(CEFET PI) “O núcleo celular foi o primeiro organelo a ser descoberto, tendo sido primeiramente descrito por Franz Bauer, em 1802. Foi mais tarde descrito em mais detalhe pelo botânico escocês Robert Brown, em 1831, numa palestra na Sociedade Linneana de Londres. Brown estava a estudar orquídeas ao microscópio quando observou uma região opaca, que chamou de auréola ou núcleo, existentes nas células da camada exterior, em flores.”H Harris.  The Birth of the Cell. New Haven: Yale University Press, 1999. Sobre o núcleo interfásico analise as proposições abaixo e marque a alternativa CORRETA. 

I- É envolvido por uma simples camada fosfolipoproteica denominada de carioteca.

II- Contém o nucleoplasma que armazena uma porção arredondada rica em RNA ribossômico envolvida por uma membrana lipídica. Esta porção é denominada de nucléolo. 

III- Apresenta um complexo formado por DNA e proteínas denominado de cromatina. Uma região especial da cromatina é chamada de eucromatina, esta se apresenta menos condensada e geneticamente ativa. 

Heroism: why heroes are important

The term “hero” comes from the ancient Greeks. For

them, a hero was a mortal who had done something

so far beyond the normal scope of human experience

that he left an immortal memory behind him when

[5]  he died, and thus received worship like that due to

the gods. But people who had committed unthinkable

crimes were also called heroes. Originally, heroes

were not necessarily good, but they were always

extraordinary; to be a hero was to expand people’s

[10]  sense of what was possible for a human being.

Today, it is much harder to detach the concept of

heroism from morality; we only call heroes those whom

we admire and wish to emulate. But still the concept

retains that original link to possibility. We need heroes

[15]  first and foremost because our heroes help define the

limits of our aspirations. We largely define our ideals

by the heroes we choose, and our ideals – things like

courage, honor and justice – largely define us. Our

heroes are symbols for us of all the qualities we would

[20]  like to possess and all the ambitions we would like

to satisfy. A person who chooses Martin Luther King

as a hero is going to have a very different sense of

what human excellence involves than someone who

chooses, say, Madonna.

[25]  That is why it is so important for us as a society,

globally and locally, to try to shape these choices. Of 

course, this is a perennial moral issue, but it is clear

that the greatest obstacle to the appreciation and

adoption of heroes in our society is pervasive and

[30]  corrosive cynicism and skepticism. This obstacle of

cynicism has been seriously increased by scandals

like the steroids mess in sports competitions and by

our leaders’ opportunistic use of heroic imagery for

short term political gain.

[35]  The best antidote to this cynicism is realism about the

limits of human nature. We are cynical because so often

our ideals have been betrayed. We need to separate

out the things that make our heroes noteworthy, and

forgive the shortcomings that blemish their heroic

[40]  perfection. The false steps and frailties of heroic

people make them more like us, and since most of us

are not particularly heroic, that may seem to reduce

the heroes’ stature. But this pulls in the other direction

as well: these magnificent spirits, these noble souls,

[45]  amazingly, they are like us, they are human too.

Again, the critical moral contribution of heroes is the

expansion of our sense of possibility. Heroes can help

us lift our eyes a little higher to build more boldly

and beautifully than others, and we may all benefit

[50]  by their examples. And Heaven knows we need those

examples now. 

SCOTT LABARGE www.scu.edu 

The concept of heroism is central to human experience.

Nowadays, the choice of a hero results from:

(ENEM) “Águas de março definem se falta luz este ano”. Esse foi o título de uma reportagem em jornal de circulação nacional, pouco antes do início do racionamento do consumo de energia elétrica, em 2001. No Brasil, a relação entre a produção de eletricidade e a utilização de recursos hídricos, estabelecida nessa manchete, se justifica porque:

 Texto base: As crianças estavam brincando de cabo de guerra no pátio da escola. No início da brincadeira 12 crianças estavam participando. Algumas crianças saíram. Veja como a brincadeira ficou.   SMOLE, Kátia Stocco (Org). Brincadeiras infantis nas aulas de matemática. Porto Alegre: Artmed, 2000.

Enunciado:

1. Quantas crianças havia ao todo?

2. Faça os cálculos e descubra quantas crianças saíram da brincadeira.

3. Quantas crianças continuaram a brincar?