Organisms can synthesize ATP by oxidative phosphorylation when they ?->(Show Answer!)

1. Organisms can synthesize ATP by oxidative phosphorylation when they

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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
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MCQ->Organisms can synthesize ATP by oxidative phosphorylation when they....

MCQ-> Read the following passage carefully and answer the questions given below it. Certain word/phrases have been printed in bold to help you locate them while answering some of the questions.The men of Suvarnanagari were very lazy. They only liked to gossip and tell each other tall tales. As soon as the sun rose, the men would tuck into hearty breakfast and then gather in groups for their daily session of gossiping. Then they would spend the rest of the day telling each other impossible stories. They came back only at lunch and dinner time. The farmlands of Suvarnanagari were very fertile. If the men had spent even a little time at fields, they would have reaped wonderful crops. But as they did nothing, all the responsibilities ended up on shoulders of the woman. They had to work hard the whole day. They cooked, cleaned, sent the children to school, worked in the fields, took the crops to the market - in short they did everything. One day the tired woman gathered and decided that the men needed to be taught a lesson. One of them suggested that they should write to the king about their problem, as he was known to be just and a kind person. So the letter was written and sent to the king. The women went back to their daily routines, hoping that the king would soon take some action. Many days passed, nothing changed, no one came, and the poor women began to lose hope. ‘After all why would the king of such a vast empire be concerned about the plight of the women of such a tiny village?’ they thought. A month passed by and it was a full moon night. The men ate their dinners and because it was so beautiful and well lit outside, they gathered again to chat and boast. That night they were trying to prove to one another that they were capable of performing the most impossible tasks. Soon a tall and handsome stranger joined them. Seeing his noble features and intelligent eyes, each one wanted to prove himself better than the others and impress to him. One said, ‘’I knew the map of this kingdom even before I was born. I ran to meet the king as soon as I was born, my mother had such trouble bringing me back home !’’ Everyone was impressed by this story. Soon another man said, ‘’So what is so great about that ? When I was a just a day old, I could ride a horse. I sat on a big horse and rode all the way to the king’s palace. He received me with lot of love and we had the most delicious meal together.’’ This was even more impressive, so everyone applauded. Now the third man said, ‘’Huh! That is nothing. I sat on an elephant when I was a week old and had lunch with the king in his palace.’’Before the admiring murmurs could die down, the fourth man said, ‘’When I was a month old, I flew like a bird and landed in the king’s garden. The king picked me up and even let me sit on his throne with him,’’ While everyone was in awe of these stories, the stranger spoke up, ‘’ Do all four of you know the king very well?’’ ‘’Of course we do! ‘’ they replied together. ‘’Our king knows and love us. In fact, he is proud to have supernatural beings like us in his kingdom,’’ one of them added. The stranger looked thoughtful. ‘’That makes my task so much easier. You see, I work in the king’s court. Some days ago the king had summoned four supermen to the city in order to repair a large hole in the city wall. As you know, we use only the largest and toughest stones for building these walls, and they could be lifted and put in place only by these supermen. The four supermen asked to be paid in gold bars and the king complied.But the night they received their fee, they disappeared from the palace. I have been wandering around ever since looking for them. The king has ordered me to find the four men and bring them back to the capital to finish the work. They will also have to return the gold bars they ran away with. It looks like the search has finally ended. I will take the four of you to the king along with the gold bars. The king will be very pleased with me and will surely reward me,’’ said the stranger. By the time the stranger finished his story, the four men realised that their lies had landed them into a huge trouble. Their faces turned ashamed and they dived at the stranger’s feet. ‘’Those were all lies. We are all just a bunch of lazy men. But if you forgive us and forget our stories, we promise to do some honest work and stop telling such lies,’’ they wailed. The stranger smiled and said, ’’Alright, I will tell the king there are no supermen in this village, just honest and hardworking men and women.’’ That night the stranger left the village. The women were sure that it was none other than the king himself.How did the men of Suvarnanagiri spend their days ?
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MCQ-> I think that it would be wrong to ask whether 50 years of India's Independence are an achievement or a failure. It would be better to see things as evolving. It's not an either-or question. My idea of the history of India is slightly contrary to the Indian idea.India is a country that, in the north, outside Rajasthan, was ravaged and intellectually destroyed to a large extent by the invasions that began in about AD 1000 by forces and religions that India had no means of understanding.The invasions are in all the schoolbooks. But I don't think that people understand that every invasion, every war, every campaign, was accompanied by slaughter, a slaughter always of the most talented people in the country. So these wars, apart from everything else led to a tremendous intellectual depletion of the country.I think that in the British period, and in the 50 years after the British period, there has been a kind of regrouping or recovery, a very slow revival of energy and intellect. This isn't an idea that goes with the vision of the grandeur of old India and all that sort of rubbish. That idea is a great simplification and it occurs because it is intellectually, philosophically easier for Indians to manage.What they cannot manage, and what they have not yet come to terms with, is that ravaging of all the north of India by various conquerors. That was ruined not by the act of nature, but by the hand of man. It is so painful that few Indians have begun to deal with it. It is much easier to deal with British imperialism. That is a familiar topic, in India and Britain. What is much less familiar is the ravaging of India before the British.What happened from AD 1000 onwards, really, is such a wound that it is almost impossible to face. Certain wounds are so bad that they can't be written about. You deal with that kind of pain by hiding from it. You retreat from reality. I do not think, for example, that the Incas of Peru or the native people of Mexico have ever got over their defeat by the Spaniards. In both places the head was cut off. I think the pre-British ravaging of India was as bad as that.In the place of knowledge of history, you have various fantasies about the village republic and the Old Glory. There is one big fantasy that Indians have always found solace in: about India having the capacity for absorbing its conquerors. This is not so. India was laid low by its conquerors.I feel the past 150 years have been years of every kind of growth. I see the British period and what has continued after that as one period. In that time, there has been a very slow intellectual recruitment. I think every Indian should make the pilgrimage to the site of the capital of the Vijayanagar empire, just to see what the invasion of India led to. They will see a totally destroyed town. Religious wars are like that. People who see that might understand what the centuries of slaughter and plunder meant. War isn't a game. When you lost that kind of war, your town was destroyed, the people who built the towns were destroyed. You are left with a headless population.That's where modern India starts from. The Vijayanagar capital was destroyed in 1565. It is only now that the surrounding region has begun to revive. A great chance has been given to India to start up again, and I feel it has started up again. The questions about whether 50 years of India since Independence have been a failure or an achievement are not the questions to ask. In fact, I think India is developing quite marvelously, people thought — even Mr Nehru thought — that development and new institutions in a place like Bihar, for instance, would immediately lead to beauty. But it doesn't happen like that. When a country as ravaged as India, with all its layers of cruelty, begins to extend justice to people lower down, it's a very messy business. It's not beautiful, it's extremely messy. And that's what you have now, all these small politicians with small reputations and small parties. But this is part of growth, this is part of development. You must remember that these people, and the people they represent, have never had rights before.When the oppressed have the power to assert themselves, they will behave badly. It will need a couple of generations of security, and knowledge of institutions, and the knowledge that you can trust institutions — it will take at least a couple of generations before people in that situation begin to behave well. People in India have known only tyranny. The very idea of liberty is a new idea. The rulers were tyrants. The tyrants were foreigners. And they were proud of being foreign. There's a story that anybody could run and pull a bell and the emperor would appear at his window and give justice. This is a child's idea of history — the slave's idea of the ruler's mercy. When the people at the bottom discover that they hold justice in their own hands, the earth moves a little. You have to expect these earth movements in India. It will be like this for a hundred years. But it is the only way. It's painful and messy and primitive and petty, but it’s better that it should begin. It has to begin. If we were to rule people according to what we think fit, that takes us back to the past when people had no voices. With self-awareness all else follows. People begin to make new demands on their leaders, their fellows, on themselves.They ask for more in everything. They have a higher idea of human possibilities. They are not content with what they did before or what their fathers did before. They want to move. That is marvellous. That is as it should be. I think that within every kind of disorder now in India there is a larger positive movement. But the future will be fairly chaotic. Politics will have to be at the level of the people now. People like Nehru were colonial — style politicians. They were to a large extent created and protected by the colonial order. They did not begin with the people. Politicians now have to begin with the people. They cannot be too far above the level of the people. They are very much part of the people. It is important that self-criticism does not stop. The mind has to work, the mind has to be active, there has to be an exercise of the mind. I think it's almost a definition of a living country that it looks at itself, analyses itself at all times. Only countries that have ceased to live can say it's all wonderful.The central thrust of the passage is that
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MCQ-> The highest priced words are ghost-written by gagmen who furnish the raw material for comedy over the air and on the screen. They have a word-lore all their own, which they practise for five to fifteen hundred dollars a week, or fifteen dollars a gag at piece rates. That's sizable rate for confounding acrimony with matrimony, or extracting attar of roses from the other.Quite apart from the dollar sign on it, gagmen's word-lore is worth a close look, if you are given to the popular American pastime of playing with words — or if you're part of the 40 per cent who make their living in the word trade. Gag writers' tricks with words point up the fact that we have two distinct levels of language: familiar, ordinary words that everybody knows; and more elaborate words that don't turn up so often, but many of which we need to know if we are to feel at home in listening and reading today.To be sure gagmen play hob with the big words, making not sense but fun of them. They keep on confusing bigotry with bigamy, illiterate with illegitimate, monotony with monogamy, osculation with oscillation. They trade on the fact that for many of their listeners, these fancy terms linger in a twilight zone of meaning. It’s their deliberate intent to make everybody feel cozy at hearing big words, jumbled up or smacked down. After all, such words loom up over-size in ordinary talk, so no wonder they get the bulldozer treatment from the gagmen.Their wrecking technique incidentally reveals our language as full of tricky words, some with 19 different meanings, others which sound alike but differ in sense. To ring good punning changes, gag writers have to know their way around in the language. They don't get paid for ignorance, only for simulating it.Their trade is a hard one, and they regard it as serious business. They never laugh at each other's jokes; rarely at their own. Like comediennes, they are usually melancholy men in private life.Fertile invention and ingenious fancy are required to clean up ‘blue’ burlesque gags for radio use. These shady gags are theoretically taboo on the air. However, a gag writer who can leave a faint trace of bluing when he launders the joke is all the more admired — and more highly paid. A gag that keeps the blue tinge is called a ‘double intender’, gag-land jargon for double entendre. The double meaning makes the joke funny at two levels. Children and other innocents hearing the crack for the first time take it literally, laughing at the surface humour; listeners who remember the original as they heard it in vaudeville or burlesque, laugh at the artfulness with which the blue tinge is disguised.Another name for a double meaning of this sort is ‘insinuendo’. This is a portmanteau word or ‘combo’, as the gagmen would label it, thus abbreviating combination. By telescoping insinuation and innuendo, they get insinuendo, on the principle of blend words brought into vogue by Lewis Caroll. ‘Shock logic’ is another favourite with gag writers. Supposedly a speciality of women comediennes, it is illogical logic more easily illustrated than defined. A high school girl has to turn down a boy's proposal, she writes:Dear Jerry, I'm sorry, but I can't get engaged to you. My mother thinks I am too young to be engaged and besides, I'm already engaged to another boy. Yours regretfully. Guess who.Gag writers' lingo is consistently funnier than their gags. It should interest the slang-fancier. And like much vivid jargon developed in specialised trades and sports, a few of the terms are making their way into general use. Gimmick, for instance, in the sense either of a trick devised or the point of a joke, is creeping into the vocabulary of columnists and feature writers.Even apart from the trade lingo, gagmen's manoeuvres are of real concern to anyone who follows words with a fully awakened interest. For the very fact that gag writers often use a long and unusual word as the hinge of a joke, or as a peg for situation comedy, tells us something quite significant: they are well aware of the limitations of the average vocabulary and are quite willing to cash in on its shortcomings.When Fred Allens' joke-smiths work out a fishing routine, they have Allen referring to the bait in his most arch and solemn tones: "I presume you mean the legless invertebrate." This is the old minstrel trick, using a long fancy term, instead of calling a worm a worm. Chico Marx can stretch a pun over 500 feet of film, making it funnier all the time, as he did when he rendered, "Why a duck?"And even the high-brow radio writers have taken advantage of gagmen's technique. You might never expect to hear on the air such words as lepidopterist and entymologist. Both occur in a very famous radio play by Norman Corvine, ‘My client Curly’, about an unusual caterpillar which would dance to the tune ‘yes, sir, she's my baby’ but remained inert to all other music. The dancing caterpillar was given a real New York buildup, which involved calling in the experts on butterflies and insects which travel under the learned names above. Corvine made mild fun of the fancy professional titles, at the same time explaining them unobtrusively.There are many similar occasions where any one working with words can turn gagmen's trade secrets to account. Just what words do they think outside the familiar range? How do they pick the words that they ‘kick around’? It is not hard to find out.According to the writer, a larger part of the American population
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