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58.062 questões encontradas. Mostrando a página 2585 de 2904.
50016D60-B0 Com as alterações ambientais provocadas pela espécie humana, tem-se verificado uma redução nas populações de diversos anfíbios anuros no mundo todo. Esse fato, aliado ao pouco conhecimento que se tem da história natural de muitas espécies, torna o problema ainda mais grave.Levando em conta as características biológicas e ecológicas dos anuros, considere as afirmativas a seguir.I. Enquanto estão na forma larval, eles são afetados por águas poluídas porque respiram por meio de pulmões.II. O epitélio pouco queratinizado torna os adultos mais suscetíveis à desidratação quando a cobertura vegetal é reduzida.III. A poluição do ar prejudica os anuros porque eles possuem respiração cutânea mais desenvolvida que a pulmonar.IV. Por serem sensíveis à poluição, os anuros são considerados indicadores biológicos da qualidade ambiental.Assinale a alternativa correta.4FFE746F-B0 Biologia
Anelídeos e MoluscosUEL · 2010MédioEntre para guardar nos favoritosÉ comum, quando pessoas entram em lagoas do Pantanal, anelídeos sanguessugas se fixarem na pele para se alimentarem. Para isso, utilizam uma ventosa oral que possui pequenos dentes afiados que raspam a pele, provocando hemorragia.Com relação às sanguessugas, considere as afirmativas a seguir.I. Contêm um par de nefrídio individualizado para cada segmento corporal.II. São celomados com inúmeros segmentos iguais separados internamente por septos transversais membranosos.III. Da mesma forma que as minhocas, as sanguessugas apresentam cerdas para a locomoção.IV. Assim como nas minhocas, os órgãos são irrigados por uma rede contínua de capilares que se estende sob a epiderme.Assinale a alternativa correta.4FFA2D77-B0 Biologia
Principais doenças endêmicas no BrasilUEL · 2010DifícilEntre para guardar nos favoritosUma das medidas mais eficientes de combate à dengue é a eliminação de águas paradas, onde podem proliferar as larvas dos mosquitos Aedes aegypti.Com base no enunciado, pode-se concluir que o Aedes agypti é uma espécie de inseto que tem seu desenvolvimento biológico do tipo:4FF46740-B0 Biologia
Identidade dos seres vivosUEL · 2010DifícilEntre para guardar nos favoritosConsidere o experimento sobre o efeito inibidor de hormônio vegetal no desenvolvimento das gemas laterais, apresentado na figura a seguir.
Com base na figura e nos conhecimentos sobre fisiologia vegetal, considere as afirmativas a seguir.I. A ausência de hormônio produzido pelo meristema apical do caule exerce inibição sobre as gemas laterais, mantendo-as em estado de dormência.II. As gemas laterais da planta-controle estão inibidas devido ao efeito do hormônio produzido pela gema apical.III. O hormônio aplicado na planta decapitada inibe as gemas laterais e, consequentemente, a formação de ramos laterais.IV. A técnica de poda das gemas apicais tem como objetivo estimular a formação de novos ramos laterais.Assinale a alternativa correta.4FE87A45-B0 Biologia
FotossínteseUEL · 2010DifícilEntre para guardar nos favoritosA figura a seguir é uma fotomicrografia ao microscópio óptico de estômato de Tradescantia, em vista frontal:
Os estômatos são responsáveis pela regulação das trocas gasosas e pela transpiração nos vegetais. A concentração de CO2 e a temperatura atmosférica são fatores ambientais que influenciam no controle do mecanismo de abertura e fechamento dos estômatos.

(Adaptado de: AMABIS, J. M.; MARTHO, G. R. Biologia dos Organismos. São Paulo: Moderna. 2004. v. 2, p. 232.)
Com base na figura, no texto e nos conhecimentos sobre o processo de abertura e fechamento de estômatos, assinale a alternativa que explica corretamente as razões fisiológicas pelas quais a luz influencia neste processo.
4FE3ABF4-B0 Biologia
A herança dos grupos sanguíneosUEL · 2010MédioEntre para guardar nos favoritosUm menino tem o lobo da orelha preso e pertence a uma família na qual o pai, a mãe e a irmã possuem o lobo da orelha solto. Esta diferença não o incomodava até começar a estudar genética e aprender que o lobo da orelha solto é um caráter controlado por um gene com dominância completa. Aprendeu também que os grupos sanguíneos, do sistema ABO, são determinados pelos alelos IA, I B e i. Querendo saber se era ou não filho biológico deste casal, buscou informações acerca dos tipos sanguíneos de cada um da família. Ele verificou que a mãe e a irmã pertencem ao grupo sanguíneo O e o pai, ao grupo AB.Com base no enunciado é correto afirmar que4FDFD9E1-B0 Biologia
Moléculas, células e tecidosUEL · 2010MédioEntre para guardar nos favoritosEm uma população, foi identificado um indivíduo que possui resistência genética a um vírus que provoca uma importante doença. Em um estudo comparativo, verificou-se que esse indivíduo produz uma proteína que confere tal resistência, com a seguinte sequência de aminoácidos: serina-tirosina-cisteína-valina-arginina.A partir da tabela de código genético, a seguir:AGU - serina AGC - serinaUAC - tirosina UAU - tirosinaUGC - cisteína UGU - cisteínaGUA - valina GUU - valinaAGG - arginina CGA - arginina
e considerando que o RNA mensageiro deste gene contém: 46,7% de uracila; 33,3% de guanina; 20% de adenina e 0% de citosina, assinale a alternativa que apresenta a sequência correta de bases da fita-molde deste gene.4FDC42AA-B0 Biologia
Moléculas, células e tecidosUEL · 2010DifícilEntre para guardar nos favoritosEm 1953, James Watson e Francis Crick elucidaram a estrutura tridimensional da dupla hélice de DNA e postularam que o pareamento específico de bases nitrogenadas sugere um possível mecanismo de cópia para o material genético. Baseado neste postulado, o processo de duplicação do DNA é considerado como sendo semiconservativo porque:4FD85679-B0 Biologia
Ciclo CelularUEL · 2010DifícilEntre para guardar nos favoritosO processo de mitose é essencial para o desenvolvimento e o crescimento de todos os organismos eucariotos.

(KLUG, Willian et al. Conceitos de Genética. 9. ed. Porto Alegre: Artmed, 2010. p. 24.)
Com base na figura e nos conhecimentos sobre o ciclo celular, é correto afirmar:
C03EFC1A-B0 Inglês
Interpretação de texto | Reading comprehensionUFPR · 2010MédioEntre para guardar nos favoritosGermans make wonderful beer. Yet the productivity of the German beer industry is only 43 percent that of the U.S. beer industry. Meanwhile, the German metalworking and steel industries are equal in productivity to their American counterparts. Since the Germans are evidently capable of organizing industries well, why can’t they do so when it comes to beer?It turns out that the German beer industry suffers from small-scale production. There are a thousand tiny beer companies in Germany, shielded from competition with one another because each German brewery has virtually a local monopoly, and they are also shielded from competition with imports. The United States has 67 major beer breweries, producing 23 billion liters of beer per year. All of Germany’s 1,000 breweries combined produce only half as much. Thus the average U.S. brewery produces 31 times more beer than the average German brewery.This fact results from local tastes and German government policies. German beer drinkers are fiercely loyal to their local brand, so there are no national brands in Germany analogous to our Budweiser, Miller, or Coors. Instead, most German beer is consumed within 30 miles of the factory where it is brewed. Therefore, the German beer industry cannot profit from economies of scale. In the beer business, as in other businesses, production costs decrease greatly with scale. The bigger the refrigerating unit for making beer, and the longer the assembly line for filling bottles with beer, the lower the cost of manufacturing beer. Those tiny German beer companies are relatively inefficient. There’s no competition; there are just a thousand local monopolies.The local beer loyalties of individual German drinkers are reinforced by German laws that make it hard for foreign beers to compete in the German market. The German government has so-called beer purity laws that specify exactly what can go into beer. Not surprisingly, those government purity specifications are based on what German breweries put into beer, and not what American, French, and Swedish breweries like to put into beer. Because of those laws, not much foreign beer gets exported to Germany, and because of inefficiency and high prices much less of that wonderful German beer than you would otherwise expect gets sold abroad. (Before you object that German Löwenbräu beer is widely available in the United States, please read the label on the next bottle of Löwenbräu that you drink here: it’s not produced in Germany but in North America, under license, in big factories with North American productivities and efficiencies of scale).(Diamond, J. ,2005. Guns, Germs, and Steel. New York: Norton.)
According to the text, why does Germany export so little beer to the U.S.?C03B2772-B0 Inglês
Interpretação de texto | Reading comprehensionUFPR · 2010FácilEntre para guardar nos favoritosGermans make wonderful beer. Yet the productivity of the German beer industry is only 43 percent that of the U.S. beer industry. Meanwhile, the German metalworking and steel industries are equal in productivity to their American counterparts. Since the Germans are evidently capable of organizing industries well, why can’t they do so when it comes to beer?It turns out that the German beer industry suffers from small-scale production. There are a thousand tiny beer companies in Germany, shielded from competition with one another because each German brewery has virtually a local monopoly, and they are also shielded from competition with imports. The United States has 67 major beer breweries, producing 23 billion liters of beer per year. All of Germany’s 1,000 breweries combined produce only half as much. Thus the average U.S. brewery produces 31 times more beer than the average German brewery.This fact results from local tastes and German government policies. German beer drinkers are fiercely loyal to their local brand, so there are no national brands in Germany analogous to our Budweiser, Miller, or Coors. Instead, most German beer is consumed within 30 miles of the factory where it is brewed. Therefore, the German beer industry cannot profit from economies of scale. In the beer business, as in other businesses, production costs decrease greatly with scale. The bigger the refrigerating unit for making beer, and the longer the assembly line for filling bottles with beer, the lower the cost of manufacturing beer. Those tiny German beer companies are relatively inefficient. There’s no competition; there are just a thousand local monopolies.The local beer loyalties of individual German drinkers are reinforced by German laws that make it hard for foreign beers to compete in the German market. The German government has so-called beer purity laws that specify exactly what can go into beer. Not surprisingly, those government purity specifications are based on what German breweries put into beer, and not what American, French, and Swedish breweries like to put into beer. Because of those laws, not much foreign beer gets exported to Germany, and because of inefficiency and high prices much less of that wonderful German beer than you would otherwise expect gets sold abroad. (Before you object that German Löwenbräu beer is widely available in the United States, please read the label on the next bottle of Löwenbräu that you drink here: it’s not produced in Germany but in North America, under license, in big factories with North American productivities and efficiencies of scale).(Diamond, J. ,2005. Guns, Germs, and Steel. New York: Norton.)
How does Germany protect its beer industry, according to the text?C0376C7F-B0 Inglês
Interpretação de texto | Reading comprehensionUFPR · 2010FácilEntre para guardar nos favoritosGermans make wonderful beer. Yet the productivity of the German beer industry is only 43 percent that of the U.S. beer industry. Meanwhile, the German metalworking and steel industries are equal in productivity to their American counterparts. Since the Germans are evidently capable of organizing industries well, why can’t they do so when it comes to beer?It turns out that the German beer industry suffers from small-scale production. There are a thousand tiny beer companies in Germany, shielded from competition with one another because each German brewery has virtually a local monopoly, and they are also shielded from competition with imports. The United States has 67 major beer breweries, producing 23 billion liters of beer per year. All of Germany’s 1,000 breweries combined produce only half as much. Thus the average U.S. brewery produces 31 times more beer than the average German brewery.This fact results from local tastes and German government policies. German beer drinkers are fiercely loyal to their local brand, so there are no national brands in Germany analogous to our Budweiser, Miller, or Coors. Instead, most German beer is consumed within 30 miles of the factory where it is brewed. Therefore, the German beer industry cannot profit from economies of scale. In the beer business, as in other businesses, production costs decrease greatly with scale. The bigger the refrigerating unit for making beer, and the longer the assembly line for filling bottles with beer, the lower the cost of manufacturing beer. Those tiny German beer companies are relatively inefficient. There’s no competition; there are just a thousand local monopolies.The local beer loyalties of individual German drinkers are reinforced by German laws that make it hard for foreign beers to compete in the German market. The German government has so-called beer purity laws that specify exactly what can go into beer. Not surprisingly, those government purity specifications are based on what German breweries put into beer, and not what American, French, and Swedish breweries like to put into beer. Because of those laws, not much foreign beer gets exported to Germany, and because of inefficiency and high prices much less of that wonderful German beer than you would otherwise expect gets sold abroad. (Before you object that German Löwenbräu beer is widely available in the United States, please read the label on the next bottle of Löwenbräu that you drink here: it’s not produced in Germany but in North America, under license, in big factories with North American productivities and efficiencies of scale).(Diamond, J. ,2005. Guns, Germs, and Steel. New York: Norton.)
Which of these statements DOES NOT CORRESPOND to information given in the text?C03464B3-B0 Inglês
Interpretação de texto | Reading comprehensionUFPR · 2010DifícilEntre para guardar nos favoritosGermans make wonderful beer. Yet the productivity of the German beer industry is only 43 percent that of the U.S. beer industry. Meanwhile, the German metalworking and steel industries are equal in productivity to their American counterparts. Since the Germans are evidently capable of organizing industries well, why can’t they do so when it comes to beer?It turns out that the German beer industry suffers from small-scale production. There are a thousand tiny beer companies in Germany, shielded from competition with one another because each German brewery has virtually a local monopoly, and they are also shielded from competition with imports. The United States has 67 major beer breweries, producing 23 billion liters of beer per year. All of Germany’s 1,000 breweries combined produce only half as much. Thus the average U.S. brewery produces 31 times more beer than the average German brewery.This fact results from local tastes and German government policies. German beer drinkers are fiercely loyal to their local brand, so there are no national brands in Germany analogous to our Budweiser, Miller, or Coors. Instead, most German beer is consumed within 30 miles of the factory where it is brewed. Therefore, the German beer industry cannot profit from economies of scale. In the beer business, as in other businesses, production costs decrease greatly with scale. The bigger the refrigerating unit for making beer, and the longer the assembly line for filling bottles with beer, the lower the cost of manufacturing beer. Those tiny German beer companies are relatively inefficient. There’s no competition; there are just a thousand local monopolies.The local beer loyalties of individual German drinkers are reinforced by German laws that make it hard for foreign beers to compete in the German market. The German government has so-called beer purity laws that specify exactly what can go into beer. Not surprisingly, those government purity specifications are based on what German breweries put into beer, and not what American, French, and Swedish breweries like to put into beer. Because of those laws, not much foreign beer gets exported to Germany, and because of inefficiency and high prices much less of that wonderful German beer than you would otherwise expect gets sold abroad. (Before you object that German Löwenbräu beer is widely available in the United States, please read the label on the next bottle of Löwenbräu that you drink here: it’s not produced in Germany but in North America, under license, in big factories with North American productivities and efficiencies of scale).(Diamond, J. ,2005. Guns, Germs, and Steel. New York: Norton.)
Are the statements true (T) or false (F), according to the text?( ) The United States produces less beer than Germany.( ) The German steel industry is better organized than the German beer industry.( ) The German metalworking industry is more productive than the American metalworking industry.( ) In Germany there are more factories producing beer than in the United States.( ) 43% of the beer sold in the United States is produced in Germany.Mark the alternative which presents the correct sequence, from top to bottom.C0318FF4-B0 Inglês
Interpretação de texto | Reading comprehensionUFPR · 2010Muito fácilEntre para guardar nos favoritosLucy’s Big Brother Reveals New Facets of her SpeciesFirst came Lucy. Then came Lucy’s baby, an infant of her species. Now comes Lucy’s “big brother”: the partial skeleton of a large male of Australopithecus afarensis, unveiled this week in the Proceedings of the National Academy of Sciences. The roughly 40% complete skeleton has been nicknamed Kadanuumuu, which means “big man” in the Afar language of the Afar Depression of Ethiopia, where it was found. “It was huge – a big man, with long legs”, says lead author Yohannes Haile-Selassie, a palaeoanthropologist at the Cleveland Museum of Natural History in Ohio.Dated to 3.6 million years ago, the new skeleton is almost half a million years older than Lucy and the second oldest skeleton found of a possible human ancestor. It had long legs and a torso and a pelvis more like those of a modern human than an African ape, showing that fully upright walking was in place at this early date, Haile-Selassie says. Although headless, the skeleton also preserves parts not found before in Lucy’s species. “It is important because it provides the ribs and scapula”, says palaeoanthropologist Carol Ward of the University of Missouri, Columbia.In 2005, a sharp-eyed member of Haile-Selassie’s team, Alemayehu Asfaw, spotted a fragment of lower arm bone on the ground at Woranso-Mille, about 48 kilometers north of Lucy’s grave at Hadar. Over the next 4 years, the team unearthed the shoulder blade, collarbone, ribs, and neck vertebra, the first time those bones were found together in an A. afarensis adult. The team also found a pelvis, an arm, and leg bones. Although they never found the skull or teeth, which are typically used to assign species, the skeleton’s age and similarity to Lucy suggest that it belongs to her species, says co-author Owen Lovejoy of Kent State University in Ohio.The robust male stood between 1.5 and 1.7 meters tall, about 30% larger than Lucy. Isolated bones of other individuals suggest that some males were even larger, so the new skeleton doesn’t settle a long-standing debate over just how much sexual dimorphism there was in A. afarensis, Lovejoy says. The shoulder blade looks more like that of a gorilla and a modern human than that of a chimpanzee. The curvature of the second rib suggests a wide rib cage at the top and a barrel shape overall, similar to that of modern humans and distinct from the more funnel-shaped rib cage of a chimpanzee, the authors say.(Science Magazine, 25 June 2010.)Why do palaeoanthropologists believe the skeleton may be a human ancestor?C02B68AF-B0 Inglês
Interpretação de texto | Reading comprehensionUFPR · 2010FácilEntre para guardar nos favoritosLucy’s Big Brother Reveals New Facets of her SpeciesFirst came Lucy. Then came Lucy’s baby, an infant of her species. Now comes Lucy’s “big brother”: the partial skeleton of a large male of Australopithecus afarensis, unveiled this week in the Proceedings of the National Academy of Sciences. The roughly 40% complete skeleton has been nicknamed Kadanuumuu, which means “big man” in the Afar language of the Afar Depression of Ethiopia, where it was found. “It was huge – a big man, with long legs”, says lead author Yohannes Haile-Selassie, a palaeoanthropologist at the Cleveland Museum of Natural History in Ohio.Dated to 3.6 million years ago, the new skeleton is almost half a million years older than Lucy and the second oldest skeleton found of a possible human ancestor. It had long legs and a torso and a pelvis more like those of a modern human than an African ape, showing that fully upright walking was in place at this early date, Haile-Selassie says. Although headless, the skeleton also preserves parts not found before in Lucy’s species. “It is important because it provides the ribs and scapula”, says palaeoanthropologist Carol Ward of the University of Missouri, Columbia.In 2005, a sharp-eyed member of Haile-Selassie’s team, Alemayehu Asfaw, spotted a fragment of lower arm bone on the ground at Woranso-Mille, about 48 kilometers north of Lucy’s grave at Hadar. Over the next 4 years, the team unearthed the shoulder blade, collarbone, ribs, and neck vertebra, the first time those bones were found together in an A. afarensis adult. The team also found a pelvis, an arm, and leg bones. Although they never found the skull or teeth, which are typically used to assign species, the skeleton’s age and similarity to Lucy suggest that it belongs to her species, says co-author Owen Lovejoy of Kent State University in Ohio.The robust male stood between 1.5 and 1.7 meters tall, about 30% larger than Lucy. Isolated bones of other individuals suggest that some males were even larger, so the new skeleton doesn’t settle a long-standing debate over just how much sexual dimorphism there was in A. afarensis, Lovejoy says. The shoulder blade looks more like that of a gorilla and a modern human than that of a chimpanzee. The curvature of the second rib suggests a wide rib cage at the top and a barrel shape overall, similar to that of modern humans and distinct from the more funnel-shaped rib cage of a chimpanzee, the authors say.(Science Magazine, 25 June 2010.)Where was the skeleton found?C0259081-B0 Física
ÓticaUFPR · 2010DifícilEntre para guardar nos favoritosAo incidir sobre um prisma de vidro, um feixe de luz branca é decomposto em várias cores. Esse fenômeno acontece porque as ondas eletromagnéticas de diferentes comprimentos de onda se propagam no vidro com diferentes velocidades, de modo que o índice de refração n tem valor diferente para cada comprimento de onda. O estudo das propriedades óticas de um pedaço de vidro forneceu o gráfico ao lado para o índice de refração em função do comprimento de onda λ da luz. Suponha a velocidade da luz no vácuo igual a 3,0 × 108 m/s. Com base nos conceitos de ótica e nas informações do gráfico, assinale a alternativa correta.
C022C781-B0 Física
MagnetismoUFPR · 2010Muito fácilEntre para guardar nos favoritosNa segunda década do século XIX, Hans Christian Oersted demonstrou que um fio percorrido por uma corrente elétrica era capaz de causar uma perturbação na agulha de uma bússola. Mais tarde, André Marie Ampère obteve uma relação matemática para a intensidade do campo magnético produzido por uma corrente elétrica que circula em um fio condutor retilíneo. Ele mostrou que a intensidade do campo magnético depende da intensidade da corrente elétrica e da distância ao fio condutor. Com relação a esse fenômeno, assinale a alternativa correta.C01FE14C-B0 Física
EletricidadeUFPR · 2010DifícilEntre para guardar nos favoritosCapacitores são dispositivos que podem armazenar energia quando há um campo elétrico em seu interior, o qual é produzido por cargas elétricas depositadas em suas placas. O circuito ao lado é formado por um capacitor C de capacitância 2 µF e por duas fontes de fem, consideradas ideais, com ε1 = 10 V e ε2 = 15 V. Assinale a alternativa correta para a energia elétrica armazenada no capacitor C.
C01C3881-B0 Física
EletricidadeUFPR · 2010DifícilEntre para guardar nos favoritosUm pesquisador produziu um novo material e, para investigar possíveis aplicações tecnológicas, estudou o comportamento elétrico de um objeto cilíndrico feito com esse material. Aplicaram-se diversos valores de diferenças de potencial ∆V a esse objeto e mediu-se a corrente elétrica i que circulou por ele. Foi obtido então o gráfico ao lado:
Com base nesse gráfico, considere as seguintes afirmativas:1. O objeto apresenta comportamento ôhmico apenas para diferenças de potencial entre 0 V e 1 V.2. Quando submetido a uma diferença de potencial de 4 V, a resistência elétrica do objeto vale R = 20 Ω.3. Para diferenças de potencial entre 1 V e 3 V, a resistência elétrica do objeto é constante.4. Quando aplicada uma diferença de potencial de 2 V, a potência elétrica dissipada pelo objeto é igual a 1 W.Assinale a alternativa correta.C018E183-B0 Física
Oscilação e OndasUFPR · 2010DifícilEntre para guardar nos favoritosUma fila de carros, igualmente espaçados, de tamanhos e massas iguais faz a travessia de uma ponte com velocidades iguais e constantes, conforme mostra a figura abaixo. Cada vez que um carro entra na ponte, o impacto de seu peso provoca nela uma perturbação em forma de um pulso de onda. Esse pulso se propaga com velocidade de módulo 10 m/s no sentido de A para B. Como resultado, a ponte oscila, formando uma onda estacionária com 3 ventres e 4 nós. Considerando que o fluxo de carros produza na ponte uma oscilação de 1 Hz, assinale a alternativa correta para o comprimento da ponte.