The cell walls of Gram positive bacteria contain two modified sugar, viz. N- acetylgucosamine (NAG) and N- acetylmuramic acid (NAM). They are covalently linked by ?->(Show Answer!)

1. The cell walls of Gram positive bacteria contain two modified sugar, viz. N- acetylgucosamine (NAG) and N- acetylmuramic acid (NAM). They are covalently linked by

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MCQ->The cell walls of Gram positive bacteria contain two modified sugar, viz. N- acetylgucosamine (NAG) and N- acetylmuramic acid (NAM). They are covalently linked by....

MCQ-> "All raw sugar comes to us this way. You see, it is about the color of maple or brown sugar, but it is not nearly so pure, for it has a great deal of dirt mixed with it when we first get it." "Where does it come from?" inquired Bob."Largely from the plantations of Cuba and Porto Rico. Toward the end of the year we also get raw sugar from Java, and by the time this is refined and ready for the market the new crop from the West Indies comes along. In addition to this we get consignments from the Philippine Islands, the Hawaiian Islands, South America, Formosa, and Egypt. I suppose it is quite unnecessary to tell you young men anything of how the cane is grown; of course you know all that.""I don't believe we do, except in a general way," Bob admitted honestly. "I am ashamed to be so green about a thing at which Dad has been working for years. I don't know why I never asked about it before. I guess I never was interested. I simply took it for granted.""That's the way with most of us," was the superintendent's kindly answer. "We accept many things in the world without actually knowing much about them, and it is not until something brings our ignorance before us that we take the pains to focus our attention and learn about them. So do not be ashamed that you do not know about sugar raising; I didn't when I was your age. Suppose, then, I give you a little idea of what happens before this raw sugar can come to us.""I wish you would," exclaimed both boys in a breath."Probably in your school geographies you have seen pictures of sugar-cane and know that it is a tall perennial not unlike our Indian corn in appearance; it has broad, flat leaves that sometimes measure as many as three feet in length, and often the stalk itself is twenty feet high. This stalk is jointed like a bamboo pole, the joints being about three inches apart near the roots and increasing in distance the higher one gets from the ground.""How do they plant it?" Bob asked."It can be planted from seed, but this method takes much time and patience; the usual way is to plant it from cuttings, or slips. The first growth from these cuttings is called plant cane; after these are taken off the roots send out ratoons or shoots from which the crop of one or two years, and sometimes longer, is taken. If the soil is not rich and moist replanting is more frequently necessary and in places like Louisiana, where there is annual frost, planting must be done each year. When the cane is ripe it is cut and brought from the field to a central sugar mill, where heavy iron rollers crush from it all the juice. This liquid drips through into troughs from which it is carried to evaporators where the water portion of the sap is eliminated and the juice left; you would be surprised if you were to see this liquid. It looks like nothing so much as the soapy, bluish gray dish-water that is left in the pan after the dishes have been washed.""A tempting picture!" Van exclaimed."I know it. Sugar isn't very attractive during its process of preparation," agreed Mr. Hennessey. "The sweet liquid left after the water has been extracted is then poured into vacuum pans to be boiled until the crystals form in it, after which it is put into whirling machines, called centrifugal machines that separate the dry sugar from the syrup with which it is mixed. This syrup is later boiled into molasses. The sugar is then dried and packed in these burlap sacks such as you see here, or in hogsheads, and shipped to refineries to be cleansed and whitened.""Isn't any of the sugar refined in the places where it grows?" queried Bob."Practically none. Large refining plants are too expensive to be erected everywhere; it therefore seems better that they should be built in our large cities, where the shipping facilities are good not only for receiving sugar in its raw state but for distributing it after it has been refined and is ready for sale. Here, too, machinery can more easily be bought and the business handled with less difficulty." Which one of the following is not a essential condition for setting up sugar refining plants?
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MCQ-> The controversy over genetically modified food continues unabated in the West. Genetic modification (GM) is the science by which the genetic material of a plant is altered, perhaps to make it more resistant to pests or killer weeds, or to enhance its nutritional value. Many food biotechnologists claim that GM will be a major contribution of science to mankind in the 21st century. On the other hand, large numbers of opponents, mainly in Europe, claim that the benefits of GM are a myth propagated by multinational corporations to increase their profits, that they pose a health hazard, and have therefore called for government to ban the sale of genetically-modified food.The anti-GM campaign has been quite effective in Europe, with several European Union member countries imposing a virtual ban for five years over genetically-modified food imports. Since the genetically-modified food industry is particularly strong in the United States of America, the controversy also constitutes another chapter in the US-Europe skirmishes which have become particularly acerbic after the US invasion of Iraq.To a large extent, the GM controversy has been ignored in the Indian media, although Indian biotechnologists have been quite active in GM research. Several groups of Indian biotechnologists have been working on various issues connected with crops grown in India. One concrete achievement which has recently figured in the news is that of a team led by the former vice-chancellor of Jawaharlal Nehru university, Asis Datta — it has successfully added an extra gene to potatoes to enhance the protein content of the tuber by at least 30 percent. It is quite likely that the GM controversy will soon hit the headlines in India since a spokesperson of the Indian Central government has recently announced that the government may use the protato in its midday meal programme for schools as early as next year.Why should “scientific progress”, with huge potential benefits to the poor and malnourished, be so controversial? The anti-GM lobby contends that pernicious propaganda has vastly exaggerated the benefits of GM and completely evaded the costs which will have to be incurred if the genetically-modified food industry is allowed to grow unchecked. In particular, they allude to different types of costs.This group contends that the most important potential cost is that the widespread distribution and growth of genetically-modified food will enable the corporate world (alias the multinational corporations – MNCs) to completely capture the food chain. A “small” group of biotech companies will patent the transferred genes as well as the technology associated with them. They will then buy up the competing seed merchants and seed-breeding centers, thereby controlling the production of food at every possible level. Independent farmers, big and small, will be completely wiped out of the food industry. At best, they will be reduced to the status of being subcontractors.This line of argument goes on to claim that the control of the food chain will be disastrous for the poor since the MNCs, guided by the profit motive, will only focus on the high-value food items demanded by the affluent. Thus, in the long run, the production of basic staples which constitute the food basket of the poor will taper off. However, this vastly overestimates the power of the MNCs. Even if the research promoted by them does focus on the high-value food items, much of biotechnology research is also funded by governments in both developing and developed countries. Indeed, the protato is a by-product of this type of research. If the protato passes the field trials, there is no reason to believe that it cannot be marketed in the global potato market. And this type of success story can be repeated with other basic food items.The second type of cost associated with the genetically modified food industry is environmental damage. The most common type of “genetic engineering” involved gene modification in plants designed to make them resistant to applications of weed-killers. This then enables farmers to use massive dosages of weedkillers so as to destroy or wipe out all competing varieties of plants in their field. However, some weeds through genetically-modified pollen contamination may acquire resistance to a variety of weed-killers. The only way to destroy these weeds is through the use of ever-stronger herbicides which are poisonous and linger on in the environment.The author doubts the anti-GM lobby’s contention that MNC control of the food chain will be disastrous for the poor because
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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-> 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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