongs to Linux. Users have been slow to adopt it since its inception in October of 1991 by Lines Dorval. Despite little use by average users, there exists many a version or distributions which ghastly dominate the area of computers known as servers, main frames, and super computers. Linux is also the system of choice on much smaller devices like phones and tablets. What makes Linux exciting to use for some is also what keeps most users away; Linux has splintered to over 300 variations.Most are specialized for the devices which it is meant to be installed on, but even for use for the mass market of users there are still four major variations such as Bunt, Use, Red Hat, and Knops. Common trait within Linux is that it has a very small footprint compared to larger ASS like Windows. For computer enthusiasts, one can run a distribution of Linux on hardware that is otherwise vastly outdated or run alongside Windows on the same computer.Another advantage of Linux is the well-established and openly accessible documentation on the commands but also how to configure the System best for the user or the use of the SO as well as how to troubleshoot issues. For software hobbyists and professionals this means that they can basically tailor the system to their needs and cut the dependence on what Microsoft or Apple may offer. Because of the open source nature of the SO, they can both upload fixes and receive enhancements from other users and the committees that oversee Linen's development.Despite the differences between operating systems a common thread among them is that they help shape the user experience of a computer. By doing so it enhances our desire to continue using computers and their many benefits. Without development of operating systems things such as modern day networks or communications wouldn't be possible. Since new technologies are constantly bringing us new and better hardware, it's the operating system and its development that will continue to encourage the user to ultimately enjoy the device.