In absence of ribosome in cell which function does not takes place? ?->(Show Answer!)

1. In absence of ribosome in cell which function does not takes place?

Answer: Protein synthesis

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MCQ-> The membrane-bound nucleus is the most prominent feature of the eukaryotic cell. Schleiden and Schwann, when setting forth the cell doctrine in the 1830s, considered that it had a central role in growth and development. Their belief has been fully supported even though they had only vague notions as to what that role might be, and how the role was to be expressed in some cellular action. The membraneless nuclear area of the prokaryotic cell, with its tangle of fine threads, is now known to play a similar role.Some cells, like the sieve tubes of vascular plants and the red blood cells of mammals, do not possess nuclei during the greater part of their existence, although they had nuclei when in a less differentiated state. Such cells can no longer divide and their life span is limited Other cells are regularly multinucleate. Some, like the cells of striated muscles or the latex vessels of higher plants, become so through cell fusion. Some, like the unicellular protozoan paramecium, are normally binucleate, one of the nuclei serving as a source of hereditary information for the next generation, the other governing the day-to-day metabolic activities of the cell. Still other organisms, such as some fungi, are multinucleate because cross walls, dividing the mycelium into specific cells, are absent or irregularly present. The uninucleate situation, however, is typical for the vast majority of cells, and it would appear that this is the most efficient and most economical manner of partitioning living substance into manageable units. This point of view is given credence not only by the prevalence of uninucleate cells, but because for each kind of cell there is a ratio maintained between the volume of the nucleus and that of the cytoplasm. If we think of the nucleus as the control centre of the cell, this would suggest that for a given kind of cell performing a given kind of work, one nucleus can ‘take care of’ a specific volume of cytoplasm and keep it in functioning order. In terms of material and energy, this must mean providing the kind of information needed to keep flow of materials and energy moving at the correct rate and in the proper channels. With the multitude of enzymes in the cell, materials and energy can of course be channelled in a multitude of ways; it is the function of some information molecules to make channels of use more preferred than others at any given time. How this regulatory control is exercised is not entirely clear.The nucleus is generally a rounded body. In plant cells, however, where the centre of the cell is often occupied by a large vacuole, the nucleus may be pushed against the cell wall, causing it to assume a lens shape. In some white blood cells, such as polymorphonucleated leukocytes, and in cells of the spinning gland of some insects and spiders, the nucleus is very much lobed The reason for this is not clear, but it may relate to the fact that for a given volume of nucleus, a lobate form provides a much greater surface area for nuclear-cytoplasmic exchanges, possibly affecting both the rate and the amount of metabolic reactions. The nucleus, whatever its shape, is segregated from the cytoplasm by a double membrane, the nuclear envelope, with the two membranes separated from each other by a perinuclear space of varying width. The envelope is absent only during the time of cell division, and then just for a brief period The outer membrane is often continuous with the membranes of the endoplasmic reticulum, a possible retention of an earlier relationship, since the envelope, at least in part, is formed at the end cell division by coalescing fragments of the endoplasmic reticulum. The cytoplasmic side of the nucleus is frequently coated with ribosomes, another fact that stresses the similarity and relation of the nuclear envelope to the endoplasmic reticulum. The inner membrane seems to posses a crystalline layer where it abuts the nucleoplasm, but its function remains to be determined.Everything that passes between the cytoplasm and the nucleus in the eukaryotic cell must transverse the nuclear envelope. This includes some fairly large molecules as well as bodies such as ribosomes, which measure about 25 mm in diameter. Some passageway is, therefore, obviously necessary since there is no indication of dissolution of the nuclear envelope in order to make such movement possible. The nuclear pores appear to be reasonable candidates for such passageways. In plant cells these are irregularly, rather sparsely distributed over the surface of the nucleus, but in the amphibian oocyte, for example, the pores are numerous, regularly arranged, and octagonal and are formed by the fusion of the outer and inner membrane.Which of the following kinds of cells never have a nuclei?
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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-> Study the following information carefully• and answer the questions given below : Seven friends, namely, M, N, 0, P, Q, R and S, have one essay competition each on seven different days of the same week from Monday to Sunday, but not necessarily in the same order. Each one of them studies in different classes, viz, First, Second, Third, Fourth. Fifth. Sixth and Seventh, but not necessarily in the same order. The one who studies in the First Standard has an essay competition on Saturday. S studies in the Second Standard and has an esay competion on Wednesday. N has the essay competition immediately before Q. N does not have the essay competition on any day after that of S. The one who studies in the Seventh Standard does not have an essay competition on any of the days on or before Friday. The one who studies in the Third Standard has the essay competition immediately after 0. Q does not study in the Fifth Standard. The one who studies in the Sixth standard does not have the essay competition immediately before or after S. R does not have the essay competition on Sunday and does not study in the Third Standard. P does not have the essay competition on any of the days before that of M.In which of the following standards does R study ?
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MCQ-> Read the following passage and solve the questions based on it.In an. Engineering College, five students from five different cities were elected as Secretaries by the students to perform different student activities. Each student studies in a different branch of engineering. Additionally, the following information is provided:(i) Abhishek does not stay in the Aravalli hostel where the student from Nagpur stays. (ii) The student, whose name is not Abhishek and does not study in Metallurgy, stays in Satpura hostel. He is the only student among the five to stay at Satpura hostel (iii) Hardeep neither belongs to Jodhpur, nor does he study Mechanical Engineering. (iv) The student-in-charge of Cultural activity stays in the Aravalli hostel where Civil Engineering student does not stay. (v) Sanjoy and thistudent, who studies Metallurgy, both stay in the same hostel. (vi) The student who belongs to Allahabad does not stay with the student-in-charge of the Sports activity staying at Aravalli hostel. (vii) Sanjoy is not the student-in-charge of the Cultural activity. (viii) Ravi, the student-in-charge of Mess activity, stays at Satpura hostel. (ix) The student from Patna and the student, who studies Mechanical Engineering, both stay at Aravalli hostel. They are the only two among the five students to stay at this hostel. (x) The student, who stays at Satpura hostel, studies Computer Science. (xi) Hemant, who does not belong to Kochi, studies Chemical Engineering. He is not the General Secretary of the Student Body. (xii) Sanjoy does not belong to Allahabad. (xiii) The student from Kochi and the student-in-charge of Placement activity, both stay at the Vindhya hostel.Which of the following statement(s) is (are) incorrect? I. The Chemical Engineering student and the student-in-charge of Cultural activity, both stay in the same hostel. II. The student in-charge of Placement activity is studying Metallurgy. III. The student who belongs to Nagpur is the student-in-charge of Sports activity. IV. Ravi belongs to Jodhpur....

MCQ-> Read the following passage carefully and answer the question given below it. Certain words have been printed in bold to help you locate them while answering some of the questions.Agriculture has always been celebrated as the primary sector in India. Thanks to the Green Revolution, India is now self-sufficient in food production. Indian agriculture has been making technological advancement as well. Does that mean everything is looking bright for Indian agriculture ? A superficial analysis of the above points would tempt one to say yes, but the truth is far from it. The reality is that Indian farmers have to face extreme poverty and financial crisis, which is driving them to suicides. What are the grave adversities that drive the farmers to commit suicide, at a time when Indian economy is supposed to be gearing up to take on the world ?Indian agriculture is predominantly dependent on nature. Irrigation facilities that are currently available, do not cover the entire cultivable land. If the farmers are at the mercy of monsoons for timely water for their crops, they are at the mercy of the government for alternative irrigation facilities. Any failure of nature, directly affects the fortunes of the farmers. Secondly, Indian agriculture is largely an unorganized sector, there is no systematic planning in cultivation, farmers work on lands of uneconomical sizes, institutional finances are not available and minimum purchase prices of the government do not in reality reach the poorest farmer. Added to this, the cost of agricultural inputs have been steadily rising over the years, farmers’ margins of profits have been narrowing because the price rise in inputs is not complemented by an increase in the purchase price of the agricultural produce. Even today, in several parts of the country, agriculture is a seasonal occupation. In many districts, farmers get only one crop per year and for the remaining part of the year, they find it difficult to make both ends meet.The farmers normally resort to borrowing from money lenders, in the absence of institutionalized finance. Where institutional finance is available, the ordinary farmer does not have a chance of availing it because of the “procedures” involved in disbursing the finance. This calls for removing the elaborate formalities for obtaining the loans. The institutional finance, where available is mostly availed by the medium or large land owners, the small farmers do not even have the awareness of the existence of such facilities. The money lender is the only source of finance to the farmers. Should the crops fail, the farmers fall into a debt trap and crop failures piled up over the years give them no other option than ending their lives.Another disturbing trend has been observed where farmers commit suicide or deliberately kill a family member in order to avail relief and benefits announced by the government to support the families of those who have committed suicide so that their families could at least benefit from the Government’s relief programmes. What then needs to be done to prevent this sad state of affairs ? There cannot be one single solution to end the woes of farmers.Temporary measures through monetary relief would not be the solution. The governmental efforts should be targeted at improving the entire structure of the small wherein the relief is not given on a drought to drought basis, rather they are taught to overcome their difficulties through their own skills and capabilities. Social responsibility also goes a long way to help the farmers. General public, NGOs, Corporate and other organizations too can play a part in helping farmers by adopting drought affected villages and families and helping them to rehabilitate.The nation has to realize that farmers’ suicides are not minor issues happening in remote parts of a few states, it is a reflection of the true state of the basis of our economy.What does the author mean by “procedures” when he says that ‘farmers do not get a chance of availing institutional finance because of procedures involved in it’ ?
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