In 1045, the Byzantine Empire conquered Bagratid Armenia. Soon, the other Armenian states fell under Byzantine control as well. The Byzantine rule was short lived, as in 1071 Seljuk Turks defeated the Byzantines and conquered Armenia at the Battle of Manzikert, establishing the Seljuk Empire. To escape death or servitude at the hands of those who had assassinated his relative, Gagik II, King of Ani, an Armenian named Roupen, went with some of his countrymen into the gorges of the Taurus Mountains and then into Tarsus of Cilicia. The Byzantine governor of the palace gave them shelter where the Armenian Kingdom of Cilicia was eventually established on 6 January 1198 under King Leo I, a descendant of Prince Roupen.


When did the Seljuk Turks beat the Byzantines?


What was the outcome of the Battle of Manzikert for the Seljuk Turks?


Which family overthrew the Seljuk Turks?

The Seljuk Empire soon started to collapse. In the early 12th century, Armenian princes of the Zakarid noble family drove out the Seljuk Turks and established a semi-independent Armenian principality in Northern and Eastern Armenia, known as Zakarid Armenia, which lasted under the patronage of the Georgian Kingdom. The noble family of Orbelians shared control with the Zakarids in various parts of the country, especially in Syunik and Vayots Dzor, while the Armenian family of Hasan-Jalalians controlled provinces of Artsakh and Utik as the Kingdom of Artsakh.


What principality did the Zakarid family form?


What area did the Orbelians and Zakarids command together?


What area did the Hasan-jalalians command?


When did the Seljuk Empire experience it's decline?


In the 16th century, the Ottoman Empire and Safavid Empire divided Armenia. From the early 16th century, both Western Armenia and Eastern Armenia fell under Iranian Safavid rule. Owing to the century long Turco-Iranian geo-political rivalry that would last in Western Asia, significant parts of the region were frequently fought over between the two rivalling empires. From the mid 16th century with the Peace of Amasya, and decisively from the first half of the 17th century with the Treaty of Zuhab until the first half of the 19th century, Eastern Armenia was ruled by the successive Iranian Safavid, Afsharid and Qajar empires, while Western Armenia remained under Ottoman rule.


Who controlled Western Armenia between the 16 and 19th Century?


Who controlled Eastern Armenia between the 16 and 19th Century?


How long did the Turco-Iranian rivalry last?


How many Armenians were slaughtered between 1894-1896

While Western Armenia still remained under Ottoman rule, the Armenians were granted considerable autonomy within their own enclaves and lived in relative harmony with other groups in the empire (including the ruling Turks). However, as Christians under a strict Muslim social system, Armenians faced pervasive discrimination. When they began pushing for more rights within the Ottoman Empire, Sultan ‘Abdu’l-Hamid II, in response, organized state-sponsored massacres against the Armenians between 1894 and 1896, resulting in an estimated death toll of 80,000 to 300,000 people. The Hamidian massacres, as they came to be known, gave Hamid international infamy as the "Red Sultan" or "Bloody Sultan."


What prompted the state-sponsored slaughter of Armenians?


What nicknames was Sultan 'Abdu'l-Hamid II given?


What was the name given to the slaughter of the Armenians between 1894-1896?


What type of social system was in place under the Ottoman Empire?


What is another name for the Armenian Revolutionary Federation?

During the 1890s, the Armenian Revolutionary Federation, commonly known as Dashnaktsutyun, became active within the Ottoman Empire with the aim of unifying the various small groups in the empire that were advocating for reform and defending Armenian villages from massacres that were widespread in some of the Armenian-populated areas of the empire. Dashnaktsutyun members also formed fedayi groups that defended Armenian civilians through armed resistance. The Dashnaks also worked for the wider goal of creating a "free, independent and unified" Armenia, although they sometimes set aside this goal in favor of a more realistic approach, such as advocating autonomy.


Which Dashnak groups helped protect Armenian citizens?


The Ottoman Empire began to collapse, and in 1908, the Young Turk Revolution overthrew the government of Sultan Hamid. In April 1909, the Adana massacre occurred in the Adana Vilayet of the Ottoman Empire resulting in the deaths of as many as 20,000–30,000 Armenians. The Armenians living in the empire hoped that the Committee of Union and Progress would change their second-class status. Armenian reform package (1914) was presented as a solution by appointing an inspector general over Armenian issues.


How many Armenians died in the Adana Massacre?


When was the Armenian Reform package introduced?


What instigated conflict between the Ottoman and Russian Empire?

When World War I broke out leading to confrontation between the Ottoman Empire and the Russian Empire in the Caucasus and Persian Campaigns, the new government in Istanbul began to look on the Armenians with distrust and suspicion. This was because the Imperial Russian Army contained a contingent of Armenian volunteers. On 24 April 1915, Armenian intellectuals were arrested by Ottoman authorities and, with the Tehcir Law (29 May 1915), eventually a large proportion of Armenians living in Anatolia perished in what has become known as the Armenian Genocide.


When did the Tehcir Law come to fruition?


Which army had a group of Armenian volunteers fighting for them?


What do the Armenians see the events of 1915-1917 as?

The genocide was implemented in two phases: the wholesale killing of the able-bodied male population through massacre and subjection of army conscripts to forced labour, followed by the deportation of women, children, the elderly and infirm on death marches leading to the Syrian desert. Driven forward by military escorts, the deportees were deprived of food and water and subjected to periodic robbery, rape, and massacre. There was local Armenian resistance in the region, developed against the activities of the Ottoman Empire. The events of 1915 to 1917 are regarded by Armenians and the vast majority of Western historians to have been state-sponsored mass killings, or genocide.


How many phases were there to the Armenian Genocide?


What did the first phase of the Armenian Genocide involve?


What did the second phase of the Armenian Genocide involve?


Where did the Armenian Genocide death marches push the deportees to?


How many Armenians died during the second phase of the Armenian Genocide between 1915-1916??

Turkish authorities deny the genocide took place to this day. The Armenian Genocide is acknowledged to have been one of the first modern genocides. According to the research conducted by Arnold J. Toynbee, an estimated 600,000 Armenians died during deportation from 1915–16). This figure, however, accounts for solely the first year of the Genocide and does not take into account those who died or were killed after the report was compiled on the 24th May 1916. The International Association of Genocide Scholars places the death toll at "more than a million". The total number of people killed has been most widely estimated at between 1 and 1.5 million.


Who contests the existence of the Armenian Genocide?


What is the estimated sum of people who died during the Armenian Genocide?


Who put together a report about the Armenian Genocide?


Who was in charge of the Russian Caucasus Army of Imperial forces?

Although the Russian Caucasus Army of Imperial forces commanded by Nikolai Yudenich and Armenians in volunteer units and Armenian militia led by Andranik Ozanian and Tovmas Nazarbekian succeeded in gaining most of Ottoman Armenia during World War I, their gains were lost with the Bolshevik Revolution of 1917.[citation needed] At the time, Russian-controlled Eastern Armenia, Georgia, and Azerbaijan attempted to bond together in the Transcaucasian Democratic Federative Republic. This federation, however, lasted from only February to May 1918, when all three parties decided to dissolve it. As a result, the Dashnaktsutyun government of Eastern Armenia declared its independence on 28 May as the First Republic of Armenia under the leadership of Aram Manukian.


Who was the leader of the Armenian militia?


Who formed the Transcaucasian Democratic Federative Republic?


When did the Dashnaktsutyun declare independence?


At the end of the war, the victorious powers sought to divide up the Ottoman Empire. Signed between the Allied and Associated Powers and Ottoman Empire at Sèvres on 10 August 1920, the Treaty of Sèvres promised to maintain the existence of the Armenian republic and to attach the former territories of Ottoman Armenia to it. Because the new borders of Armenia were to be drawn by United States President Woodrow Wilson, Ottoman Armenia was also referred to as "Wilsonian Armenia." In addition, just days prior, on 5 August 1920, Mihran Damadian of the Armenian National Union, the de facto Armenian administration in Cilicia, declared the independence of Cilicia as an Armenian autonomous republic under French protectorate.


What is another name for Ottoman Armenia?


Which US president specified the new Armenian borders?


When was the Treaty of Alexandropol sanctioned?

In 1920, Turkish nationalist forces invaded the fledgling Armenian republic from the east. Turkish forces under the command of Kazım Karabekir captured Armenian territories that Russia had annexed in the aftermath of the 1877–1878 Russo-Turkish War and occupied the old city of Alexandropol (present-day Gyumri). The violent conflict finally concluded with the Treaty of Alexandropol on 2 December 1920. The treaty forced Armenia to disarm most of its military forces, cede all former Ottoman territory granted to it by the Treaty of Sèvres, and to give up all the "Wilsonian Armenia" granted to it at the Sèvres treaty. Simultaneously, the Soviet Eleventh Army, under the command of Grigoriy Ordzhonikidze, invaded Armenia at Karavansarai (present-day Ijevan) on 29 November. By 4 December, Ordzhonikidze's forces entered Yerevan and the short-lived Armenian republic collapsed.


What city did current day Gyumri used to be called?


When did the Armenian republic breakdown?


What year did Turkish nationalists seize the Armenian Republic?


When was the Transcaucasian SFSR formed?

Armenia was annexed by Bolshevist Russia and along with Georgia and Azerbaijan, it was incorporated into the Soviet Union as part of the Transcaucasian SFSR (TSFSR) on 4 March 1922. With this annexation, the Treaty of Alexandropol was superseded by the Turkish-Soviet Treaty of Kars. In the agreement, Turkey allowed the Soviet Union to assume control over Adjara with the port city of Batumi in return for sovereignty over the cities of Kars, Ardahan, and Iğdır, all of which were part of Russian Armenia.


The Soviet Union gained control over which city following the Treaty of Kars?


What did Turkey gain from the Treaty of Kars?


Who provided the Armenians with supplies?

The TSFSR existed from 1922 to 1936, when it was divided up into three separate entities (Armenian SSR, Azerbaijan SSR, and Georgian SSR). Armenians enjoyed a period of relative stability under Soviet rule. They received medicine, food, and other provisions from Moscow, and communist rule proved to be a soothing balm in contrast to the turbulent final years of the Ottoman Empire. The situation was difficult for the church, which struggled under Soviet rule. After the death of Vladimir Lenin, Joseph Stalin took the reins of power and began an era of renewed fear and terror for Armenians.


When did the TSFSR break up into three parts?


Fears decreased when Stalin died in 1953 and Nikita Khruschev emerged as the Soviet Union's new leader. Soon, life in Soviet Armenia began to see rapid improvement. The church, which suffered greatly under Stalin, was revived when Catholicos Vazgen I assumed the duties of his office in 1955. In 1967, a memorial to the victims of the Armenian Genocide was built at the Tsitsernakaberd hill above the Hrazdan gorge in Yerevan. This occurred after mass demonstrations took place on the tragic event's fiftieth anniversary in 1965.


When was the Armenian Genocide Memorial constructed?


Where is the memorial for the Armenian Genocide?


In what year did Armenia suffer from a catastrophic earthquake?

During the Gorbachev era of the 1980s, with the reforms of Glasnost and Perestroika, Armenians began to demand better environmental care for their country, opposing the pollution that Soviet-built factories brought. Tensions also developed between Soviet Azerbaijan and its autonomous district of Nagorno-Karabakh, a majority-Armenian region separated by Stalin from Armenia in 1923. About 484,000 Armenians lived in Azerbaijan in 1970. The Armenians of Karabakh demanded unification with Soviet Armenia. Peaceful protests in Yerevan supporting the Karabakh Armenians were met with anti-Armenian pogroms in the Azerbaijani city of Sumgait. Compounding Armenia's problems was a devastating earthquake in 1988 with a moment magnitude of 7.2.


How man Armenians resided in Azerbaijan in 1970?


When was Nagorno-Karabakh removed from Armenia?


Who partitioned Nagorno-Karabakh from Armenia?


Gorbachev's inability to alleviate any of Armenia's problems created disillusionment among the Armenians and fed a growing hunger for independence. In May 1990, the New Armenian Army (NAA) was established, serving as a defence force separate from the Soviet Red Army. Clashes soon broke out between the NAA and Soviet Internal Security Forces (MVD) troops based in Yerevan when Armenians decided to commemorate the establishment of the 1918 First Republic of Armenia. The violence resulted in the deaths of five Armenians killed in a shootout with the MVD at the railway station. Witnesses there claimed that the MVD used excessive force and that they had instigated the fighting.


Who started the fight between the MVD and the NAA in 1918?


How many people died as a result of the MVD and NAA clash in 1918?


Continued fighting transpired between the Armenians and Soviets in which city?

Further firefights between Armenian militiamen and Soviet troops occurred in Sovetashen, near the capital and resulted in the deaths of over 26 people, mostly Armenians. The pogrom of Armenians in Baku in January 1990 forced almost all of the 200,000 Armenians in the Azerbaijani capital Baku to flee to Armenia. On 17 March 1991, Armenia, along with the Baltic states, Georgia and Moldova, boycotted a nationwide referendum in which 78% of all voters voted for the retention of the Soviet Union in a reformed form.


Where did the Armenians living in Baku escape to during the January 1990 massacre?


When did Armenia reject the referendum proposing the retention of the Soviet Union?


When did Turkey decide to become part of the blockade against Armenia?

Ter-Petrosyan led Armenia alongside Defense Minister Vazgen Sargsyan through the Nagorno-Karabakh War with neighboring Azerbaijan. The initial post-Soviet years were marred by economic difficulties, which had their roots early in the Karabakh conflict when the Azerbaijani Popular Front managed to pressure the Azerbaijan SSR to instigate a railway and air blockade against Armenia. This move effectively crippled Armenia's economy as 85% of its cargo and goods arrived through rail traffic. In 1993, Turkey joined the blockade against Armenia in support of Azerbaijan.


How does Armenia get most of it's commodities?


Who did Armenia fight in teh Nagorno-Karabakh War?


What prevented Armenia from getting it's commodities?


What percent of Armenias commodities were transported via rail traffic?


The Karabakh war ended after a Russian-brokered cease-fire was put in place in 1994. The war was a success for the Karabakh Armenian forces who managed to capture 16% of Azerbaijan's internationally recognised territory including Nagorno-Karabakh itself. Since then, Armenia and Azerbaijan have held peace talks, mediated by the Organisation for Security and Co-operation in Europe (OSCE). The status of Karabakh has yet to be determined. The economies of both countries have been hurt in the absence of a complete resolution and Armenia's borders with Turkey and Azerbaijan remain closed. By the time both Azerbaijan and Armenia had finally agreed to a ceasefire in 1994, an estimated 30,000 people had been killed and over a million had been displaced.


Armenia has closed borders with which two countries?


How many people died as a result of the fighting betwen Armenia and Azerbaijan?


Who gained the most from the Karabakh War?


What is the lowest score on the Democracy Score scale?

International observers of Council of Europe and US Department of State have questioned the fairness of Armenia's parliamentary and presidential elections and constitutional referendum since 1995, citing polling deficiencies, lack of cooperation by the Electoral Commission, and poor maintenance of electoral lists and polling places. Freedom House categorized Armenia in its 2008 report as a "Semi-consolidated Authoritarian Regime" (along with Moldova, Kosovo, Kyrgyzstan, and Russia) and ranked Armenia 20th among 29 nations in transition, with a Democracy Score of 5.21 out of 7 (7 represents the lowest democratic progress).


What does the Freedom House classify Armenia as?


What makes Armenia's presidential elections faulty?


With who does Armenia have bad relations?

Armenia presently maintains good relations with almost every country in the world, with two major exceptions being its immediate neighbours, Turkey and Azerbaijan. Tensions were running high between Armenians and Azerbaijanis during the final years of the Soviet Union. The Nagorno-Karabakh War dominated the region's politics throughout the 1990s. The border between the two rival countries remains closed up to this day, and a permanent solution for the conflict has not been reached despite the mediation provided by organisations such as the OSCE.


Is the border between Armenia and Azerbaijan open or closed?


When did Turkey close off its border with Armenia?

Turkey also has a long history of poor relations with Armenia over its refusal to acknowledge the Armenian Genocide. Turkey was one of the first countries to recognize the Republic of Armenia (the 3rd republic) after its independence from the USSR in 1991. Despite this, for most of the 20th century and early 21st century, relations remain tense and there are no formal diplomatic relations between the two countries due to Turkey's refusal to establish them for numerous reasons. During the Nagorno-Karabakh War and citing it as the reason, Turkey illegally closed its land border with Armenia in 1993. It has not lifted its blockade despite pressure from the powerful Turkish business lobby interested in Armenian markets.


Which country claims the Armenian Genocide didn't occur?


When did Armenia gain independence from the USSR?


Who wants the border between Turkey and Armenia opened?


When did Armenia and Turkey initiate an attempt to reopen their border?

On 10 October 2009, Armenia and Turkey signed protocols on normalisation of relationships, which set a timetable for restoring diplomatic ties and reopening their joint border. The ratification of those had to be made in the national parliaments. In Armenia it passed through the required by legislation approval of the Constitutional Court and was sent to the parliament for the final ratification. The President had made multiple public announcements, both in Armenia and abroad, that as the leader of the political majority of Armenia he assured the ratification of the protocols if Turkey also ratified them. Despite this, the process stopped, as Turkey continuously added more preconditions to its ratification and also "delayed it beyond any reasonable time-period".


Who made it difficult to ratify the protocols to reopen the Armenian/Turkey border?


How did Turkey thwart the ratification of these protocols?


Russia has a military base in which city in Armenia?

Due to its position between two unfriendly neighbours, Armenia has close security ties with Russia. At the request of the Armenian government, Russia maintains a military base in the northwestern Armenian city of Gyumri as a deterrent against Turkey.[citation needed] Despite this, Armenia has also been looking toward Euro-Atlantic structures in recent years. It maintains good relations with the United States especially through its Armenian diaspora. According to the US Census Bureau, there are 427,822 Armenians living in the country.


How many Armenians reside in the United States?


Why does Russia have a miltary base In Gyumri?


Who gave Russia permission to have a military base in Gyumri?


How many of Armenias inhabitants approve of becoming part of the EU?

Armenia is also a member of the Council of Europe, maintaining friendly relations with the European Union, especially with its member states such as France and Greece. A 2005 survey reported that 64% of Armenia's population would be in favor of joining the EU. Several Armenian officials have also expressed the desire for their country to eventually become an EU member state, some[who?] predicting that it will make an official bid for membership in a few years.[citation needed] In 2004 its forces joined KFOR, a NATO-led international force in Kosovo. It is also an observer member of the Eurasian Economic Community and the Non-Aligned Movement.


What are some states join Armenia in the Council of Europe?


When can the EU expect Armenia to attempt to join it?


The Armenian Army, Air Force, Air Defence, and Border Guard comprise the four branches of the Armed Forces of the Republic of Armenia. The Armenian military was formed after the collapse of the Soviet Union in 1991 and with the establishment of the Ministry of Defence in 1992. The Commander-in-Chief of the military is the President of Armenia, Serzh Sargsyan. The Ministry of Defence is in charge of political leadership, currently headed by Colonel General Seyran Ohanyan, while military command remains in the hands of the General Staff, headed by the Chief of Staff, who is currently Colonel General Yuri Khatchaturov.


When was the Ministry of Defence founded?


What are the four branches of the Armenian Armed Forces?


Who is in charge of the the Armenian military?


Who is in charge of the Ministry of Defence?


Armenia is member of Collective Security Treaty Organisation (CSTO) along with Belarus, Kazakhstan, Kyrgyzstan, Russia, Tajikistan and Uzbekistan. It participates in NATO's Partnership for Peace (PiP) program and is in a NATO organisation called Euro-Atlantic Partnership Council (EAPC). Armenia has engaged in a peacekeeping mission in Kosovo as part of non-NATO KFOR troops under Greek command. Armenia also had 46 members of its military peacekeeping forces as a part of the Coalition Forces in Iraq War until October 2008.


When did Armenia remove its peacekeepers from Iraq?


Within each province are communities (hamaynkner, singular hamaynk). Each community is self-governing and consists of one or more settlements (bnakavayrer, singular bnakavayr). Settlements are classified as either towns (kaghakner, singular kaghak) or villages (gyugher, singular gyugh). As of 2007[update], Armenia includes 915 communities, of which 49 are considered urban and 866 are considered rural. The capital, Yerevan, also has the status of a community. Additionally, Yerevan is divided into twelve semi-autonomous districts.


Does Armenia have more rural or uban hamaynker?


What is the Armenian term for settlment?


What group is opening a research center in Armenia?

The economy relies heavily on investment and support from Armenians abroad. Before independence, Armenia's economy was largely industry-based – chemicals, electronics, machinery, processed food, synthetic rubber, and textile – and highly dependent on outside resources. The republic had developed a modern industrial sector, supplying machine tools, textiles, and other manufactured goods to sister republics in exchange for raw materials and energy. Recently, the Intel Corporation agreed to open a research center in Armenia, in addition to other technology companies, signalling the growth of the technology industry in Armenia.


As opposed to an industry-based economy, what industry is Armenia moving to?


The Arnmenian economy depends primarily on what?


What did Armenias industry-based economy consist of?


Was agriculture more important before or after Armenia left the Soviet Union?

Agriculture accounted for less than 20% of both net material product and total employment before the dissolution of the Soviet Union in 1991. After independence, the importance of agriculture in the economy increased markedly, its share at the end of the 1990s rising to more than 30% of GDP and more than 40% of total employment. This increase in the importance of agriculture was attributable to food security needs of the population in the face of uncertainty during the first phases of transition and the collapse of the non-agricultural sectors of the economy in the early 1990s. As the economic situation stabilized and growth resumed, the share of agriculture in GDP dropped to slightly over 20% (2006 data), although the share of agriculture in employment remained more than 40%.


Why did agriculture become so significant for Armenia's economy?


How much of total employment did agriculture account for at the end of the 1990s?


How much of the GDP has agriculture accounted for most recently?


How many people died because of the Spitak earthquake?

Like other newly independent states of the former Soviet Union, Armenia's economy suffers from the breakdown of former Soviet trading patterns. Soviet investment in and support of Armenian industry has virtually disappeared, so that few major enterprises are still able to function. In addition, the effects of the 1988 Spitak earthquake, which killed more than 25,000 people and made 500,000 homeless, are still being felt. The conflict with Azerbaijan over Nagorno-Karabakh has not been resolved. The closure of Azerbaijani and Turkish borders has devastated the economy, because Armenia depends on outside supplies of energy and most raw materials. Land routes through Georgia and Iran are inadequate or unreliable. The GDP fell nearly 60% between 1989 and 1993, but then resumed robust growth. The national currency, the dram, suffered hyperinflation for the first years after its introduction in 1993.


How much did the Armenian GDP decrease from 1989-1993


What is the national currency of Armenia?


What did Armenia declare a cease-fire to in 1994?

Nevertheless, the government was able to make wide-ranging economic reforms that paid off in dramatically lower inflation and steady growth. The 1994 cease-fire in the Nagorno-Karabakh conflict has also helped the economy. Armenia has had strong economic growth since 1995, building on the turnaround that began the previous year, and inflation has been negligible for the past several years. New sectors, such as precious-stone processing and jewellery making, information and communication technology, and even tourism are beginning to supplement more traditional sectors of the economy, such as agriculture.


Since when has Armenia experienced a positive growth in their economy?


What helped Armenia decrease inflation and create study growth in the economy?


What is one of the newer sectors Armenia has in addition to agriculture?


This steady economic progress has earned Armenia increasing support from international institutions. The International Monetary Fund (IMF), World Bank, European Bank for Reconstruction and Development (EBRD), and other international financial institutions (IFIs) and foreign countries are extending considerable grants and loans. Loans to Armenia since 1993 exceed $1.1 billion. These loans are targeted at reducing the budget deficit and stabilizing the currency; developing private businesses; energy; agriculture; food processing; transportation; the health and education sectors; and ongoing rehabilitation in the earthquake zone. The government joined the World Trade Organization on 5 February 2003. But one of the main sources of foreign direct investments remains the Armenian diaspora, which finances major parts of the reconstruction of infrastructure and other public projects. Being a growing democratic state, Armenia also hopes to get more financial aid from the Western World.


How much in loans has Armenia received since 1993?


When did Armenia become a part of the World Trade Organization?


What is the unemployment rate in Armenia?

A liberal foreign investment law was approved in June 1994, and a law on privatisation was adopted in 1997, as well as a program of state property privatisation. Continued progress will depend on the ability of the government to strengthen its macroeconomic management, including increasing revenue collection, improving the investment climate, and making strides against corruption. However, unemployment, which currently stands at around 15%, still remains a major problem due to the influx of thousands of refugees from the Karabakh conflict.


To what does Armenia attribute it's high unemployment rate?


When did Armenia establish a foreign investment law?


When did Armenia establish a law on privatisation?


What percent of Armenian children go to preschool?

In the 1988–89 school year, 301 students per 10,000 population were in specialized secondary or higher education, a figure slightly lower than the Soviet average. In 1989 some 58% of Armenians over age fifteen had completed their secondary education, and 14% had a higher education. In the 1990–91 school year, the estimated 1,307 primary and secondary schools were attended by 608,800 students. Another seventy specialized secondary institutions had 45,900 students, and 68,400 students were enrolled in a total of ten postsecondary institutions that included universities. In addition, 35% of eligible children attended preschools. In 1992 Armenia's largest institution of higher learning, Yerevan State University, had eighteen departments, including ones for social sciences, sciences, and law. Its faculty numbered about 1,300 teachers and its student population about 10,000 students. The National Polytechnic University of Armenia is operating since 1933.


When did the National Polytechnic University of Armenia open?


How many students did Yerevan State University have in 1992?


How many teachers did Yerevan State University have in 1992?


When was Yerevan State Medical University awarded the Order of Labor red Banner?

On the basis of the expansion and development of Yerevan State University a number of higher educational independent Institutions were formed including Medical Institute separated in 1930 which was set up on the basis of medical faculty. In 1980 Yerevan State Medical University was awarded one of the main rewards of the former USSR – the Order of Labor red Banner for training qualified specialists in health care and valuable service in the development of Medical Science. In 1995 YSMI was renamed to YSMU and since 1989 it has been named after Mkhitar Heratsi, the famous medieval doctor. Mkhitar Heratsi was the founder of Armenian Medical school in Cilician Armenia. The great doctor played the same role in Armenian Medical Science as Hippocrates in Western, Galen in Roman, Ibn Sīnā in Arabic medicine.


When was Yerevan State Medical Institute renamed to Yerevan State Medical University?


Who founded the Armenian Medical school in Cilician Armenia?


Which doctor did the YSMU rename itself after?


Who is in charge of releasing the World Directory of Medical Schools?

Foreign students' department for Armenian diaspora established in 1957 later was enlarged and the enrollment of foreign students began. Nowadays the YSMU is a Medical Institution corresponding to international requirements, trains medical staff for not only Armenia and neighbor countries, i.e. Iran, Syria, Lebanon, Georgia, but also many other leading countries all over the world. A great number of foreign students from India, Nepal, Sri Lanka, the USA and Russian Federation study together with Armenian students. Nowadays the university is ranked among famous higher Medical Institutions and takes its honorable place in the World Directory of Medical Schools published by the WHO.


When was the foreign student department for Armenian diaspora created?


Armenian students attend YMSU with foreign students from where?


Other educational institutions in Armenia include the American University of Armenia and the QSI International School of Yerevan. The American University of Armenia has graduate programs in Business and Law, among others. The institution owes its existence to the combined efforts of the Government of Armenia, the Armenian General Benevolent Union, U.S. Agency for International Development, and the University of California. The extension programs and the library at AUA form a new focal point for English-language intellectual life in the city. Armenia also hosts a deployment of OLPC – One Laptopschool Per child XO laptop-tablet schools.


What are the names of some of the other higher education organizations in Armenia?


What are some of the graduate programs available at AUA?


What are some examples of Armenian folk music instruments?

Instruments like the duduk, the dhol, the zurna, and the kanun are commonly found in Armenian folk music. Artists such as Sayat Nova are famous due to their influence in the development of Armenian folk music. One of the oldest types of Armenian music is the Armenian chant which is the most common kind of religious music in Armenia. Many of these chants are ancient in origin, extending to pre-Christian times, while others are relatively modern, including several composed by Saint Mesrop Mashtots, the inventor of the Armenian alphabet. Whilst under Soviet rule, Armenian classical music composer Aram Khatchaturian became internationally well known for his music, for various ballets and the Sabre Dance from his composition for the ballet Gayane.


What is known as one of the most prolific type of religious music in Armenia?


The Armenian Genocide caused widespread emigration that led to the settlement of Armenians in various countries in the world. Armenians kept to their traditions and certain diasporans rose to fame with their music. In the post-Genocide Armenian community of the United States, the so-called "kef" style Armenian dance music, using Armenian and Middle Eastern folk instruments (often electrified/amplified) and some western instruments, was popular. This style preserved the folk songs and dances of Western Armenia, and many artists also played the contemporary popular songs of Turkey and other Middle Eastern countries from which the Armenians emigrated.


Richard Hagopian is perhaps the most famous artist of the traditional "kef" style and the Vosbikian Band was notable in the 1940s and 1950s for developing their own style of "kef music" heavily influenced by the popular American Big Band Jazz of the time. Later, stemming from the Middle Eastern Armenian diaspora and influenced by Continental European (especially French) pop music, the Armenian pop music genre grew to fame in the 1960s and 1970s with artists such as Adiss Harmandian and Harout Pamboukjian performing to the Armenian diaspora and Armenia; also with artists such as Sirusho, performing pop music combined with Armenian folk music in today's entertainment industry.


What type of music had the biggest impact on the kef of the Vosbikian Band?


When did Armenian pop music become popular?


Other Armenian diasporans that rose to fame in classical or international music circles are world-renowned French-Armenian singer and composer Charles Aznavour, pianist Sahan Arzruni, prominent opera sopranos such as Hasmik Papian and more recently Isabel Bayrakdarian and Anna Kasyan. Certain Armenians settled to sing non-Armenian tunes such as the heavy metal band System of a Down (which nonetheless often incorporates traditional Armenian instrumentals and styling into their songs) or pop star Cher. In the Armenian diaspora, Armenian revolutionary songs are popular with the youth. These songs encourage Armenian patriotism and are generally about Armenian history and national heroes.


What type of songs do armenian youth prefer?


What topics do armenian revolutionary songs usually encompass?


Yerevan Vernissage (arts and crafts market), close to Republic Square, bustles with hundreds of vendors selling a variety of crafts on weekends and Wednesdays (though the selection is much reduced mid-week). The market offers woodcarving, antiques, fine lace, and the hand-knotted wool carpets and kilims that are a Caucasus specialty. Obsidian, which is found locally, is crafted into assortment of jewellery and ornamental objects. Armenian gold smithery enjoys a long tradition, populating one corner of the market with a selection of gold items. Soviet relics and souvenirs of recent Russian manufacture – nesting dolls, watches, enamel boxes and so on – are also available at the Vernisage.


What are some examples of soviet memorabilia that can be purchased at Vernissage?


What types of crafts can be purchased at Vernissage?


How many pieces can be found in the Yerevan National Art Gallery?

The National Art Gallery in Yerevan has more than 16,000 works that date back to the Middle Ages, which indicate Armenia's rich tales and stories of the times. It houses paintings by many European masters as well. The Modern Art Museum, the Children’s Picture Gallery, and the Martiros Saryan Museum are only a few of the other noteworthy collections of fine art on display in Yerevan. Moreover, many private galleries are in operation, with many more opening every year, featuring rotating exhibitions and sales.


Where other than the National Art Gallery can one find art on display in Yerevan?


What is the earliest period the National Art Gallery has pieces from?


Which lake is most popular for water sports in Armenia?

A wide array of sports are played in Armenia, the most popular among them being wrestling, weightlifting, judo, association football, chess, and boxing. Armenia's mountainous terrain provides great opportunities for the practice of sports like skiing and climbing. Being a landlocked country, water sports can only be practiced on lakes, notably Lake Sevan. Competitively, Armenia has been successful in chess, weightlifting and wrestling at the international level. Armenia is also an active member of the international sports community, with full membership in the Union of European Football Associations (UEFA) and International Ice Hockey Federation (IIHF). It also hosts the Pan-Armenian Games.


What international sports has Armenia done well at?


What Olympic Sport did Hrant Shahinyan compete in?

Prior to 1992, Armenians would participate in the Olympics representing the USSR. As part of the Soviet Union, Armenia was very successful, winning plenty of medals and helping the USSR win the medal standings at the Olympics on numerous occasions. The first medal won by an Armenian in modern Olympic history was by Hrant Shahinyan (sometimes spelled as Grant Shaginyan), who won two golds and two silvers in gymnastics at the 1952 Summer Olympics in Helsinki. To highlight the level of success of Armenians in the Olympics, Shahinyan was quoted as saying:


What medals did Hrant Shahinyan win at the 1952 Summer Olympics?


Where were the 1952 Summer Olympics held?


What year did Armenia begin competiting in the Olympics seperate from the USSR?


What team won the Soviet football Cup in 1973 and 1975?

Football is also popular in Armenia. The most successful team was the FC Ararat Yerevan team of the 1970s who won the Soviet Cup in 1973 and 1975 and the Soviet Top League in 1973. The latter achievement saw FC Ararat gain entry to the European Cup where – despite a home victory in the second leg – they lost on aggregate at the quarter final stage to eventual winner FC Bayern Munich. Armenia competed internationally as part of the USSR national football team until the Armenian national football team was formed in 1992 after the split of the Soviet Union. Armenia have never qualified for a major tournament although recent improvements saw the team to achieve 44th position in the FIFA World Rankings in September 2011. The national team is controlled by the Football Federation of Armenia. The Armenian Premier League is the highest level football competition in Armenia, and has been dominated by FC Pyunik in recent seasons. The league currently consists of eight teams and relegates to the Armenian First League.


Which team did the FC Ararat lose to in the European Cup?


What FIFA ranking did Armenia hold in 2011?


How many teams does the Armenian Premier League have?


Who provided the funds to rebuild the Armenian sports schools?

Due to the lack of success lately on the international level, in recent years, Armenia has rebuilt 16 Soviet-era sports schools and furnished them with new equipment for a total cost of $1.9 million. The rebuilding of the regional schools was financed by the Armenian government. $9.3 million has been invested in the resort town of Tsaghkadzor to improve the winter sports infrastructure because of dismal performances at recent winter sports events. In 2005, a cycling center was opened in Yerevan with the aim of helping produce world class Armenian cyclists. The government has also promised a cash reward of $700,000 to Armenians who win a gold medal at the Olympics.


What year did Yerevan create a cyclying center?


What prize do Armenians receive from the government if they win a gold medal?


How much money was spent to revamp Tsaghkadzor for winter sports?


How much did Armenia spend to fix up their sports schools?


What type of food is Armenian food most similair to?

Armenian cuisine is as ancient as the history of Armenia, a combination of different tastes and aromas. The food often has quite a distinct aroma. Closely related to eastern and Mediterranean cuisine, various spices, vegetables, fish, and fruits combine to present unique dishes. The main characteristics of Armenian cuisine are a reliance on the quality of the ingredients rather than heavily spicing food, the use of herbs, the use of wheat in a variety of forms, of legumes, nuts, and fruit (as a main ingredient as well as to sour food), and the stuffing of a wide variety of leaves.


What does Armenian cuisine place an emphasis on?


What does Armenian cuisine use to create its distinctive dishes?


What different uses does fruit have in Armenian food?


What is a large domain of prokaryotic microorganisms?

Bacteria (i/bækˈtɪəriə/; singular: bacterium) constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. They are also known to have flourished in manned spacecraft.


What configurations can bacteria can bacteria take?


When is the typical lenght for bacteria?


What is the relationships between plants animals and bacteria?


What amount of bacteria can be found in a gram of soil?

There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants and animals. Bacteria are vital in recycling nutrients, with many of the stages in nutrient cycles dependent on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. In the biological communities surrounding hydrothermal vents and cold seeps, bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. On 17 March 2013, researchers reported data that suggested bacterial life forms thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest part of the Earth's oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, "You can find microbes everywhere — they're extremely adaptable to conditions, and survive wherever they are."


How many bacteria cells can be in a milliltre of fresh water?


How does bacteria help to sustain life in hydrothermal vents and cold seeps?


What deepest part of the ocean was bacteria found?


Can bacteria survive inside rocks under the sea level?


What is the ratio of human/bacteria cells in human flora?

There are approximately ten times as many bacterial cells in the human flora as there are human cells in the body, with the largest number of the human flora being in the gut flora, and a large number on the skin. The vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, and some are beneficial. However, several species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy, and bubonic plague. The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year, mostly in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and are also used in farming, making antibiotic resistance a growing problem. In industry, bacteria are important in sewage treatment and the breakdown of oil spills, the production of cheese and yogurt through fermentation, and the recovery of gold, palladium, copper and other metals in the mining sector, as well as in biotechnology, and the manufacture of antibiotics and other chemicals.


What keeps bacteria at bay in human body?


What type of bacteria can cause infectious diseases?


What are the deadliest diseases caused by bacteria?


What makes bacteria resistant to antibiotic treatment?


What living organisms are bacteria being reffered as?

Once regarded as plants constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.


What vital part is missing in bacteria to eukaryotes?


When did the scientific classification change?


What are two main groups prokaryotes can be divided into?


When did the first antecedents of bacteria appear on Earth?

The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, about 4 billion years ago. For about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota. Although bacterial fossils exist, such as stromatolites, their lack of distinctive morphology prevents them from being used to examine the history of bacterial evolution, or to date the time of origin of a particular bacterial species. However, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea and eukaryotes. Here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea. This involved the engulfment by proto-eukaryotic cells of alphaproteobacterial symbionts to form either mitochondria or hydrogenosomes, which are still found in all known Eukarya (sometimes in highly reduced form, e.g. in ancient "amitochondrial" protozoa). Later on, some eukaryotes that already contained mitochondria also engulfed cyanobacterial-like organisms. This led to the formation of chloroplasts in algae and plants. There are also some algae that originated from even later endosymbiotic events. Here, eukaryotes engulfed a eukaryotic algae that developed into a "second-generation" plastid. This is known as secondary endosymbiosis.


Why were bacteria and archaea dominant forms of life?


What pre-historic group did bacteria evolve from?


How did chloroplast appear in first vegetation?


Are bacteria cells smaller than eukaryotic cells?

Bacteria display a wide diversity of shapes and sizes, called morphologies. Bacterial cells are about one-tenth the size of eukaryotic cells and are typically 0.5–5.0 micrometres in length. However, a few species are visible to the unaided eye — for example, Thiomargarita namibiensis is up to half a millimetre long and Epulopiscium fishelsoni reaches 0.7 mm. Among the smallest bacteria are members of the genus Mycoplasma, which measure only 0.3 micrometres, as small as the largest viruses. Some bacteria may be even smaller, but these ultramicrobacteria are not well-studied.


What is the common name for shapes and forms of bacteria?


What shape does usually cocci type of bacteria can be?

Most bacterial species are either spherical, called cocci (sing. coccus, from Greek kókkos, grain, seed), or rod-shaped, called bacilli (sing. bacillus, from Latin baculus, stick). Elongation is associated with swimming. Some bacteria, called vibrio, are shaped like slightly curved rods or comma-shaped; others can be spiral-shaped, called spirilla, or tightly coiled, called spirochaetes. A small number of species even have tetrahedral or cuboidal shapes. More recently, some bacteria were discovered deep under Earth's crust that grow as branching filamentous types with a star-shaped cross-section. The large surface area to volume ratio of this morphology may give these bacteria an advantage in nutrient-poor environments. This wide variety of shapes is determined by the bacterial cell wall and cytoskeleton, and is important because it can influence the ability of bacteria to acquire nutrients, attach to surfaces, swim through liquids and escape predators.


What type of bacteria usually takes rod-shaped form?


What shape was newly discovered bacteria from deep under Earth?


Can shape of bacteria be beneficial to their survival?


What is the usual form for Neiserria bacteria?

Many bacterial species exist simply as single cells, others associate in characteristic patterns: Neisseria form diploids (pairs), Streptococcus form chains, and Staphylococcus group together in "bunch of grapes" clusters. Bacteria can also be elongated to form filaments, for example the Actinobacteria. Filamentous bacteria are often surrounded by a sheath that contains many individual cells. Certain types, such as species of the genus Nocardia, even form complex, branched filaments, similar in appearance to fungal mycelia.


What type of bacteria is surrounded by a capsule?


What well known bacteria structure chains?


What does typically Staphylococcus look like?


Formation of what can be related to fungal mycelia?


What does bacteria use to adhere to surfaces?

Bacteria often attach to surfaces and form dense aggregations called biofilms or bacterial mats. These films can range from a few micrometers in thickness to up to half a meter in depth, and may contain multiple species of bacteria, protists and archaea. Bacteria living in biofilms display a complex arrangement of cells and extracellular components, forming secondary structures, such as microcolonies, through which there are networks of channels to enable better diffusion of nutrients. In natural environments, such as soil or the surfaces of plants, the majority of bacteria are bound to surfaces in biofilms. Biofilms are also important in medicine, as these structures are often present during chronic bacterial infections or in infections of implanted medical devices, and bacteria protected within biofilms are much harder to kill than individual isolated bacteria.


What is part of secondary structure in the complex formation of bacteria?


What is the purpose of networks of channels in microcolonies?


Which bacteria is more difficult to eradicate?


What is the vital nutriment for Myxobacteria?

Even more complex morphological changes are sometimes possible. For example, when starved of amino acids, Myxobacteria detect surrounding cells in a process known as quorum sensing, migrate toward each other, and aggregate to form fruiting bodies up to 500 micrometres long and containing approximately 100,000 bacterial cells. In these fruiting bodies, the bacteria perform separate tasks; this type of cooperation is a simple type of multicellular organisation. For example, about one in 10 cells migrate to the top of these fruiting bodies and differentiate into a specialised dormant state called myxospores, which are more resistant to drying and other adverse environmental conditions than are ordinary cells.


Why do cells of Myxobacteria migrate towards each other?


How hard to treat bacteria cells in a passive state?


The bacterial cell is surrounded by a cell membrane (also known as a lipid, cytoplasmic or plasma membrane). This membrane encloses the contents of the cell and acts as a barrier to hold nutrients, proteins and other essential components of the cytoplasm within the cell. As they are prokaryotes, bacteria do not usually have membrane-bound organelles in their cytoplasm, and thus contain few large intracellular structures. They lack a true nucleus, mitochondria, chloroplasts and the other organelles present in eukaryotic cells. Bacteria were once seen as simple bags of cytoplasm, but structures such as the prokaryotic cytoskeleton and the localization of proteins to specific locations within the cytoplasm that give bacteria some complexity have been discovered. These subcellular levels of organization have been called "bacterial hyperstructures".


Do bacteria have membrabe-bound organelles in their cytoplasm?


Absence of what make bacteria belong to prokaryotes?


What bacteria was observed as before prokaryotic cytoskeleton was discovered?


What is crucial for biochemical reactions?

Many important biochemical reactions, such as energy generation, use concentration gradients across membranes. The general lack of internal membranes in bacteria means reactions such as electron transport occur across the cell membrane between the cytoplasm and the periplasmic space. However, in many photosynthetic bacteria the plasma membrane is highly folded and fills most of the cell with layers of light-gathering membrane. These light-gathering complexes may even form lipid-enclosed structures called chlorosomes in green sulfur bacteria. Other proteins import nutrients across the cell membrane, or expel undesired molecules from the cytoplasm.


What kind of membrane do bacteria cells are filled with?


How does electron transit occur in bacteria?


Can membrane of bacteria create lipid structure?


Bacteria do not have a membrane-bound nucleus, and their genetic material is typically a single circular DNA chromosome located in the cytoplasm in an irregularly shaped body called the nucleoid. The nucleoid contains the chromosome with its associated proteins and RNA. The phylum Planctomycetes and candidate phylum Poribacteria may be exceptions to the general absence of internal membranes in bacteria, because they appear to have a double membrane around their nucleoids and contain other membrane-bound cellular structures. Like all living organisms, bacteria contain ribosomes, often grouped in chains called polyribosomes, for the production of proteins, but the structure of the bacterial ribosome is different from that of eukaryotes and Archaea. Bacterial ribosomes have a sedimentation rate of 70S (measured in Svedberg units): their subunits have rates of 30S and 50S. Some antibiotics bind specifically to 70S ribosomes and inhibit bacterial protein synthesis. Those antibiotics kill bacteria without affecting the larger 80S ribosomes of eukaryotic cells and without harming the host.


Where is DNA chromosome of bacteria located?


What are the exceptions of non-internal membrane bacteria?


What is the purpose of polyribosomes in bacteria?


What types of intracellar nutrient can bacteria produce?

Some bacteria produce intracellular nutrient storage granules for later use, such as glycogen, polyphosphate, sulfur or polyhydroxyalkanoates. Certain bacterial species, such as the photosynthetic Cyanobacteria, produce internal gas vesicles, which they use to regulate their buoyancy – allowing them to move up or down into water layers with different light intensities and nutrient levels. Intracellular membranes called chromatophores are also found in membranes of phototrophic bacteria. Used primarily for photosynthesis, they contain bacteriochlorophyll pigments and carotenoids. An early idea was that bacteria might contain membrane folds termed mesosomes, but these were later shown to be artifacts produced by the chemicals used to prepare the cells for electron microscopy. Inclusions are considered to be nonliving components of the cell that do not possess metabolic activity and are not bounded by membranes. The most common inclusions are glycogen, lipid droplets, crystals, and pigments. Volutin granules are cytoplasmic inclusions of complexed inorganic polyphosphate. These granules are called metachromatic granules due to their displaying the metachromatic effect; they appear red or blue when stained with the blue dyes methylene blue or toluidine blue. Gas vacuoles, which are freely permeable to gas, are membrane-bound vesicles present in some species of Cyanobacteria. They allow the bacteria to control their buoyancy. Microcompartments are widespread, membrane-bound organelles that are made of a protein shell that surrounds and encloses various enzymes. Carboxysomes are bacterial microcompartments that contain enzymes involved in carbon fixation. Magnetosomes are bacterial microcompartments, present in magnetotactic bacteria, that contain magnetic crystals.


What gas vacuoles are respoonsible for in bacteria?


What are the most common nonliving compositions in bacteria?


How does gas vesicles produced by Cyanobacteria help her to move in water?


In most bacteria, a cell wall is present on the outside of the cell membrane. The cell membrane and cell wall comprise the cell envelope. A common bacterial cell wall material is peptidoglycan (called "murein" in older sources), which is made from polysaccharide chains cross-linked by peptides containing D-amino acids. Bacterial cell walls are different from the cell walls of plants and fungi, which are made of cellulose and chitin, respectively. The cell wall of bacteria is also distinct from that of Archaea, which do not contain peptidoglycan. The cell wall is essential to the survival of many bacteria, and the antibiotic penicillin is able to kill bacteria by inhibiting a step in the synthesis of peptidoglycan.


Are cell walls of bacteria similar to cell walls of plants and fungi?


How can antibiotic penicillin destroy bacteria?


What are the main materials of cell walls of plants and fungi?


Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids. In contrast, gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins. Lipopolysaccharides, also called endotoxins, are composed of polysaccharides and lipid A that is responsible for much of the toxicity of gram-negative bacteria. Most bacteria have the gram-negative cell wall, and only the Firmicutes and Actinobacteria have the alternative gram-positive arrangement. These two groups were previously known as the low G+C and high G+C Gram-positive bacteria, respectively. These differences in structure can produce differences in antibiotic susceptibility; for instance, vancomycin can kill only gram-positive bacteria and is ineffective against gram-negative pathogens, such as Haemophilus influenzae or Pseudomonas aeruginosa. If the bacterial cell wall is entirely removed, it is called a protoplast, whereas if it is partially removed, it is called a spheroplast. β-Lactam antibiotics, such as penicillin, inhibit the formation of peptidoglycan cross-links in the bacterial cell wall. The enzyme lysozyme, found in human tears, also digests the cell wall of bacteria and is the body's main defense against eye infections.


Why gram-negative cell bacteria is more toxic than gram-positive bacteria?


What can different structure of the cell walls of bacteria effect?


What is the main defense of human body against eye infections?


What is the most typical staining technique used to identify acid-fast bacteria?

Acid-fast bacteria, such as Mycobacteria, are resistant to decolorization by acids during staining procedures. The high mycolic acid content of Mycobacteria, is responsible for the staining pattern of poor absorption followed by high retention. The most common staining technique used to identify acid-fast bacteria is the Ziehl-Neelsen stain or acid-fast stain, in which the acid-fast bacilli are stained bright-red and stand out clearly against a blue background. L-form bacteria are strains of bacteria that lack cell walls. The main pathogenic bacteria in this class is Mycoplasma (not to be confused with Mycobacteria).


What is mycolic acid is responsible for in Mycobacteria?


What helps Mycobacteria be resistant to decolorization?


What is the main pathogenic bacteria in L-form class ?


Fimbriae (sometimes called "attachment pili") are fine filaments of protein, usually 2–10 nanometres in diameter and up to several micrometers in length. They are distributed over the surface of the cell, and resemble fine hairs when seen under the electron microscope. Fimbriae are believed to be involved in attachment to solid surfaces or to other cells, and are essential for the virulence of some bacterial pathogens. Pili (sing. pilus) are cellular appendages, slightly larger than fimbriae, that can transfer genetic material between bacterial cells in a process called conjugation where they are called conjugation pili or "sex pili" (see bacterial genetics, below). They can also generate movement where they are called type IV pili (see movement, below).


What are highly resistant dormant structures of certain gram-positive bacteria called?

Certain genera of Gram-positive bacteria, such as Bacillus, Clostridium, Sporohalobacter, Anaerobacter, and Heliobacterium, can form highly resistant, dormant structures called endospores. In almost all cases, one endospore is formed and this is not a reproductive process, although Anaerobacter can make up to seven endospores in a single cell. Endospores have a central core of cytoplasm containing DNA and ribosomes surrounded by a cortex layer and protected by an impermeable and rigid coat. Dipicolinic acid is a chemical compound that composes 5% to 15% of the dry weight of bacterial spores. It is implicated as responsible for the heat resistance of the endospore.


Is creating endospore a reproductive process?


What are ribosomes in endospores are enclosed in?


What chemical compound comprises 5% to 15% of the dry weight of bacterial spores?


Endospores show no detectable metabolism and can survive extreme physical and chemical stresses, such as high levels of UV light, gamma radiation, detergents, disinfectants, heat, freezing, pressure, and desiccation. In this dormant state, these organisms may remain viable for millions of years, and endospores even allow bacteria to survive exposure to the vacuum and radiation in space. According to scientist Dr. Steinn Sigurdsson, "There are viable bacterial spores that have been found that are 40 million years old on Earth — and we know they're very hardened to radiation." Endospore-forming bacteria can also cause disease: for example, anthrax can be contracted by the inhalation of Bacillus anthracis endospores, and contamination of deep puncture wounds with Clostridium tetani endospores causes tetanus.


What extreme physical and chemical stresses can endospores endure?


How long can endospores of bacteria stay alive in dormant state?


What endospore-forming bacteria can cause tetanus disease?


What is commonly used to determine taxonomy of bacteria?

Bacteria exhibit an extremely wide variety of metabolic types. The distribution of metabolic traits within a group of bacteria has traditionally been used to define their taxonomy, but these traits often do not correspond with modern genetic classifications. Bacterial metabolism is classified into nutritional groups on the basis of three major criteria: the kind of energy used for growth, the source of carbon, and the electron donors used for growth. An additional criterion of respiratory microorganisms are the electron acceptors used for aerobic or anaerobic respiration.


What are electron acceptors accountable for?


What are three main criterias of bacterial metabolism?


How does heterotrophic carbon metabolism occur?

Carbon metabolism in bacteria is either heterotrophic, where organic carbon compounds are used as carbon sources, or autotrophic, meaning that cellular carbon is obtained by fixing carbon dioxide. Heterotrophic bacteria include parasitic types. Typical autotrophic bacteria are phototrophic cyanobacteria, green sulfur-bacteria and some purple bacteria, but also many chemolithotrophic species, such as nitrifying or sulfur-oxidising bacteria. Energy metabolism of bacteria is either based on phototrophy, the use of light through photosynthesis, or based on chemotrophy, the use of chemical substances for energy, which are mostly oxidised at the expense of oxygen or alternative electron acceptors (aerobic/anaerobic respiration).


When carbon metabolism is called autotrophic?


What category do parasitic bacteria fall into?


Green sulfur-bacteria is typical representative of what type of bacteria?


Bacteria are further divided into lithotrophs that use inorganic electron donors and organotrophs that use organic compounds as electron donors. Chemotrophic organisms use the respective electron donors for energy conservation (by aerobic/anaerobic respiration or fermentation) and biosynthetic reactions (e.g., carbon dioxide fixation), whereas phototrophic organisms use them only for biosynthetic purposes. Respiratory organisms use chemical compounds as a source of energy by taking electrons from the reduced substrate and transferring them to a terminal electron acceptor in a redox reaction. This reaction releases energy that can be used to synthesise ATP and drive metabolism. In aerobic organisms, oxygen is used as the electron acceptor. In anaerobic organisms other inorganic compounds, such as nitrate, sulfate or carbon dioxide are used as electron acceptors. This leads to the ecologically important processes of denitrification, sulfate reduction, and acetogenesis, respectively.


What type of electron donors organotrophs use?


In what organisms is oxygen used as eelectron acceptor?


What do respiratory organisms use as electron donors?


What is sulfate-reducing bacteria accountable for?

These processes are also important in biological responses to pollution; for example, sulfate-reducing bacteria are largely responsible for the production of the highly toxic forms of mercury (methyl- and dimethylmercury) in the environment. Non-respiratory anaerobes use fermentation to generate energy and reducing power, secreting metabolic by-products (such as ethanol in brewing) as waste. Facultative anaerobes can switch between fermentation and different terminal electron acceptors depending on the environmental conditions in which they find themselves.


What is the by-product of non-repiratory anaerobes?


How can anaerobes adjust to the surrounding environment?


What are hydrogen and carbon monoxide for Lithotrophic bacteria?

Lithotrophic bacteria can use inorganic compounds as a source of energy. Common inorganic electron donors are hydrogen, carbon monoxide, ammonia (leading to nitrification), ferrous iron and other reduced metal ions, and several reduced sulfur compounds. In unusual circumstances, the gas methane can be used by methanotrophic bacteria as both a source of electrons and a substrate for carbon anabolism. In both aerobic phototrophy and chemolithotrophy, oxygen is used as a terminal electron acceptor, whereas under anaerobic conditions inorganic compounds are used instead. Most lithotrophic organisms are autotrophic, whereas organotrophic organisms are heterotrophic.


How can gas methane be used in exceptional set of conditions by methanotrophic bacteria?


What is the main element for aerobic photorophy?


What chemical process helps bacteria to absorb raw materials?

Regardless of the type of metabolic process they employ, the majority of bacteria are able to take in raw materials only in the form of relatively small molecules, which enter the cell by diffusion or through molecular channels in cell membranes. The Planctomycetes are the exception (as they are in possessing membranes around their nuclear material). It has recently been shown that Gemmata obscuriglobus is able to take in large molecules via a process that in some ways resembles endocytosis, the process used by eukaryotic cells to engulf external items.


How can bacteria obtain raw materials from the environment?


What process is used by eukaryotic cells to absorb external items?


What part of bacteria cell is used during diffusion?


How size and reproduction are linked in bacteria?

Unlike in multicellular organisms, increases in cell size (cell growth) and reproduction by cell division are tightly linked in unicellular organisms. Bacteria grow to a fixed size and then reproduce through binary fission, a form of asexual reproduction. Under optimal conditions, bacteria can grow and divide extremely rapidly, and bacterial populations can double as quickly as every 9.8 minutes. In cell division, two identical clone daughter cells are produced. Some bacteria, while still reproducing asexually, form more complex reproductive structures that help disperse the newly formed daughter cells. Examples include fruiting body formation by Myxobacteria and aerial hyphae formation by Streptomyces, or budding. Budding involves a cell forming a protrusion that breaks away and produces a daughter cell.


If the conditions are right how long does it take for bacteria to reproduce?


In what environment are bacteria being cultivated in labs?

In the laboratory, bacteria are usually grown using solid or liquid media. Solid growth media, such as agar plates, are used to isolate pure cultures of a bacterial strain. However, liquid growth media are used when measurement of growth or large volumes of cells are required. Growth in stirred liquid media occurs as an even cell suspension, making the cultures easy to divide and transfer, although isolating single bacteria from liquid media is difficult. The use of selective media (media with specific nutrients added or deficient, or with antibiotics added) can help identify specific organisms.


What can help to indentify specific bacteria?


Which environment is better to isolate a single example of bacteria strain?


Which media is preffered to grow larger volumes of bacteria?


What is the simple way of producing large volume of bacteria cells?

Most laboratory techniques for growing bacteria use high levels of nutrients to produce large amounts of cells cheaply and quickly. However, in natural environments, nutrients are limited, meaning that bacteria cannot continue to reproduce indefinitely. This nutrient limitation has led the evolution of different growth strategies (see r/K selection theory). Some organisms can grow extremely rapidly when nutrients become available, such as the formation of algal (and cyanobacterial) blooms that often occur in lakes during the summer. Other organisms have adaptations to harsh environments, such as the production of multiple antibiotics by Streptomyces that inhibit the growth of competing microorganisms. In nature, many organisms live in communities (e.g., biofilms) that may allow for increased supply of nutrients and protection from environmental stresses. These relationships can be essential for growth of a particular organism or group of organisms (syntrophy).


What caused the evolution of different growth strategies in bacteria?


What can create a subsequent increase of nutrients in natural environment?


What do algal bacteria if nutrients are available?


What is the first stage of bacteria adaptation?

Bacterial growth follows four phases. When a population of bacteria first enter a high-nutrient environment that allows growth, the cells need to adapt to their new environment. The first phase of growth is the lag phase, a period of slow growth when the cells are adapting to the high-nutrient environment and preparing for fast growth. The lag phase has high biosynthesis rates, as proteins necessary for rapid growth are produced. The second phase of growth is the log phase, also known as the logarithmic or exponential phase. The log phase is marked by rapid exponential growth. The rate at which cells grow during this phase is known as the growth rate (k), and the time it takes the cells to double is known as the generation time (g). During log phase, nutrients are metabolised at maximum speed until one of the nutrients is depleted and starts limiting growth. The third phase of growth is the stationary phase and is caused by depleted nutrients. The cells reduce their metabolic activity and consume non-essential cellular proteins. The stationary phase is a transition from rapid growth to a stress response state and there is increased expression of genes involved in DNA repair, antioxidant metabolism and nutrient transport. The final phase is the death phase where the bacteria run out of nutrients and die.


What is the second phase of bacteria growth known for?


The absence of what causes the last stage of bacteria growth?


What is called the third statge of growth of bacteria?


How many phase are in the growth of bacteria?


Most bacteria have a single circular chromosome that can range in size from only 160,000 base pairs in the endosymbiotic bacteria Candidatus Carsonella ruddii, to 12,200,000 base pairs in the soil-dwelling bacteria Sorangium cellulosum. Spirochaetes of the genus Borrelia are a notable exception to this arrangement, with bacteria such as Borrelia burgdorferi, the cause of Lyme disease, containing a single linear chromosome. The genes in bacterial genomes are usually a single continuous stretch of DNA and although several different types of introns do exist in bacteria, these are much rarer than in eukaryotes.


What bacteria is an exception to single circular chromosome rule?


What bacteria is responsible for Lyme disease?


How does chromosome of Borrelia burgdoferi look like?


What makes bacteria an asexual organism?

Bacteria, as asexual organisms, inherit identical copies of their parent's genes (i.e., they are clonal). However, all bacteria can evolve by selection on changes to their genetic material DNA caused by genetic recombination or mutations. Mutations come from errors made during the replication of DNA or from exposure to mutagens. Mutation rates vary widely among different species of bacteria and even among different clones of a single species of bacteria. Genetic changes in bacterial genomes come from either random mutation during replication or "stress-directed mutation", where genes involved in a particular growth-limiting process have an increased mutation rate.


What are two ways changes to DNA of bacteria can occur?


What is the aftermath of infrequent errors during intracellular assembly of virus particles?

Transduction of bacterial genes by bacteriophage appears to be a consequence of infrequent errors during intracellular assembly of virus particles, rather than a bacterial adaptation. Conjugation, in the much-studied E. coli system is determined by plasmid genes, and is an adaptation for transferring copies of the plasmid from one bacterial host to another. It is seldom that a conjugative plasmid integrates into the host bacterial chromosome, and subsequently transfers part of the host bacterial DNA to another bacterium. Plasmid-mediated transfer of host bacterial DNA also appears to be an accidental process rather than a bacterial adaptation.


What is the result of bacterial adaptation of E.coli bacteria host and plasmid of another bacteria?


Is conjugation a common bacterial adaptation?


What does transformation of bacteria depends on?

Transformation, unlike transduction or conjugation, depends on numerous bacterial gene products that specifically interact to perform this complex process, and thus transformation is clearly a bacterial adaptation for DNA transfer. In order for a bacterium to bind, take up and recombine donor DNA into its own chromosome, it must first enter a special physiological state termed competence (see Natural competence). In Bacillus subtilis, about 40 genes are required for the development of competence. The length of DNA transferred during B. subtilis transformation can be between a third of a chromosome up to the whole chromosome. Transformation appears to be common among bacterial species, and thus far at least 60 species are known to have the natural ability to become competent for transformation. The development of competence in nature is usually associated with stressful environmental conditions, and seems to be an adaptation for facilitating repair of DNA damage in recipient cells.


How simple is the process of transformation?


What is the first requirement in order for bacteria to bind and recombine with other bacteria's DNA


How big can be the transformation level?


How rare is the transformation among bacteria organisms?


Between what species do usually transduction, conjugation and transformation take place?

In ordinary circumstances, transduction, conjugation, and transformation involve transfer of DNA between individual bacteria of the same species, but occasionally transfer may occur between individuals of different bacterial species and this may have significant consequences, such as the transfer of antibiotic resistance. In such cases, gene acquisition from other bacteria or the environment is called horizontal gene transfer and may be common under natural conditions. Gene transfer is particularly important in antibiotic resistance as it allows the rapid transfer of resistance genes between different pathogens.


What are the consequences of transfer between different species of bacteria?


Bacteriophages are viruses that infect bacteria. Many types of bacteriophage exist, some simply infect and lyse their host bacteria, while others insert into the bacterial chromosome. A bacteriophage can contain genes that contribute to its host's phenotype: for example, in the evolution of Escherichia coli O157:H7 and Clostridium botulinum, the toxin genes in an integrated phage converted a harmless ancestral bacterium into a lethal pathogen. Bacteria resist phage infection through restriction modification systems that degrade foreign DNA, and a system that uses CRISPR sequences to retain fragments of the genomes of phage that the bacteria have come into contact with in the past, which allows them to block virus replication through a form of RNA interference. This CRISPR system provides bacteria with acquired immunity to infection.


What can happen if Bacteriophage contain genes of host's phenotype?


Bacterial species differ in the number and arrangement of flagella on their surface; some have a single flagellum (monotrichous), a flagellum at each end (amphitrichous), clusters of flagella at the poles of the cell (lophotrichous), while others have flagella distributed over the entire surface of the cell (peritrichous). The bacterial flagella is the best-understood motility structure in any organism and is made of about 20 proteins, with approximately another 30 proteins required for its regulation and assembly. The flagellum is a rotating structure driven by a reversible motor at the base that uses the electrochemical gradient across the membrane for power. This motor drives the motion of the filament, which acts as a propeller.


How many proteins is typical flagellum consist os?


When flagellum is distributed throughout the surface of the cell?


If bacteria has flagellum at each end what is the name of the species?


How does flagellum function within the cell?


How can we classify the vast variety of bacterial species?

Classification seeks to describe the diversity of bacterial species by naming and grouping organisms based on similarities. Bacteria can be classified on the basis of cell structure, cellular metabolism or on differences in cell components, such as DNA, fatty acids, pigments, antigens and quinones. While these schemes allowed the identification and classification of bacterial strains, it was unclear whether these differences represented variation between distinct species or between strains of the same species. This uncertainty was due to the lack of distinctive structures in most bacteria, as well as lateral gene transfer between unrelated species. Due to lateral gene transfer, some closely related bacteria can have very different morphologies and metabolisms. To overcome this uncertainty, modern bacterial classification emphasizes molecular systematics, using genetic techniques such as guanine cytosine ratio determination, genome-genome hybridization, as well as sequencing genes that have not undergone extensive lateral gene transfer, such as the rRNA gene. Classification of bacteria is determined by publication in the International Journal of Systematic Bacteriology, and Bergey's Manual of Systematic Bacteriology. The International Committee on Systematic Bacteriology (ICSB) maintains international rules for the naming of bacteria and taxonomic categories and for the ranking of them in the International Code of Nomenclature of Bacteria.


Can classification be helpful in determining differences between distinct species?


What supports the uncertainty in classification between the same kind of bacteria?


What can lateral gene transfer create in bacteria?


What is the way modern classification tries to determine species?


What would original term "bacteria" determine?

The term "bacteria" was traditionally applied to all microscopic, single-cell prokaryotes. However, molecular systematics showed prokaryotic life to consist of two separate domains, originally called Eubacteria and Archaebacteria, but now called Bacteria and Archaea that evolved independently from an ancient common ancestor. The archaea and eukaryotes are more closely related to each other than either is to the bacteria. These two domains, along with Eukarya, are the basis of the three-domain system, which is currently the most widely used classification system in microbiolology. However, due to the relatively recent introduction of molecular systematics and a rapid increase in the number of genome sequences that are available, bacterial classification remains a changing and expanding field. For example, a few biologists argue that the Archaea and Eukaryotes evolved from Gram-positive bacteria.


What are two main groups of prokaryotic organisms are divided into?


What groups of organisms are closely related to each other?


What domain system is commonly used nowdays to classify microorganisms?


What was developed by Hans Christian Gram?

The Gram stain, developed in 1884 by Hans Christian Gram, characterises bacteria based on the structural characteristics of their cell walls. The thick layers of peptidoglycan in the "Gram-positive" cell wall stain purple, while the thin "Gram-negative" cell wall appears pink. By combining morphology and Gram-staining, most bacteria can be classified as belonging to one of four groups (Gram-positive cocci, Gram-positive bacilli, Gram-negative cocci and Gram-negative bacilli). Some organisms are best identified by stains other than the Gram stain, particularly mycobacteria or Nocardia, which show acid-fastness on Ziehl–Neelsen or similar stains. Other organisms may need to be identified by their growth in special media, or by other techniques, such as serology.


What year was the Grahm stain was developed?


What color do Gram positive bacteria cell walls turn to after being stained?


What color is typical for Gram-negative bacteria after staining?


What stain shows better test results on Norcadia bacteria?


What technique has becoming more popular in classification of bacteria?

As with bacterial classification, identification of bacteria is increasingly using molecular methods. Diagnostics using DNA-based tools, such as polymerase chain reaction, are increasingly popular due to their specificity and speed, compared to culture-based methods. These methods also allow the detection and identification of "viable but nonculturable" cells that are metabolically active but non-dividing. However, even using these improved methods, the total number of bacterial species is not known and cannot even be estimated with any certainty. Following present classification, there are a little less than 9,300 known species of prokaryotes, which includes bacteria and archaea; but attempts to estimate the true number of bacterial diversity have ranged from 107 to 109 total species – and even these diverse estimates may be off by many orders of magnitude.


What tool does DNA based diagnostics use?


What else can molecular methods of classification reveal?


Can new methods determine a total number of bacteria species?


Why are certain bacteria called predatory?

Some species of bacteria kill and then consume other microorganisms, these species are called predatory bacteria. These include organisms such as Myxococcus xanthus, which forms swarms of cells that kill and digest any bacteria they encounter. Other bacterial predators either attach to their prey in order to digest them and absorb nutrients, such as Vampirovibrio chlorellavorus, or invade another cell and multiply inside the cytosol, such as Daptobacter. These predatory bacteria are thought to have evolved from saprophages that consumed dead microorganisms, through adaptations that allowed them to entrap and kill other organisms.


Which way do Vampirovibrio absorb nutrients of other microorganisms?


What technique do Daptobacter use in order to kill other microorganism?


Where do Daptobacter bacteria come from?


Certain bacteria form close spatial associations that are essential for their survival. One such mutualistic association, called interspecies hydrogen transfer, occurs between clusters of anaerobic bacteria that consume organic acids, such as butyric acid or propionic acid, and produce hydrogen, and methanogenic Archaea that consume hydrogen. The bacteria in this association are unable to consume the organic acids as this reaction produces hydrogen that accumulates in their surroundings. Only the intimate association with the hydrogen-consuming Archaea keeps the hydrogen concentration low enough to allow the bacteria to grow.


What kind of bacteria can form interspecies hydrogen transfer?


In soil, microorganisms that reside in the rhizosphere (a zone that includes the root surface and the soil that adheres to the root after gentle shaking) carry out nitrogen fixation, converting nitrogen gas to nitrogenous compounds. This serves to provide an easily absorbable form of nitrogen for many plants, which cannot fix nitrogen themselves. Many other bacteria are found as symbionts in humans and other organisms. For example, the presence of over 1,000 bacterial species in the normal human gut flora of the intestines can contribute to gut immunity, synthesise vitamins, such as folic acid, vitamin K and biotin, convert sugars to lactic acid (see Lactobacillus), as well as fermenting complex undigestible carbohydrates. The presence of this gut flora also inhibits the growth of potentially pathogenic bacteria (usually through competitive exclusion) and these beneficial bacteria are consequently sold as probiotic dietary supplements.


How does the conversion help the vegetation?


What is the amount of bacteria in human intestines?


How does gut flora prevent growth of pathogenic bacteria?


If bacteria form a parasitic association with other organisms, they are classed as pathogens. Pathogenic bacteria are a major cause of human death and disease and cause infections such as tetanus, typhoid fever, diphtheria, syphilis, cholera, foodborne illness, leprosy and tuberculosis. A pathogenic cause for a known medical disease may only be discovered many years after, as was the case with Helicobacter pylori and peptic ulcer disease. Bacterial diseases are also important in agriculture, with bacteria causing leaf spot, fire blight and wilts in plants, as well as Johne's disease, mastitis, salmonella and anthrax in farm animals.


Can cause for most pathogenic diseases be found soon?


How pathogenes interact with it's human host?

Each species of pathogen has a characteristic spectrum of interactions with its human hosts. Some organisms, such as Staphylococcus or Streptococcus, can cause skin infections, pneumonia, meningitis and even overwhelming sepsis, a systemic inflammatory response producing shock, massive vasodilation and death. Yet these organisms are also part of the normal human flora and usually exist on the skin or in the nose without causing any disease at all. Other organisms invariably cause disease in humans, such as the Rickettsia, which are obligate intracellular parasites able to grow and reproduce only within the cells of other organisms. One species of Rickettsia causes typhus, while another causes Rocky Mountain spotted fever. Chlamydia, another phylum of obligate intracellular parasites, contains species that can cause pneumonia, or urinary tract infection and may be involved in coronary heart disease. Finally, some species, such as Pseudomonas aeruginosa, Burkholderia cenocepacia, and Mycobacterium avium, are opportunistic pathogens and cause disease mainly in people suffering from immunosuppression or cystic fibrosis.


Can all bacteria in human body be harmful?


Which bacteria cause Rocky Mountain spotted fever disiease?


What type of antibiotics called bacterocidal?

Bacterial infections may be treated with antibiotics, which are classified as bacteriocidal if they kill bacteria, or bacteriostatic if they just prevent bacterial growth. There are many types of antibiotics and each class inhibits a process that is different in the pathogen from that found in the host. An example of how antibiotics produce selective toxicity are chloramphenicol and puromycin, which inhibit the bacterial ribosome, but not the structurally different eukaryotic ribosome. Antibiotics are used both in treating human disease and in intensive farming to promote animal growth, where they may be contributing to the rapid development of antibiotic resistance in bacterial populations. Infections can be prevented by antiseptic measures such as sterilizing the skin prior to piercing it with the needle of a syringe, and by proper care of indwelling catheters. Surgical and dental instruments are also sterilized to prevent contamination by bacteria. Disinfectants such as bleach are used to kill bacteria or other pathogens on surfaces to prevent contamination and further reduce the risk of infection.


What kind of antibiotics are used for prevention of bacterial growth


What is the drawback of using antibiotics if agriculture?


Besides in treating human disease where else are antibiotics used?


What is common prevention method of infections in medicine?


What quality of bacteria is being widely used re-cyling?

The ability of bacteria to degrade a variety of organic compounds is remarkable and has been used in waste processing and bioremediation. Bacteria capable of digesting the hydrocarbons in petroleum are often used to clean up oil spills. Fertilizer was added to some of the beaches in Prince William Sound in an attempt to promote the growth of these naturally occurring bacteria after the 1989 Exxon Valdez oil spill. These efforts were effective on beaches that were not too thickly covered in oil. Bacteria are also used for the bioremediation of industrial toxic wastes. In the chemical industry, bacteria are most important in the production of enantiomerically pure chemicals for use as pharmaceuticals or agrichemicals.


What is being used in cleaning up oil spills?


What other way is bacteria aiding to nature?


Because of their ability to quickly grow and the relative ease with which they can be manipulated, bacteria are the workhorses for the fields of molecular biology, genetics and biochemistry. By making mutations in bacterial DNA and examining the resulting phenotypes, scientists can determine the function of genes, enzymes and metabolic pathways in bacteria, then apply this knowledge to more complex organisms. This aim of understanding the biochemistry of a cell reaches its most complex expression in the synthesis of huge amounts of enzyme kinetic and gene expression data into mathematical models of entire organisms. This is achievable in some well-studied bacteria, with models of Escherichia coli metabolism now being produced and tested. This understanding of bacterial metabolism and genetics allows the use of biotechnology to bioengineer bacteria for the production of therapeutic proteins, such as insulin, growth factors, or antibodies.


When was the first time bacteria were observed?

Bacteria were first observed by the Dutch microscopist Antonie van Leeuwenhoek in 1676, using a single-lens microscope of his own design. He then published his observations in a series of letters to the Royal Society of London. Bacteria were Leeuwenhoek's most remarkable microscopic discovery. They were just at the limit of what his simple lenses could make out and, in one of the most striking hiatuses in the history of science, no one else would see them again for over a century. Only then were his by-then-largely-forgotten observations of bacteria — as opposed to his famous "animalcules" (spermatozoa) — taken seriously.


How long did it take for his discovery to be taken seriously?


When was the first antibiotic discovered?

Though it was known in the nineteenth century that bacteria are the cause of many diseases, no effective antibacterial treatments were available. In 1910, Paul Ehrlich developed the first antibiotic, by changing dyes that selectively stained Treponema pallidum — the spirochaete that causes syphilis — into compounds that selectively killed the pathogen. Ehrlich had been awarded a 1908 Nobel Prize for his work on immunology, and pioneered the use of stains to detect and identify bacteria, with his work being the basis of the Gram stain and the Ziehl–Neelsen stain.


Who based their research on Enrlich's stains works?


What's the abbreviation for a printed wiring board?

When the board has no embedded components it is more correctly called a printed wiring board (PWB) or etched wiring board. However, the term printed wiring board has fallen into disuse. A PCB populated with electronic components is called a printed circuit assembly (PCA), printed circuit board assembly or PCB assembly (PCBA). The IPC preferred term for assembled boards is circuit card assembly (CCA), and for assembled backplanes it is backplane assemblies. The term PCB is used informally both for bare and assembled boards.


What organization likes the term "circuit card assembly" for boards that have already been assembled?


What would we call a printed circuit board with embedded electronics, abbreviated PCA?


What's the more appropriate, but mostly unused, name for a printed circuit board when it doesn't have embedded components?


What abbreviation would the IPC use for an assembled circuit board?


In the old PCB design method, what was used to connect component pin pads?

Initially PCBs were designed manually by creating a photomask on a clear mylar sheet, usually at two or four times the true size. Starting from the schematic diagram the component pin pads were laid out on the mylar and then traces were routed to connect the pads. Rub-on dry transfers of common component footprints increased efficiency. Traces were made with self-adhesive tape. Pre-printed non-reproducing grids on the mylar assisted in layout. To fabricate the board, the finished photomask was photolithographically reproduced onto a photoresist coating on the blank copper-clad boards.


What did PCB designers used to employ on a mylar sheet?


What were traces originally made out of?


Designers would rub on a dry transfer of what to make the process of laying out components simpler?


What kind of metal coated the blank boards used to make PCBs?


What process groups PCBs before transfer to a panel?

Panelization is a procedure whereby a number of PCBs are grouped for manufacturing onto a larger board - the panel. Usually a panel consists of a single design but sometimes multiple designs are mixed on a single panel. There are two types of panels: assembly panels - often called arrays - and bare board manufacturing panels. The assemblers often mount components on panels rather than single PCBs because this is efficient. The bare board manufactures always uses panels, not only for efficiency, but because of the requirements the plating process. Thus a manufacturing panel can consist of a grouping of individual PCBs or of arrays, depending on what must be delivered.


Is it more common for panels to have a single design or many designs?


What type of panels can also be referred to as an "array?'


What step of the bare board manufacture would be impossible if panels weren't always used?


Besides assembly panels, what's the other type of panel?