Addition of plasticisers to polymers results in partial neutralisation of intermolecular forces of attraction between the macro-molecules thereby increasing its ?->(Show Answer!)

1. Addition of plasticisers to polymers results in partial neutralisation of intermolecular forces of attraction between the macro-molecules thereby increasing its

Write Comment

Comments

Tags

Show Similar Question And Answers

QA->The attraction between similar molecules?....

QA->The attraction between dissimilar molecules?....

QA->Which river demarcate the partial boundary between South Africa and Botswana?....

QA->WhichIndian city introduced hawkers zones thereby limiting the timings for streetvendors at specific areas?....

QA->On June4, 2017, which State Government launched single-woman pension scheme across thestate, thereby becoming the first state in India to launch such scheme?....

MCQ->Addition of plasticisers to polymers results in partial neutralisation of intermolecular forces of attraction between the macro-molecules thereby increasing its....

MCQ-> Cells are the ultimate multi-taskers: they can switch on genes and carry out their orders, talk to each other, divide in two, and much more, all at the same time. But they couldn’t do any of these tricks without a power source to generate movement. The inside of a cell bustles with more traffic than Delhi roads, and, like all vehicles, the cell’s moving parts need engines. Physicists and biologists have looked ‘under the hood’ of the cell and laid out the nuts and bolts of molecular engines.The ability of such engines to convert chemical energy into motion is the envy nanotechnology researchers looking for ways to power molecule-sized devices. Medical researchers also want to understand how these engines work. Because these molecules are essential for cell division, scientists hope to shut down the rampant growth of cancer cells by deactivating certain motors. Improving motor-driven transport in nerve cells may also be helpful for treating diseases such as Alzheimer’s, Parkinson’s or ALS, also known as Lou Gehrig’s disease.We wouldn’t make it far in life without motor proteins. Our muscles wouldn’t contract. We couldn’t grow, because the growth process requires cells to duplicate their machinery and pull the copies apart. And our genes would be silent without the services of messenger RNA, which carries genetic instructions over to the cell’s protein-making factories. The movements that make these cellular activities possible occur along a complex network of threadlike fibers, or polymers, along which bundles of molecules travel like trams. The engines that power the cell’s freight are three families of proteins, called myosin, kinesin and dynein. For fuel, these proteins burn molecules of ATP, which cells make when they break down the carbohydrates and fats from the foods we eat. The energy from burning ATP causes changes in the proteins’ shape that allow them to heave themselves along the polymer track. The results are impressive: In one second, these molecules can travel between 50 and 100 times their own diameter. If a car with a five-foot-wide engine were as efficient, it would travel 170 to 340 kilometres per hour.Ronald Vale, a researcher at the Howard Hughes Medical Institute and the University of California at San Francisco, and Ronald Milligan of the Scripps Research Institute have realized a long-awaited goal by reconstructing the process by which myosin and kinesin move, almost down to the atom. The dynein motor, on the other hand, is still poorly understood. Myosin molecules, best known for their role in muscle contraction, form chains that lie between filaments of another protein called actin. Each myosin molecule has a tiny head that pokes out from the chain like oars from a canoe. Just as rowers propel their boat by stroking their oars through the water, the myosin molecules stick their heads into the actin and hoist themselves forward along the filament. While myosin moves along in short strokes, its cousin kinesin walks steadily along a different type of filament called a microtubule. Instead of using a projecting head as a lever, kinesin walks on two ‘legs’. Based on these differences, researchers used to think that myosin and kinesin were virtually unrelated. But newly discovered similarities in the motors’ ATP-processing machinery now suggest that they share a common ancestor — molecule. At this point, scientists can only speculate as to what type of primitive cell-like structure this ancestor occupied as it learned to burn ATP and use the energy to change shape. “We’ll never really know, because we can’t dig up the remains of ancient proteins, but that was probably a big evolutionary leap,” says Vale.On a slightly larger scale, loner cells like sperm or infectious bacteria are prime movers that resolutely push their way through to other cells. As L. Mahadevan and Paul Matsudaira of the Massachusetts Institute of Technology explain, the engines in this case are springs or ratchets that are clusters of molecules, rather than single proteins like myosin and kinesin. Researchers don’t yet fully understand these engines’ fueling process or the details of how they move, but the result is a force to be reckoned with. For example, one such engine is a spring-like stalk connecting a single-celled organism called a vorticellid to the leaf fragment it calls home. When exposed to calcium, the spring contracts, yanking the vorticellid down at speeds approaching three inches (eight centimetres) per second.Springs like this are coiled bundles of filaments that expand or contract in response to chemical cues. A wave of positively charged calcium ions, for example, neutralizes the negative charges that keep the filaments extended. Some sperm use spring-like engines made of actin filaments to shoot out a barb that penetrates the layers that surround an egg. And certain viruses use a similar apparatus to shoot their DNA into the host’s cell. Ratchets are also useful for moving whole cells, including some other sperm and pathogens. These engines are filaments that simply grow at one end, attracting chemical building blocks from nearby. Because the other end is anchored in place, the growing end pushes against any barrier that gets in its way.Both springs and ratchets are made up of small units that each move just slightly, but collectively produce a powerful movement. Ultimately, Mahadevan and Matsudaira hope to better understand just how these particles create an effect that seems to be so much more than the sum of its parts. Might such an understanding provide inspiration for ways to power artificial nano-sized devices in the future? “The short answer is absolutely,” says Mahadevan. “Biology has had a lot more time to evolve enormous richness in design for different organisms. Hopefully, studying these structures will not only improve our understanding of the biological world, it will also enable us to copy them, take apart their components and recreate them for other purpose.”According to the author, research on the power source of movement in cells can contribute to
....

MCQ-> Read the following passage carefully and answer the questions given below it. Certain words/phrases have been printed in bold to help you locate them while answering some of the questions. The past quarter of a century has seen several bursts of selling by the world’s governments, mostly but not always in benign market conditions. Those in the OECD, a rich-country club, divested plenty of stuff in the 20 years before the global financial crisis. The first privatisation wave, which built up from the mid-1980s and peaked in 2000, was largely European. The drive to cut state intervention under Margaret Thatcher in Britain soon spread to the continent. The movement gathered pace after 1991, when eastern Europe put thousands of rusting state-owned enterprises (SOEs) on the block. A second wave came in the mid-2000s, as European economies sought to cash in on buoyant markets. But activity in OECD countries slowed sharply as the financial crisis began. In fact, it reversed. Bailouts of failing banks and companies have contributed to a dramatic increase in government purchases of corporate equity during the past five years. A more lasting fea ture is the expansion of the state capitalism practised by China and other emerging economic powers. Governments have actually bought more equity than they have sold in most years since 2007, though sales far exceeded purchases in 2013. Today privatisation is once again “alive and well”, says William Megginson of the Michael Price College of Business at the University of Oklahoma. According to a global tally he recently completed, 2012 was the third-best year ever, and preliminary evidence suggests that 2013 may have been better. However, the geography of sell-offs has changed, with emerging markets now to the fore. China, for instance, has been selling minority stakes in banking, energy, engineering and broadcasting; Brazil is selling airports to help finance a $20 billion investment programme. Eleven of the 20 largest IPOs between 2005 and 2013 were sales of minority stakes by SOEs, mostly in developing countries. By contrast, state-owned assets are now “the forgotten side of the balance-sheet” in many advanced economies, says Dag Detter, managing partner of Whetstone Solutions, an adviser to governments on asset restructuring. They shouldn’t be. Governments of OECD countries still oversee vast piles of assets, from banks and utilities to buildings, land and the riches beneath (see table). Selling some of these holdings could work wonders: reduce debt, finance infrastructure, boost economic efficiency. But governments often barely grasp the value locked up in them. The picture is clearest for companies or company-like entities held by central governments. According to data compiled by the OECD and published on its website, its 34 member countries had 2,111 fully or majority-owned SOEs, with 5.9m employees, at the end of 2012. Their combined value (allowing for some but not all pension-fund liabilities) is estimated at $2.2 trillion, roughly the same size as the global hedge-fund industry. Most are in network industries such as telecoms, electricity and transport. In addition, many countries have large minority stakes in listed firms. Those in which they hold a stake of between 10% and 50% have a combined market value of $890 billion and employ 2.9m people. The data are far from perfect. The quality of reporting varies widely, as do definitions of what counts as a state-owned company: most include only centralgovernment holdings. If all assets held at sub-national level, such as local water companies, were included, the total value could be more than $4 trillion. Reckons Hans Christiansen, an OECD economist. Moreover, his team has had to extrapolate because some QECD members, including America and Japan, provide patchy data. America is apparently so queasy about discussions of public ownership of -commercial assets that the Treasury takes no part in the OECD’s working group on the issue, even though it has vast holdings, from Amtrak and the 520,000-employee Postal Service to power generators and airports. The club’s efforts to calculate the value that SOEs add to, or subtract from, economies were abandoned after several countries, including America, refused to co-operate. Privatisation has begun picking up again recently in the OECD for a variety of reasons. Britain’s Conservative-led coalition is fbcused on (some would say obsessed with) reducing the public debt-to-GDP ratio. Having recently sold the Royal Mail through a public offering, it is hoping to offload other assets, including its stake in URENCO, a uranium enricher, and its student-loan portfolio. From January 8th, under a new Treasury scheme, members of the public and businesses will be allowed to buy government land and buildings on the open market. A website will shortly be set up to help potential buyers see which bits of the government’s /..337 billion-worth of holdings ($527 billion at today’s rate, accounting for 40% of developable sites round Britain) might be surplus. The government, said the chief treasury secretary, Danny Alexander, “should not act as some kind of compulsive hoarder”. Japan has different reasons to revive sell-offs, such as to finance reconstruction after its devastating earthquake and tsunami in 2011. Eyes are once again turning to Japan Post, a giant postal-to-financial-services conglomerate whose oftpostponed partial sale could at last happen in 2015 and raise (Yen) 4 trillion ($40 billion) or more. Australia wants to sell financial, postal and aviation assets to offset the fall in revenues caused by the commodities slowdown. In almost all the countries of Europe, privatisation is likely “to surprise on the upside” as long as markets continue to mend, reckons Mr Megginson. Mr Christiansen expects to see three main areas of activity in coming years. First will be the resumption of partial sell-offs in industries such as telecoms, transport and utilities. Many residual stakes in partly privatised firms could be sold down further. France, for instance, still has hefty stakes in GDF SUEZ, Renault, Thales and Orange. The government of Francois Hollande may be ideologically opposed to privatisation, but it is hoping to reduce industrial stakes to raise funds for livelier sectors, such as broadband and health. The second area of growth should be in eastern Europe, where hundreds of large firms, including manufacturers, remain in state hands. Poland will sell down its stakes in listed firms to make up for an expected reduction in EU structural funds. And the third area is the reprivatisation of financial institutions rescued during the crisis. This process is under way: the largest privatisation in 2012 was the $18 billion offering of America’s residual stake in AIG, an insurance company.Which of the following statements is not true in the context of the given passage ?
....

MCQ->Choose the best way of writing the sentence.A. Any action of government to reduce the systemic risk inherent in financial markets will also reduce the risks that private operators perceive and thereby encourage excessive hedging.B. Any action by government to reduce the systemic risk inherent in financial markets will also reduce the risks that private operators perceive and thereby encourage excessive gambling.C. Any action by government to reduce the systemic risk inherent in financial markets will also reduce the risks that private operators perceive and thereby encourages excessive gambling.D. Any action of government to reduce the systemic risk inherent in financial markets will also reduce the risks that private operators perceive and thereby encourages excessive gambling.....

MCQ->S1: Metals are today being replaced by polymers in many applications. P : Above all, they are cheaper and easier to process making them a viable alternative to metals. Q : Polymers are essentially a long chains of hydrocarbon molecules. R : Today polymers as strong as metals have been developed. S : These have replaced the traditional chromium-plated metallic bumpers in cars. S6: Many Indian Institutes of science and Technology run special programmes on polymer science. The Proper sequence should be:....