Base dudow 099 2000 – Questão 38

Linguagens / Inglês / Funções Inorgânicas
    Scientists grow primitive human kidneys in a dish October 07, 2015
   For the first time, primitive human kidneys have been created in a laboratory dish, by using stem cells. Although the kidneys cannot perform the functions of a fully formed adultkidney, the researchers  hope the achievement will someday lead to new ways to treat people suffering from kidneyfailure. “It’s really exciting,” says Melissa  Little, who headsthe Kidney Research  Laboratory at the Murdoch Children’s Research Institute  in Australia. She led the research, which was published Wednesday in the journal
Nature. “I think thisis a really  big advance.”
    Kidneys are essential for life. They perform a host of crucial bodily functions, including filtering toxins from the blood and regulating blood pressure and bone density. But kidneys can fail for a variety of reasons, including poisonings, infections and other  diseases.
    “The problem is that if something goes wrong with your kidneys, there  are only two options and these have been thesame for 50 years : You either have a transplant or go ontodialysis,” Little says. “So we really need alternative options.”
To find alternatives, Little and others have been trying for years to grow kidneys in the lab using cells known as induced pluripotent stem  (iPS) cells. “Almost 10 years ago now it wasshown that  you could take any cell from anybody – like you or me – and actually convince it to go back into the state that’s essentially like the fertilized egg, so it is able to turn into any tissue type,” Little says.
  While scientists have been able to use iPS cells to create many types of human cells, using them to create a kidneyhas proved  difficult. The problem has been finding just the right combination of chemical signals to trigger iPS cells intomaking the various  tissues in a kidney. “It’s like a recipe,” Littlesays. “We put different  concentrations and types of growth factors in a certain order into  the dish. And then when it getsto a certain size  we take all the cells and make it into a ball.” After that, the cells talk to each other, she says. One type of cell will signal to its neighbor, and its neighbor will signal back,and that  actually makes them form the appropriate shape.
(www.npr.org. Adaptado.)
 
Um gel clareador dental apresenta KNO3 e NaF em sua composição. A respeito dessas substâncias, é correto afirmar que:
a) são óxidos.
b) possuem, ambas, cátion bivalente.
c) são sais solúveis em água.
d) o NaF é um composto iônico, enquanto o KNO3 é 100% molecular.
e) todas as ligações no KNO3 são iônicas, enquanto, no NaF, a ligação é covalente.
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