Peter Mitchell (1920 - 1992) Chemiosmotic Hypothesis Essays

Peter Mitchell (1920 - 1992) : Chemiosmotic Hypothesis Peter Mitchell's 1961 paper introducing the chemiosmotic hypothesis started a revolution which has echoed beyond bioenergetics to all biology, and shaped our understanding of the fundamental mechanisms of biological energy conservation, ion and metabolite transport, bacterial motility, organelle structure and biosynthesis, membrane structure and function, homeostasis, the evolution of the eukaryote cell, and indeed every aspect of life in which these processes play a role. The Nobel Prize for Chemistry in 1978, awarded to Peter Mitchell as the sole recipient, recognized his predominant contribution towards establishing the validity of the chemiosmotic hypothesis, and ipso facto, the long struggle to convince an initially hostile establishment. The seeds of the chemiosmotic hypothesis, which lay in Peter's attempts to understand bacterial transport and homeostasis, were pollinated by the earlier ideas of H. Lundergard, Robert Robertson, and Robert Davies and A.G. Ogston, on the coupling of electron transport and ATP synthesis to proton gradients. Mitchell's 1961 paper outlined the hypothesis in the form of several postulates which could be subjected to test. In retrospect, it was a great strength of this first paper that Peter did not go into too much detail; the ideas were new and strange, and were introduced to a field dominated by a few major laboratories with their own different ideas about how the coupling between electron transport and phosphorylation occurred. It is interesting to look back and remember how sparse the clues were on which the hypothesis was based. At the time, the chemical hypothesis, based on analogy with Ephraim Racker's mechanism of substrate level phosphorylation linked to triose phosphate oxidati on, seemed secure. A few niggling difficulties were apparent. Why did so many different reagents act as uncouplers? Why were the enzymes of oxidative phosphorylation associated with the mitochondrial membrane? Why did coupling seem so dependent on the maintenance of structure? How did mitochondria maintain their osmotic balance? How did substrates get in and out? But these must have seemed second-order problems to the main protagonists. It was these niggles that Mitchell's hypothesis addressed. I first met Peter in 1962 when he visited Brian Chappell in Cambridge to talk mitochondriology. I was in my second year of Ph.D. research, and becoming familiar with the field. Brian had, at the start of my apprenticeship, set me to work in the library, with Peter's 1961 paper as a starting point. I must confess that I had little idea at the time of the importance of the paper; I didn't know enough, either of the background bioenergetics or the physical chemistry, to understand what the issues were. But by the time of Peter's visit, I had become involved in the work on mitochondrial ion transport initiated by Brian in collaboration with Guy Greville, and Brian had become interested in mechanisms. Peter arrived in an elegant if ancient Bentley convertible, and wrapped us in a corduroy enthusiasm. He was in trouble with his hypothesis, because three labs claimed to have disproved it by isolating the intermediates expected from the chemical hypothesis. Peter was undaunted, and engaged i n a mischievous discussion of the data and its validity. The challenge of the upstart chemiosmotic hypothesis to the prevailing chemical view of mechanism was to become a running battle, in which Peter engaged the establishment single-handed for several years before the first of a growing band of brothers (and sisters) joined him in the fray. The early work from Andr? Jagendorf's lab on H+-uptake and pH-jump driven ATP synthesis by chloroplasts, the parallel work on ion and metabolite transport in mitochondria from Chappell's lab, the work on ionophores and uncouplers by Bert Pressman, and by Brian Chappell and myself, the development of artificial membrane systems by Alec Bangham and by Paul Mueller, and Mitchell's own work with Jennifer Moyle on proton measurements following O2 pulses, had demonstrated before 1965 the activities expected from the hypothesis, but it was to be ten years before the established leaders in the field were coaxed into a grudging acceptance of the hypothe sis. The bones of the chemiosmotic hypothesis were fleshed out by Mitchell in subsequent publications, most notably the two slim volumes published by Glynn Research Ltd. in 1966 and 1968, known affectionately in the laboratory as

Conserving Energy - Renewable and Non-Renewable Resources essays

Conserving Energy - Renewable and Non-Renewable Resources essays Conserving energy is important, since the world will not be able to depend on nonrenewable resources in the future. Nonrenewable resources are resources that cannot be replaced such as natural gas, coal, and oil. Conserving energy will lessen the need for nonrenewable resources, which will be beneficial to the environment, by helping to preserve more natural environments. Energy allows humans to live comfortable lives by powering our modern day conveniences. Automobiles and electricity are two common items that are dependent on a steady stream of energy. Energy consumption around the world has been on an increasingly uphill climb, for many years now. Society needs to work towards understanding and utilizing renewable resources because nonrenewable resources are depleting, which will eventually lead to zero resources for energy. Nonrenewable and renewable are words used to define various natural resources. A renewable resource is a natural resource that when used can be replace such as wind, trees, and water. Renewable resources are highly sought out because of their ability to reproduce, when more is needed. Renewable energy is viewed as safe for the environment, when compared to the hazards of nonrenewable resources. Nonrenewable resources are found in chunked amounts, and are used up more rapidly than the replacement rate. Although there are nonrenewable resources found in nature, these are deemed more harmful to the environment than renewable resources. Nonrenewable resources are non-replaceable as soon as these are used, which makes these an unfavorable source of energy when compared to the benefits of renewable resources. Conserving energy helps the environment and can help people save money. An action such as turning off a light contributes to conserving energy. Limiting shower durations, using energy efficient light bulbs, and unplugging appliances when n...

What Are the Benefits of Earning an IB Diploma?

In past posts on the blog , you may have noticed that when we talk about AP courses and exams , we sometimes mention another acronym that may not sound as familiar to you: IB. This stands for International Baccalaureate , and represents another advanced educational option for high school students that exists alongside the AP program. While the IB program isn’t as popular as the AP program in the United States, it can definitely be a worthwhile option for those who have access to it. In particular, earning an IB diploma, which requires that you take certain courses and fulfill additional academic and extracurricular obligations, can be an impressive qualification to add to your resume. Read on for more information about the IB Diploma Programme and how an IB diploma can enhance both your high school experience and your college prospects. International Baccalaureate is an overarching organization that administers a number of different educational programs for students ages 3 to 19. Its curricula are used by specially trained teachers at certified schools throughout the world, and it prides itself on providing â€Å"rigorous, high-quality education† to its students. The most familiar IB program to high school students in the United States is the IB Diploma Programme, or IBDP, which is offered to students between the ages of 16 and 19. When you hear about â€Å"IB courses† being offered at a high school, it means that that school has been certified to offer the IBDP. (Students may be able to take some IB courses without enrolling in the full IBDP curriculum.) In some ways, the IB program is similar to the AP program—it’s a way for high school students to take advanced, rigorous courses. However, there are two main differences. For one thing, the IB program is much less popular than the AP program among high schools in the United States, and you since you can’t self-study IB courses, its availability is limited. In addition to this, the IB program is far more focused on presenting a cohesive overall curriculum with specific requirements that culminates in a diploma. While the AP program offers a similar option in the AP Capstone Diploma , most students don’t approach the AP program in that way. For a more detailed explanation of the International Baccalaureate organization, and especially the IB Diploma Programme, check out the Beginner’s Guide to the International Baccalaureate Program . The IBDP is a two-year academic program that, as we’ve mentioned, is open to students aged 16 to 19—in other words, high school students. Upon successfully completing the program and all its requirements, students can earn the IB diploma, which is a significant credential for college applications and other purposes. Academically, the IBDP requires students to take courses and pass exams in six specific subject areas. Three or four of these subjects must be taken at the more challenging â€Å"Higher† level, while the rest can be taken at the â€Å"Standard† level. In addition to this coursework, the IBDP has three more major requirements. First, students must write a lengthy essay based on independent research. Second, students must take a Theory of Knowledge course, which covers critical thinking and epistemology. Third, students must participate in a certain number and range of extracurricular activities. Earning the IB diploma means that you’ve done much more than take a few IB courses. Instead, you’ve undertaken a particular kind of high school education that is meant to teach you not only history, math, and other subjects, but also how to better analyze and understand the information you’ll encounter in school and beyond. Along with this stated purpose, an IB diploma can be an asset for you in a number of different ways, especially as you take on the college admissions process. Below, we’ll go over some of the main benefits of working toward and receiving an IB diploma. Our Early Advising Program helps students in 9th and 10th grade discover their passions and build strong academic and extracurricular profiles to succeed in high school. The IBDP is well-known throughout the world for the high quality of the coursework it offers. The strength of the IB curriculum, as well as the extensive training that IB teachers and school administrators are required to undergo, help the program to maintain this high standard. The respect that the IBDP enjoys means that no matter where you go, colleges will understand and positively view the effort you’ve put into earning your IB diploma. College admissions officers in particular will be familiar with the program’s reputation, making an IB diploma an excellent way of demonstrating your academic prowess. Strong performance in school is, of course, an important component of what competitive colleges look for in applicants. This is typically represented in your application by your GPA , transcript, and class rank. However, since every high school is different, colleges can’t always be sure what your grades actually mean compared to those of other applicants. Programs like the IBDP help colleges to evaluate applicants by providing a single curriculum that’s used worldwide, allowing admissions officers to more precisely assess your performance. Since this program is known to be rigorous, doing well in your IB courses and earning your IB diploma indicates to colleges that you’re an objectively strong student. Earning an IB diploma also shows you’re willing to take on special academic challenges. You’ve chosen to go beyond the typical high school curriculum and pursue a goal that asks more of you, including substantial independent work on topics of your own choosing. This is something that every competitive college values. As we’ve mentioned, the IB program is less popular and well-known in the United States than, for example, the AP program. You must take IB courses at a certified high school—self-studying is not allowed—which limits the number of students who can participate. The expense and training required to get certified as an IB school can also contribute to its relative rarity at high schools. What this means for you is that if you have an IB diploma, you’ll be among a relatively small portion of the college applicant pool with this qualification.   This distinction shows that you’ve not only taken on academic challenges, but done so through a program that’s widely known to be reputable and rigorous and require a good deal of independent work from its graduates. Not every student can present such a prestigious qualification when they fill out their college applications, and this relative uniqueness is an advantage. In addition to the novelty of IB participation itself, certain elements of the IB Diploma Programme may give you the opportunity to do especially interesting and original academic work that will give you additional chances to set yourself apart from other applicants. As we mentioned, you’re required to complete a substantial independent research project in order to receive your IB diploma. Your choice of topic for this project can say a lot about you, and your ability to handle the challenges of independent work and create something truly original will render you a unique and recognizable candidate come application season. One particular perk of the IB program is that it can be useful not only in the college application process, but also once you get to college. Like AP test results , your IB courses can sometimes be used by colleges to determine placement and credit. Depending on your school, you may be able to be placed in higher-level courses as a result of your IB experience, or you might receive credit outright for your IB courses, which can enable you to save time and money in getting your degree. Colorado and Texas have even passed laws requiring colleges in those states to award college credit to students with IB diplomas. If you’re interested in attending college outside the United States full-time (as opposed to on a short-term basis as a study abroad student), an IB diploma may be particularly useful to you. Since other countries have different academic systems and pathways to a university education, it can be difficult for students from the US to gain entrance. The international recognition of the IB diploma can help to bridge this gap. Some examples of countries that accept the IB diploma for entrance into universities are France, Spain, Italy, India, and Turkey. Additionally, some universities offer scholarships specifically for IB diploma holders. While each country and school has additional requirements you’ll need to meet, an IB diploma can be of great help in the process. Finally, aside from college admissions concerns, getting your IB diploma can simply be a very satisfying intellectual experience in its own right. The IB program is designed not only to provide you with rigorous course content, but also to help you learn how to think, analyze, and critically consider materials in the way that your college will eventually expect. The independent projects that are part of the IB curriculum can be enjoyable as well. Some high school students don’t get many opportunities to focus their energies on the topics they consider interesting. Studying a topic that really moves you can bring out your intellectual best in a way that your daily classwork may not. Going through the full IB Diploma Programme isn’t for everyone, and as we mentioned, it isn’t available everywhere. If you have access to this option, however, it can be a strong addition to your college application profile as well as an aid to your intellectual development. You can find more advice on whether IB is right for you and handling your IB coursework in these posts from the blog : To learn more about IB, take a look at our Ultimate Guide to the International Baccalaureate Program . You can also visit the official International Baccalaureate website at www.ibo.org . Looking for more personal assistance with managing your high school goals? Check out our Student Mentorship Program to see how our experienced near-peer mentors can help you to identify your passions and prepare for the college application process.

International criminal court Essay Example | Topics and Well Written Essays - 250 words

International criminal court - Essay Example There are several reasons for this inability of national institutions, such as, first, the absence of political will to prosecute their own citizens or high ranking officials. This situation was witnessed in the former Yugoslavia. Second, these national institutions could have been destroyed, as was the situation in Rwanda. In the absence of justice there cannot be peace, without law no justice, and when there is no court to decide what is just and lawful there can be no meaningful law (United Nations, 1999). An international criminal court achieves justice for all, ends impunity, helps in ending conflicts, remedies the defects in ad hoc tribunals, provides an alternative to national criminal justice institutions that are unable or unwilling to act, and to acts as a deterrent for future war criminals. In reality, the ICC has not achieved greater success than the ad hoc tribunals that it supplants. Akin to the tribunals of Rwanda and Yugoslavia, the ICC does not act swiftly. Moreover, it is devoid of a system for enforcing its decisions. This makes it dependent upon governments to arrest and present perpetrators before it. Albeit, the ad hoc tribunals had this defect, they were able to rely on a UN Security Council resolution requiring international cooperation in executing the arrest warrants. In addition, the ICC is devoid of forceful checks on its authority (Schafer & Groves, 2009). Theoretically, the nations that had ratified the Rome Statute were to control the ICC; however, this has not been realized in practice. Schafer, B. D., & Groves, S. (2009, August 18). The U.S. Should Not Join the International Criminal Court. Retrieved May 17, 2015, from The Heritage Foundation:

Explain how new products are diffused through a marketplace, and Essay

Explain how new products are diffused through a marketplace, and identify the different groups involved in the process - Essay Example In simpler words, the willingness to buy a product at a particular time is different for different people. The first ever contribution to the field was provided by Everett Rogers in 1962. He defined diffusion as ‘the process by which an innovation is communicated through certain channels over time among the members of a social system’. The figure below provides a brief understanding of the diffusion of innovation process curve. This curve categorises people and organisations according to the willingness of the people to buy the product and adoption of the innovations. To further gain a better understanding of the various stages that have been displayed above the following sub sections will deal with the characteristics of the each of the groups. As has been noted in the figure, and as suggested by Roger, the five broad characteristics for each of the categories are as under: a) Innovators: The people who fall under this category are generally very venturesome. The people who fall into this category generally tend to be different and like to have the latest versions of all new products and are willing to be the first to experiment the new products. These people tend to be the younger population of the markets. The general characteristics of these groups are that they are highly educated, with high levels of confidence, and highly affluent financially. The fact that the groups are affluent financially, allows them to be able to test with the products and take chances. Considering the innovators of organisations, generally fall into the companies with better educated management. The reasons for these groups to adopt newer innovations is the fact of their own god track record in introducing newer products to the markets and the need to be updated with the latest in the markets. b) Early Adopters: This is the second group of people in the market. These groups do not tend to be very venturesome like the innovators.

A Comparison Of Two Poems About Soldiers Leaving Britain To Fight In T :: essays research papers

The two poems I am comparing are "Joining The Colours" by Katherine Tynan and "The Send Off" by Wilfred Owen. " Joining The Colours" is about a regiment of soldiers leaving Dublin in August 1914 to go to France to fight. This was at the beginning of the First World War and all the soldiers were happy because it was an opportunity for them to show their girlfriends and their families that they were brave. "The Send Off" is about a regiment of young soldiers who are departing later in the war. This poem was written a few years after "Joining The Colours". The mood of each occasion is different because "Joining The Colours" was written when the soldiers and their relative's thought that the war would be over by Christmas but instead it finished much later on and millions of soldiers got killed. The mood in "The Send Off" is totally different because the soldiers were already afraid. They knew how dangerous the war was because of what so many people had experienced since "Joining The Colours" was written in 1914. There was no celebration for them because most of the people knew what was going to happen. The structure and the style of each poem varies in different ways. "Joining The Colours" is more positive. The structure of this poem is simple. Even though there are some words which convey an image that war is bad, most of the style of writing is positive and even happy. "The Send Off" is a more serious and frightening poem. The style of writing throughout the poem is sad and conveys an image that war is completely bad. The structure of this poem is more complicated than "Joining The Colours". This is because the poet is trying to convince the reader that war is the most terrible thing that ever happened.In "Joining The Colours" the soldiers seem happy as they march to war. In stanza 1 for example "There they go marching all in step so gay". This quotation shows how they enjoy marching, all together. Their attitude towards war is very carefree. They look almost as though they are "going to a wedding day". In stanza 2 the soldiers "are singing like the lark". In stanza 3 they make noises with "whistles, mouth-organs". The soldiers are carefree because they are brave. They don't understand how dangerous war is because they are too young.

Hoovers policies and attitudes in the years 1929-33 Essay

Asses the view that Hoover’s policies and attitudes in the years 1929-33 merely prolonged the depression. President Herbert Hoover came in to power in America in 1928. He was a man with a strong belief and he believes in individualism and believed passionately in the values of hard work and enterprise. However, he came in power at a time where America was in an economic crisis, where unemployment was shooting up as well as inflation, America had entered a new era where inequality was increasing more than ever for example New York had one million unemployed whereas Ohio has 50% of the population unemployed, thus it was vital for Hoover’s policies to be adequate in order to restore prosperity. Source 7 clearly argues that Hoover’s attitudes and policies were inadequate and â€Å"failed again and again†. Similarly, source 8 believes that his faith in his own policies has only prolonged the depression even more, thus both sources have a clear consensus between them. On the other hand source 9 argues that a lot was actually done in order to get Americans back on their feet, thus Hoover’s attitudes and policies were good for America. However, it is clear that Hoover simply did not do enough in order to deal with this economic crisis as he was seen to be as a very â€Å"stubborn† person as source 7 argues and he simple could not read between the lines. Source 7 describes Hoover as a very stubborn person who â€Å"Remained convinced that he was right† Hoovers attitudes towards agriculture did not help American farmers at all. The agricultural marketing act was established in 1929 which artificially purchased farmers surpluses at prices above the market price. Hoover gave the Federal Farm Board $500M, yet Hoover still not think through exactly what he was doing. The agricultural market was in a significant decline in America during the 1930s and he only encouraged farmers to produce more as the Federal Reserve board was purchasing their surpluses. Furthermore, he was accused of throwing away tax payers money which was extremely regressive. Similarly, source 8 believes that Hoover undertook some â€Å"harmful policies† where he also â€Å"resisted congressional attempts to provide more substantial farm relief† this can be seen through the fact that instead of putting money into farmer’s pockets he actually took it away. Farming was seen as the backbone of the American economy and Hoovers Agricultural Marketing Act seemed like something that was rushed and never thought through which emphasises how Hoover simply lacked knowledge in many areas of the economy. Furthermore, he never thought about agricultural on an international level and the consequences his actions would have, thus his attitudes towards individualism was clearly not applicable to American society at that time as American clearly needed a Keynesian approach towards the economy where money would be significantly pumped in to the circulation of the economy. Source 8 also believes that the Hawley-Smoot Tariff was significantly damaging towards Americans â€Å"which he signed despite the advice of most economists†. This emphasises his attitudes towards his policies, he in his own â€Å"fantasy world† as source 7 also describes as he simple did not have any fixed approach towards fixing the damaged economy. Hoover did not realise exactly what was needed for the American economy as if he did, he would have realised that putting a 40% duty on agricultural products would not have stimulated the economy. This fantasy world consisted of just his own approach, which was not thought through, he believed just because he had a very hard work ethic meant that everyone else could have one too, however, this was not the case in America as Americans simply had no money in their pockets to start them off and they needed relief in order to get back on their feet again. Furthermore, his policies had a very short run effect as he believed by putting tariffs up it would help farmers gain more revenue. However, with agriculture being such a competitive market, it only led to retaliation as countries all across Europe could not afford high prices as they were in an economic crisis too. Furthermore, the Hawley-Smoot tariff resulted in the abandonment of free trade amongst European nations, thus it was extremely damaging for the agricultural market as they could not sell their surpluses and had to eventually dump their goods in different countries, therefore Hoover did pro long the depression. Furthermore, source 8 also argues that Hoovers approach towards unemployment was also not good enough as he â€Å"blocked direct aid to the unemployed†. This is because of his hands off approach attitude that he undertook during the 1930s was not radical enough and could be seen as taking things â€Å"too modestly† as source 8 states. The Emergency Committee for Employment aimed to help agencies provide relief of $500, however, due to his self-reliance attitude he did not allow direct federal relief. This clearly shows how Hoover was not thinking ahead and his attitudes were far behind time as he did not realise exactly how badly Americans needed the governments help and it was crucial to intervene in the economy as much as possible. However, Hoovers $500M was not large enough to help the millions of people in America who were unemployed and did not have the basic necessities in life, growth was literally not possible without the government intervening as GDP was getting lower and lower. However, taking into account that many countries were in a nation debt, it was obviously not possible for Hoover to magically get a large sum of money in order to give relief to firms and other sectors, thus there was actually a limited amount that Hoover could do even though he did have a hands off approach towards America. Source 9 completely contradicts source 8 and 7 as Leuchtenburg believes Hoover â€Å"Stepped up federal construction and urged state and local governments to accelerate spending† thus Hoover did make significant changes that did not pro long the depression. One of his most significant polices was the reconstruction finance corporation which was authorised to lend $1.5 billion to states to finance public works. Not only was this a very direct relief but it also had many benefits as it helped insurance companies as well as banks. One major aspect of the RFC was the fact that it lent 90% to small and medium banks, which was a turning point as rural small banks were hardly ever noticed and no other president intervened the way Hoover did and this contradicts Patterson’s view of Hoover having â€Å"minimal government intervention†, thus his lack of intervention may have been exaggerated by source 7 and 8. The â€Å"increased capital investment† as source 9 suggests also helped the economy as investment was a crucial part of GDP and investment would have allowed firms to innovate in America, thus Hoover had noticed the â€Å"grim reality† of the depression as he was doing what he could have in order to restore the economy. However, the RFC was only available to states that declared bankruptcy and they had to use the money to provide schemes which would earn money so that loans could be repaired and this perfectly fits in with Parrish’s view of how the â€Å"economic crisis required maximum cooperation† , which Hoover was not giving at that time as all banks and businesses needed some sort of relief which he was not doing. Furthermore, even if he was cooperated it was a little too late, thus Hoover did pro long the depression. Overall, it is clear the Hoover’s approaches were not good enough for American society in the 1930s and he did pro long the depression. One vital error that Hoover made was the fact that he was not helping the unemployed as much as he should have as in order to stimulate the economy, a wage was needed and with a wage tax could have been paid which could have been used to fund the public with goods. Therefore, if Hoover had considered getting people into work this would have automatically had a positive knock on effect. Furthermore, a hands off approach was not needed in times of the depression as Americans did not have money to get back on their feet as many banks were not giving out loans due to the effects that the boom period had on them, therefore a lot of intervention was needed. Thus, it is clear that Hoover did make big mistakes during the depression as he did not see the reality of it and did not try to tackle the main problems as he had no detailed plan.