1. DNA segments capable of moving from one place in the genome to another is known as





Write Comment

Type in
(Press Ctrl+g to toggle between English and the chosen language)

Comments

Tags
Show Similar Question And Answers
QA->.... is the condition of gravitational balance between the crustal segments at different thickness?....
QA->Who was the first director of Human Genome Project (HGP) ?....
QA->Human Genome Project (HGP) HGP was launched in ?....
QA->Headquarters of National Plant-Genome Research Centre ?....
QA->Which vegetable"s genome was sequenced completely in 2012?....
MCQ->DNA segments capable of moving from one place in the genome to another is known as....
MCQ->Different DNA polymerases play distinct roles in DNA replication and repair in both prokaryotic and eukaryotic cells. All known DNA polymerases synthesize DNA only in the __________ by the addition of dNTPs to a performed primer strand of DNA.....
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-> The Union Government’s present position vis-a-vis the upcoming United Nations conference on racial and related discrimination world-wide seems to be the following: discuss race please, not caste; caste is our very own and not at all as bad as you think. The gross hypocrisy of that position has been lucidly underscored by Kancha Ilaiah. Explicitly, the world community is to be cheated out of considering the matter on the technicality that caste is not, as a concept, tantamount to a racial category. Internally, however, allowing the issue to be put on agenda at the said conference would, we are patriotically admonished, damage the country’s image. Somehow, India’s virtual beliefs elbow out concrete actualities. Inverted representations, as we know, have often been deployed in human histories as balm for the forsaken — religion being the most persistent of such inversions. Yet, we would humbly submit that if globalising our markets is thought as good for the ‘national’ pocket, globalising our social inequities might not be so bad for the mass of our people. After all, racism was as uniquely institutionalised in South Africa as caste discrimination has been within our society; why then can’t we permit the world community to express itself on the latter with a fraction of the zeal with which, through the years, we pronounced on the former?As to the technicality about whether or not caste is admissible into an agenda about race (that the conference is also about ‘related discriminations’ tends to be forgotten), a reputed sociologist has recently argued that where race is a ‘biological’ category caste is a ‘social’ one. Having earlier fiercely opposed implementation of the Mandal Commission Report, the said sociologist is at least to be complemented now for admitting, however tangentially, that caste discrimination is a reality, although, in his view, incompatible with racial discrimination. One would like quickly to offer the hypothesis that biology, in important ways that affect the lives of many millions, is in itself perhaps a social construction. But let us look at the matter in another way.If it is agreed — as per the position today at which anthropological and allied scientific determinations rest — that the entire race of homo sapiens derived from an originary black African female (called ‘Eve’), then one is hard put to understand how, one some subsequent ground, ontological distinctions are to be drawn either between races or castes. Let us also underline the distinction between the supposition that we are all god’s children and the rather more substantiated argument about our descent from ‘Eve’, lest both positions are thought to be equally diversionary. It then stands to reason that all subsequent distinctions are, in modern parlance, ‘constructed’ ones, and like all ideological constructions, attributable to changing equations between knowledge and power among human communities through contested histories here, there, and elsewhere.This line of thought receives, thankfully, extremely consequential buttress from the findings of the Human Genome project. Contrary to earlier (chiefly 19th-century colonial) persuasions on the subject of race, as well as, one might add, the somewhat infamous Jensen offerings in the 20th century from America, those finding deny genetic difference between ‘races’. If anything, they suggest that environmental factors impinge on gene-function, as a dialectic seems to unfold between nature and culture. It would thus seem that ‘biology’ as the constitution of pigmentation enters the picture first only as a part of that dialectic. Taken together, the originary mother stipulation and the Genome findings ought indeed to furnish ground for human equality across the board, as well as yield policy initiatives towards equitable material dispensations aimed at building a global order where, in Hegel’s stirring formulation, only the rational constitutes the right. Such, sadly, is not the case as everyday fresh arbitrary grounds for discrimination are constructed in the interests of sectional dominance.When the author writes ‘globalising our social inequities’, the reference is to
 ....
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 ?
 ....
Terms And Service:We do not guarantee the accuracy of available data ..We Provide Information On Public Data.. Please consult an expert before using this data for commercial or personal use
DMCA.com Protection Status Powered By:Omega Web Solutions
© 2002-2017 Omega Education PVT LTD...Privacy | Terms And Conditions