Membalas kebaikan dengan kebaikan adalah wajar/baik
Membalas kebaikan dengan kejahatan adalah zalim
Membalas kejahatan dengan kebaikan adalah mulia
Ingatlah dan kenanglah dua perkara...
Kebaikan orang lain terhadap kita dan kejahatan kita terhadap orang lain
Lupakanlah dua perkara...
Kebaikan kita terhadap orang lain dan kejahatan orang lain terhadap kita
Apabila kita mengingat dan mengenang kebaikan orang lain terhadap kita, kita akan jadi orang yang mengenang budi
Apabila kita mengingati kejahatan kita terhadap orang lain, kita tidak akan melakukan kejahatan lagi
Jika kita melupakan kebaikan kita terhadap orang lain, kita tidak akan mengungkit kebaikan yang kita telah lakukan
Jika kita melupakan kejahatan orang lain terhadap kita, kita adalah orang yang pemaaf
Pengajaran
Kepada pelajar-pelajar... jadilah orang yang baik dan tahu mengenang budi, janganlah jadi orang yang zalim terhadap guru anda.
Sesungguhnya guru adalah orang yang mulia kerana sentiasa berbuat baik kepada anda semua, walaupun kadang-kadang anda membalasnya dengan kejahatan.
Friday, August 15, 2008
Friday, August 8, 2008
GM FOOD
Genetically modified food
Genetically modified (GM) foods, more accurately called genetically engineered foods, are foods that have had their DNA altered through genetic engineering. Unlike conventional genetic modification that is carried out through conventional breeding and that have been consumed for thousands of years, GE foods were first put on the market in the early 1990s. The most common modified foods are derived from plants: soybean, corn, canola, and cotton seed oil.
Controversies surrounding GM foods and crops commonly focus on human and environmental safety, labeling and consumer choice, intellectual property rights, ethics, food security, poverty reduction, and environmental conservation.
The first commercially grown genetically modified whole food crop was the tomato, which was made more resistant to rotting by Californian company Calgene. Calgene was allowed to release the tomatoes into the market in 1994 without any special labeling. It was welcomed by consumers who purchased the fruit at two to five times the price of regular tomatoes. However, production problems and competition from a conventionally bred, longer shelf-life variety prevented the product from becoming profitable. A variant of the Flavr Savr was used by Zeneca to produce tomato paste which was sold in Europe during the summer of 1996. The labeling and pricing were designed as a marketing experiment, which proved, at the time, that European consumers would accept genetically engineered foods.
The attitude towards GM foods would be drastically changed after outbreaks of Mad Cow Disease weakened consumer trust in government regulators, and protesters rallied against the introduction of Monsanto's "Roundup-Ready" soybeans.[citation needed] The next GM crops included insect-resistant cotton and herbicide-tolerant soybeans both of which were commercially released in 1996. GM crops have been widely adopted in the United States. They have also been extensively planted in several other countries (Argentina, Brazil, South Africa, India, and China) where the agriculture is a major part of the total economy. Other GM crops include insect-resistant maize and herbicide-tolerant maize, cotton, and rapeseed varieties.
GM Foods currently
Currently, there are a of number of foods of which a genetically modified version exists.
Food
Properties of the genetically modified variety
Trade name and the company which produced initial version
Specific genetic modification
Percent the genetically modified version occupies of the given foods' agriculture in USA
Percent this GMF takes up of agriculture compared to its non-GMF version, globally
Soybeans
Resistant to herbicides
Roundup Ready, Monsanto
Herbicide resistant gene taken from bacteria inserted into soy bean
TBA
TBA
Corn
Resistance to certain pesticides (tolerating crop spray - this way a farmer can use amounts of pesticides which would normally kill the plant, without harming it)
TBA
New gene added/transferred into plant genome
TBA
TBA
Cotton
Pest-resistant cotton
TBA
New gene added/transferred into plant genome
TBA
TBA
Tomatoes
Variety that does not rot (degrade) as fast - the genetically modified tomatoes do not produce a substance that normally causes tomatoes to rot.
E.g. FlavrSavr
First genetically modified tomatoes contained genes that made them resistant to antibiotics. After concern from doctors and the medical community, tomatoes are now genetically modified in an alternative way
TBA
TBA
Potatoes
TBA
TBA
Rapeseed (Canola)
Resistance to certain pesticides (tolerating crop spray)
TBA
New gene added/transferred into plant genome
TBA
TBA
Sugar cane
Resistance to certain pesticides (tolerating crop spray)
TBA
New gene added/transferred into plant genome
TBA
TBA
Sweet corn
Produces its own insecticide (a toxin to insects, so insect attacks are less likely)
Bt corn
Insect-killing gene added to the plant. The gene comes from the bacteria Bacillus thuringiensis.
TBA
TBA
Rice
Genetically modified to contain high amounts of Vitamin A (beta-carotene)
"Golden rice"
Three new genes implanted: two from daffodils and the third from a bacterium
TBA
TBA
Abundance of GM crops
Between 1995 and 2005, the total surface area of land cultivated with GMOs had increased by a factor of 50, from 17,000 km² (4.2 million acres) to 900,000 km² (222 million acres), of which 55 percent were Brazil.
Although most GM crops are grown in North America, in recent years there has been rapid growth in the area sown in developing countries. For instance in 2005 the largest increase in crop area planted to GM crops (soybeans) was in Brazil (94,000 km² in 2005 versus 50,000 km² in 2004.)There has also been rapid and continuing expansion of GM cotton varieties in India since 2002. (Cotton is a major source of vegetable cooking oil and animal feed.) It is predicted that in 2006/7 32,000 km² of GM cotton will be harvested in India (up more than 100 percent from the previous season). Indian national average cotton yields of GM cotton were seven times lower in 2002, because the parental cotton plant used in the genetic engineered was not well suited to the climate of India and failed. The publicity given to transgenic trait Bt insect resistance has encouraged the adoption of better performing hybrid cotton varieties, and the Bt trait has substantially reduced losses to insect predation. Economic and environmental benefits of GM cotton in India to the individual farmer have been documented.
In 2003, countries that grew 99 percent of the global transgenic crops were the United States (63 percent), Argentina (21 percent), Canada (6 percent), Brazil (4 percent), China (4 percent), and South Africa (1 percent).The Grocery Manufacturers of America estimate that 75 percent of all processed foods in the U.S. contain a GM ingredient . In particular, Bt corn, which produces the pesticide within the plant itself is widely grown, as are soybeans genetically designed to tolerate glyphosate herbicides. These constitute "input-traits" are aimed to financially benefit the producers, have indirect environmental benefits and marginal cost benefits to consumers.
In the US, by 2006 89% of the planted area of soybeans, 83 percent of cotton, and 61 percent maize was genetically modified varieties. Genetically modified soybeans carried herbicide tolerant traits only, but maize and cotton carried both herbicide tolerance and insect protection traits (the latter largely the Bacillus thuringiensis Bt insecticidal protein). In the period 2002 to 2006, there were significant increases in the area planted to Bt protected cotton and maize, and herbicide tolerant maize also increased in sown area.
However, several studies have found that genetically modified varieties of plants do not produce higher yields than normal plants.
Coexistence and traceability
In many parts of the world such as the European Union, Japan, Malaysia and Australia consumers demand labelling so they can exercise choice between foods that have genetically modified, conventional or more natural organic origins.This requires a labelling system as well as the reliable separation of GM and non-GM organisms at production level and throughout the whole processing chain.
Research has demonstrated, that coexistence of GM crops can be realised by several agricultural measures, such as isolation distances or biological containment strategies.
For traceability, the OECD has introduced a "unique identifier" which is given to any GMO when it is approved. This unique identifier must be forwarded at every stage of processing.
Many countries have established labelling regulations and guidelines on coexistence and traceability. Research projects such as Co-Extra, SIGMEA and Transcontainer are aimed at investigating improved methods for ensuring coexistence and providing stakeholders the tools required for the implementation of coexistence and traceability.
The GM food controversy is a dispute over the advantages and disadvantages of genetically modified food crops. See Genetically modified food controversies.init
Debate around the world
Some argue that there is more than enough food in the world (morons) and that the hunger crisis is caused by problems in food distribution and politics, not production, so people should not be offered food that may carry some degree of risk.
Others oppose genetic engineering on the grounds that genetic modifications might have unforeseen consequences, both in the initially modified organisms and their environments. For example, certain strains of maize have been developed that are toxic to plant eating insects (see Bt corn). It has been alleged those strains cross-pollinated with other varieties of wild and domestic maize and passed on these genes with a putative impact on Maize biodiversity.Subsequent to the publication of these results, several scientists pointed out that the conclusions were based on experiments with design flaws. It is well known that the results from polymerase chain reaction (PCR) methods of analysing DNA can often be confounded by sample contamination and experimental artifacts. Appropriate controls can be included in experiments to eliminate these as a possible explanation of the results - however these controls were not included in the methods used by Quist and Chapela. After this criticism Nature, the scientific journal where this data was originally published concluded that "the evidence available is not sufficient to justify the publication of the original paper". More recent attempts to replicate the original studies have concluded that genetically modified corn is absent from southern Mexico in 2003 and 2004 . Also in dispute is the impact on biodiversity of the introgression of transgenes into wild populations. Unless a transgene offers a massive selective advantage in a wild population, a transgene that enters such a population will be maintained at a low gene frequency. In such situations it can be argued that such an introgression actually increases biodiversity rather than lowers it.
Activists opposed to genetic engineering say that with current recombinant technology there is no way to ensure that genetically modified organisms will remain under control, and the use of this technology outside secure laboratory environments carries potentially unacceptable risks to both farmed and wild ecosystems.
Potential impact on biodiversity may occur if herbicide-tolerant crops are sprayed with herbicide to the extent that no wild plants ('weeds') are able to survive. Plants toxic to insects may mean insect-free crops. This could result in declines in other wildlife (e.g. birds) which feed on weed seeds and/or insects for food resources. The recent (2003) farm scale studies in the UK found this to be the case with GM sugar beet and GM rapeseed, but not with GM maize (though in the last instance, the non-GM comparison maize crop had also been treated with environmentally-damaging pesticides subsequently (2004) withdrawn from use in the EU).
Although some scientists have claimed that selective breeding is a form of genetic engineering, (e.g., maize was modified from teosinte, dogs have evolved with human intervention over the course of tens of thousands of years from wolves), others assert that modern transgenesis-based genetic engineering is capable of delivering changes faster than, and sometimes of different types from, traditional breeding methods.
Proponents of current genetic techniques as applied to food plants cite the benefits that the technology can have, for example, in the harsh agricultural conditions of Africa. They say that with modifications, existing crops would be able to thrive under the relatively hostile conditions providing much needed food to their people. Proponents also cite golden rice and golden rice 2, genetically engineered rice varieties (still under development) that contain elevated vitamin A levels. There is hope that this rice may alleviate vitamin A deficiency that contributes to the death of millions and permanent blindness of 500,000 annually. Although GM crops have the potential to be a crucial element in the solution for global hunger, one must not overlook the daunting fact that GM crops are not fecund. Farmers must buy GM seeds every year which makes them depended on distributors that charge more for GM seeds than regular seeds. Also seed distribution can be very difficult for countries with poor infrastructure, usually the countries that need them the most.
Proponents say that genetically-engineered crops are not significantly different from those modified by nature or humans in the past, and are as safe or even safer than such methods. There is gene transfer between unicellular eukaryotes and prokaryotes. There have been no known genetic catastrophes as a result of this. They argue that animal husbandry, Food Irradiation and crop breeding are also forms of genetic engineering that use artificial selection instead of modern genetic modification techniques. It is politics, they argue, not economics or science, that causes their work to be closely investigated, and for different standards to apply to it than those applied to other forms of agricultural technology.
Proponents also note that species or genetic barriers have been crossed in nature in the past. An oft-cited example is today's modern red wheat variety, which is the result of two natural crossings made long ago. It is made up of three groups of seven chromosomes. Each of those three groups came from a different wild wheat grass. First, a cross between two of the grasses occurred, creating the durum wheats, which were the commercial grains of the first civilizations up through the Roman Republic. Then a cross occurred between that 14-chromosome durum wheat and another wild grass to create what became modern red wheat at the time of the Roman Empire.
Future developments
Future envisaged applications of GMOs are diverse and include drugs in food, bananas that produce human vaccines against infectious diseases such as Hepatitis B, metabolically engineered fish that mature more quickly, fruit and nut trees that yield years earlier, and plants that produce new plastics with unique properties. While their practicality or efficacy in commercial production has yet to be fully tested, the next decade may see exponential increases in GM product development as researchers gain increasing access to genomic resources that are applicable to organisms beyond the scope of individual projects. Safety testing of these products will also at the same time be necessary to ensure that the perceived benefits will indeed outweigh the perceived and hidden costs of development. Plant scientists, backed by results of modern comprehensive profiling of crop composition, point out that crops modified using GM techniques are less likely to have unintended changes than are conventionally bred crops.
Genetically modified (GM) foods, more accurately called genetically engineered foods, are foods that have had their DNA altered through genetic engineering. Unlike conventional genetic modification that is carried out through conventional breeding and that have been consumed for thousands of years, GE foods were first put on the market in the early 1990s. The most common modified foods are derived from plants: soybean, corn, canola, and cotton seed oil.
Controversies surrounding GM foods and crops commonly focus on human and environmental safety, labeling and consumer choice, intellectual property rights, ethics, food security, poverty reduction, and environmental conservation.
The first commercially grown genetically modified whole food crop was the tomato, which was made more resistant to rotting by Californian company Calgene. Calgene was allowed to release the tomatoes into the market in 1994 without any special labeling. It was welcomed by consumers who purchased the fruit at two to five times the price of regular tomatoes. However, production problems and competition from a conventionally bred, longer shelf-life variety prevented the product from becoming profitable. A variant of the Flavr Savr was used by Zeneca to produce tomato paste which was sold in Europe during the summer of 1996. The labeling and pricing were designed as a marketing experiment, which proved, at the time, that European consumers would accept genetically engineered foods.
The attitude towards GM foods would be drastically changed after outbreaks of Mad Cow Disease weakened consumer trust in government regulators, and protesters rallied against the introduction of Monsanto's "Roundup-Ready" soybeans.[citation needed] The next GM crops included insect-resistant cotton and herbicide-tolerant soybeans both of which were commercially released in 1996. GM crops have been widely adopted in the United States. They have also been extensively planted in several other countries (Argentina, Brazil, South Africa, India, and China) where the agriculture is a major part of the total economy. Other GM crops include insect-resistant maize and herbicide-tolerant maize, cotton, and rapeseed varieties.
GM Foods currently
Currently, there are a of number of foods of which a genetically modified version exists.
Food
Properties of the genetically modified variety
Trade name and the company which produced initial version
Specific genetic modification
Percent the genetically modified version occupies of the given foods' agriculture in USA
Percent this GMF takes up of agriculture compared to its non-GMF version, globally
Soybeans
Resistant to herbicides
Roundup Ready, Monsanto
Herbicide resistant gene taken from bacteria inserted into soy bean
TBA
TBA
Corn
Resistance to certain pesticides (tolerating crop spray - this way a farmer can use amounts of pesticides which would normally kill the plant, without harming it)
TBA
New gene added/transferred into plant genome
TBA
TBA
Cotton
Pest-resistant cotton
TBA
New gene added/transferred into plant genome
TBA
TBA
Tomatoes
Variety that does not rot (degrade) as fast - the genetically modified tomatoes do not produce a substance that normally causes tomatoes to rot.
E.g. FlavrSavr
First genetically modified tomatoes contained genes that made them resistant to antibiotics. After concern from doctors and the medical community, tomatoes are now genetically modified in an alternative way
TBA
TBA
Potatoes
TBA
TBA
Rapeseed (Canola)
Resistance to certain pesticides (tolerating crop spray)
TBA
New gene added/transferred into plant genome
TBA
TBA
Sugar cane
Resistance to certain pesticides (tolerating crop spray)
TBA
New gene added/transferred into plant genome
TBA
TBA
Sweet corn
Produces its own insecticide (a toxin to insects, so insect attacks are less likely)
Bt corn
Insect-killing gene added to the plant. The gene comes from the bacteria Bacillus thuringiensis.
TBA
TBA
Rice
Genetically modified to contain high amounts of Vitamin A (beta-carotene)
"Golden rice"
Three new genes implanted: two from daffodils and the third from a bacterium
TBA
TBA
Abundance of GM crops
Between 1995 and 2005, the total surface area of land cultivated with GMOs had increased by a factor of 50, from 17,000 km² (4.2 million acres) to 900,000 km² (222 million acres), of which 55 percent were Brazil.
Although most GM crops are grown in North America, in recent years there has been rapid growth in the area sown in developing countries. For instance in 2005 the largest increase in crop area planted to GM crops (soybeans) was in Brazil (94,000 km² in 2005 versus 50,000 km² in 2004.)There has also been rapid and continuing expansion of GM cotton varieties in India since 2002. (Cotton is a major source of vegetable cooking oil and animal feed.) It is predicted that in 2006/7 32,000 km² of GM cotton will be harvested in India (up more than 100 percent from the previous season). Indian national average cotton yields of GM cotton were seven times lower in 2002, because the parental cotton plant used in the genetic engineered was not well suited to the climate of India and failed. The publicity given to transgenic trait Bt insect resistance has encouraged the adoption of better performing hybrid cotton varieties, and the Bt trait has substantially reduced losses to insect predation. Economic and environmental benefits of GM cotton in India to the individual farmer have been documented.
In 2003, countries that grew 99 percent of the global transgenic crops were the United States (63 percent), Argentina (21 percent), Canada (6 percent), Brazil (4 percent), China (4 percent), and South Africa (1 percent).The Grocery Manufacturers of America estimate that 75 percent of all processed foods in the U.S. contain a GM ingredient . In particular, Bt corn, which produces the pesticide within the plant itself is widely grown, as are soybeans genetically designed to tolerate glyphosate herbicides. These constitute "input-traits" are aimed to financially benefit the producers, have indirect environmental benefits and marginal cost benefits to consumers.
In the US, by 2006 89% of the planted area of soybeans, 83 percent of cotton, and 61 percent maize was genetically modified varieties. Genetically modified soybeans carried herbicide tolerant traits only, but maize and cotton carried both herbicide tolerance and insect protection traits (the latter largely the Bacillus thuringiensis Bt insecticidal protein). In the period 2002 to 2006, there were significant increases in the area planted to Bt protected cotton and maize, and herbicide tolerant maize also increased in sown area.
However, several studies have found that genetically modified varieties of plants do not produce higher yields than normal plants.
Coexistence and traceability
In many parts of the world such as the European Union, Japan, Malaysia and Australia consumers demand labelling so they can exercise choice between foods that have genetically modified, conventional or more natural organic origins.This requires a labelling system as well as the reliable separation of GM and non-GM organisms at production level and throughout the whole processing chain.
Research has demonstrated, that coexistence of GM crops can be realised by several agricultural measures, such as isolation distances or biological containment strategies.
For traceability, the OECD has introduced a "unique identifier" which is given to any GMO when it is approved. This unique identifier must be forwarded at every stage of processing.
Many countries have established labelling regulations and guidelines on coexistence and traceability. Research projects such as Co-Extra, SIGMEA and Transcontainer are aimed at investigating improved methods for ensuring coexistence and providing stakeholders the tools required for the implementation of coexistence and traceability.
The GM food controversy is a dispute over the advantages and disadvantages of genetically modified food crops. See Genetically modified food controversies.init
Debate around the world
Some argue that there is more than enough food in the world (morons) and that the hunger crisis is caused by problems in food distribution and politics, not production, so people should not be offered food that may carry some degree of risk.
Others oppose genetic engineering on the grounds that genetic modifications might have unforeseen consequences, both in the initially modified organisms and their environments. For example, certain strains of maize have been developed that are toxic to plant eating insects (see Bt corn). It has been alleged those strains cross-pollinated with other varieties of wild and domestic maize and passed on these genes with a putative impact on Maize biodiversity.Subsequent to the publication of these results, several scientists pointed out that the conclusions were based on experiments with design flaws. It is well known that the results from polymerase chain reaction (PCR) methods of analysing DNA can often be confounded by sample contamination and experimental artifacts. Appropriate controls can be included in experiments to eliminate these as a possible explanation of the results - however these controls were not included in the methods used by Quist and Chapela. After this criticism Nature, the scientific journal where this data was originally published concluded that "the evidence available is not sufficient to justify the publication of the original paper". More recent attempts to replicate the original studies have concluded that genetically modified corn is absent from southern Mexico in 2003 and 2004 . Also in dispute is the impact on biodiversity of the introgression of transgenes into wild populations. Unless a transgene offers a massive selective advantage in a wild population, a transgene that enters such a population will be maintained at a low gene frequency. In such situations it can be argued that such an introgression actually increases biodiversity rather than lowers it.
Activists opposed to genetic engineering say that with current recombinant technology there is no way to ensure that genetically modified organisms will remain under control, and the use of this technology outside secure laboratory environments carries potentially unacceptable risks to both farmed and wild ecosystems.
Potential impact on biodiversity may occur if herbicide-tolerant crops are sprayed with herbicide to the extent that no wild plants ('weeds') are able to survive. Plants toxic to insects may mean insect-free crops. This could result in declines in other wildlife (e.g. birds) which feed on weed seeds and/or insects for food resources. The recent (2003) farm scale studies in the UK found this to be the case with GM sugar beet and GM rapeseed, but not with GM maize (though in the last instance, the non-GM comparison maize crop had also been treated with environmentally-damaging pesticides subsequently (2004) withdrawn from use in the EU).
Although some scientists have claimed that selective breeding is a form of genetic engineering, (e.g., maize was modified from teosinte, dogs have evolved with human intervention over the course of tens of thousands of years from wolves), others assert that modern transgenesis-based genetic engineering is capable of delivering changes faster than, and sometimes of different types from, traditional breeding methods.
Proponents of current genetic techniques as applied to food plants cite the benefits that the technology can have, for example, in the harsh agricultural conditions of Africa. They say that with modifications, existing crops would be able to thrive under the relatively hostile conditions providing much needed food to their people. Proponents also cite golden rice and golden rice 2, genetically engineered rice varieties (still under development) that contain elevated vitamin A levels. There is hope that this rice may alleviate vitamin A deficiency that contributes to the death of millions and permanent blindness of 500,000 annually. Although GM crops have the potential to be a crucial element in the solution for global hunger, one must not overlook the daunting fact that GM crops are not fecund. Farmers must buy GM seeds every year which makes them depended on distributors that charge more for GM seeds than regular seeds. Also seed distribution can be very difficult for countries with poor infrastructure, usually the countries that need them the most.
Proponents say that genetically-engineered crops are not significantly different from those modified by nature or humans in the past, and are as safe or even safer than such methods. There is gene transfer between unicellular eukaryotes and prokaryotes. There have been no known genetic catastrophes as a result of this. They argue that animal husbandry, Food Irradiation and crop breeding are also forms of genetic engineering that use artificial selection instead of modern genetic modification techniques. It is politics, they argue, not economics or science, that causes their work to be closely investigated, and for different standards to apply to it than those applied to other forms of agricultural technology.
Proponents also note that species or genetic barriers have been crossed in nature in the past. An oft-cited example is today's modern red wheat variety, which is the result of two natural crossings made long ago. It is made up of three groups of seven chromosomes. Each of those three groups came from a different wild wheat grass. First, a cross between two of the grasses occurred, creating the durum wheats, which were the commercial grains of the first civilizations up through the Roman Republic. Then a cross occurred between that 14-chromosome durum wheat and another wild grass to create what became modern red wheat at the time of the Roman Empire.
Future developments
Future envisaged applications of GMOs are diverse and include drugs in food, bananas that produce human vaccines against infectious diseases such as Hepatitis B, metabolically engineered fish that mature more quickly, fruit and nut trees that yield years earlier, and plants that produce new plastics with unique properties. While their practicality or efficacy in commercial production has yet to be fully tested, the next decade may see exponential increases in GM product development as researchers gain increasing access to genomic resources that are applicable to organisms beyond the scope of individual projects. Safety testing of these products will also at the same time be necessary to ensure that the perceived benefits will indeed outweigh the perceived and hidden costs of development. Plant scientists, backed by results of modern comprehensive profiling of crop composition, point out that crops modified using GM techniques are less likely to have unintended changes than are conventionally bred crops.
Jom belajar Bio
What is Genetic Engineering?
Genetic engineering is a laboratory technique used by scientists to change the DNA of living organisms.
DNA is the blueprint for the individuality of an organism. The organism relies upon the information stored in its DNA for the management of every biochemical process. The life, growth and unique features of the organism depend on its DNA. The segments of DNA which have been associated with specific features or functions of an organism are called genes.
Molecular biologists have discovered many enzymes which change the structure of DNA in living organisms. Some of these enzymes can cut and join strands of DNA. Using such enzymes, scientists learned to cut specific genes from DNA and to build customized DNA using these genes. They also learned about vectors, strands of DNA such as viruses, which can infect a cell and insert themselves into its DNA.
With this knowledge, scientists started to build vectors which incorporated genes of their choosing and used the new vectors to insert these genes into the DNA of living organisms. Genetic engineers believe they can improve the foods we eat by doing this. For example, tomatoes are sensitive to frost. This shortens their growing season. Fish, on the other hand, survive in very cold water. Scientists identified a particular gene which enables a flounder to resist cold and used the technology of genetic engineering to insert this 'anti-freeze' gene into a tomato. This makes it possible to extend the growing season of the tomato.
At first glance, this might look exciting to some people. Deeper consideration reveals serious dangers.
Genetic engineering is a laboratory technique used by scientists to change the DNA of living organisms.
DNA is the blueprint for the individuality of an organism. The organism relies upon the information stored in its DNA for the management of every biochemical process. The life, growth and unique features of the organism depend on its DNA. The segments of DNA which have been associated with specific features or functions of an organism are called genes.
Molecular biologists have discovered many enzymes which change the structure of DNA in living organisms. Some of these enzymes can cut and join strands of DNA. Using such enzymes, scientists learned to cut specific genes from DNA and to build customized DNA using these genes. They also learned about vectors, strands of DNA such as viruses, which can infect a cell and insert themselves into its DNA.
With this knowledge, scientists started to build vectors which incorporated genes of their choosing and used the new vectors to insert these genes into the DNA of living organisms. Genetic engineers believe they can improve the foods we eat by doing this. For example, tomatoes are sensitive to frost. This shortens their growing season. Fish, on the other hand, survive in very cold water. Scientists identified a particular gene which enables a flounder to resist cold and used the technology of genetic engineering to insert this 'anti-freeze' gene into a tomato. This makes it possible to extend the growing season of the tomato.
At first glance, this might look exciting to some people. Deeper consideration reveals serious dangers.
Thursday, August 7, 2008
SMKTD...dulu dan kini...
Sudah hampir tiga dekad aku berada di smktd ni... Akhir tahun 70-an dulu aku di sini sebagai pelajar. Aku masih ingat lagi guru Matematik, Cikgu Asaad, guru Sejarah Cikgu Suratman, guru
Sains Pertanian Cikgu Samuji, guru Geografi Cikgu Zainudin (Pak Din) ... dan ramai lagi. Yang aku tak dapat lupa Cikgu Pak Siman, guru Kimia yang sangat garang, rasa kecut perut bila dia masuk. Kalau tak dapat jawab soalan berdiri sampai dapat jawab soalan, kalau tak berdiri sampai habis masa. Seorang lagi guru goegrafi, Cikgu Shamsiah, kalau tak dapat jawab soalan kena cubit kat perut, sakit... Itulah antara kenangan di smktd dulu...Terima kasih cikgu-cikgu ku.
Lepas beberapa tahun meninggalkan smktd aku masuk balik pada tahun 1987 sebagai guru Bio, mengajar tingkatan 6.
Kenagan manis menjadi guru di smktd... antaranya pada tahun 1989 keputusan peperiksaan STPM, 3 orang pelajar berjaya mendapat 5PA. Semuanya dah berjaya jadi doktor sekarang.
Begitu cepat masa berlalu... kalau dulu waktu aku jadi pelajar, tak ada walau sebuah komputer di sekolah ini. Tapi sekarang dah ada banyak komputer.... bepuluh malah beratus. Malah sekarang smktd sudah ada laman blog sendiri, sudah terkenal seantero dunia... Begitulah.. zaman dah berubah, dunia dah maju, smktd pun dah maju... Aku sayang smktd dan seluruh warganya seperti aku sayang rumahku dan keluargaku... aku akan terus berada di smktd selagi diperlukan.
Sains Pertanian Cikgu Samuji, guru Geografi Cikgu Zainudin (Pak Din) ... dan ramai lagi. Yang aku tak dapat lupa Cikgu Pak Siman, guru Kimia yang sangat garang, rasa kecut perut bila dia masuk. Kalau tak dapat jawab soalan berdiri sampai dapat jawab soalan, kalau tak berdiri sampai habis masa. Seorang lagi guru goegrafi, Cikgu Shamsiah, kalau tak dapat jawab soalan kena cubit kat perut, sakit... Itulah antara kenangan di smktd dulu...Terima kasih cikgu-cikgu ku.
Lepas beberapa tahun meninggalkan smktd aku masuk balik pada tahun 1987 sebagai guru Bio, mengajar tingkatan 6.
Kenagan manis menjadi guru di smktd... antaranya pada tahun 1989 keputusan peperiksaan STPM, 3 orang pelajar berjaya mendapat 5PA. Semuanya dah berjaya jadi doktor sekarang.
Begitu cepat masa berlalu... kalau dulu waktu aku jadi pelajar, tak ada walau sebuah komputer di sekolah ini. Tapi sekarang dah ada banyak komputer.... bepuluh malah beratus. Malah sekarang smktd sudah ada laman blog sendiri, sudah terkenal seantero dunia... Begitulah.. zaman dah berubah, dunia dah maju, smktd pun dah maju... Aku sayang smktd dan seluruh warganya seperti aku sayang rumahku dan keluargaku... aku akan terus berada di smktd selagi diperlukan.
Subscribe to:
Posts (Atom)
