Questão 65 - USP FUVEST - Simulado Oficial - 1ª Fase (2ª edição) 2027

Molecules in hot springs such as Yellowstone's Grand Prismatic
Spring could have been a source of early life.¬(Frank Kovalchek).

 

    When a bone grows, our bodies’ proteins help provide the structure. When a muscle tears, proteins help rebuild it. When we fight an infection, transport oxygen in our blood or send messages to a cell, proteins often step up to the plate. But how did these skilled molecules first form on Earth and help give rise to life?

    The mystery, which has evaded scientists for more than five decades, can be explained with rather simple chemistry, according to a study published in Nature.

    In lab experiments, scientists have successfully shown how two basic ingredients of life — ribonucleic acid (RNA) and amino acids — can combine to start protein synthesis.

    The basic ingredients and conditions — in water — are thought to have been around on Earth about 4 billion years ago, providing clues to how early life may have been kickstarted or could arise on other planets.

    “It seems pretty probable” that this reaction would have been occurring on early Earth, said Matthew Powner, a chemist at University College London and an author of the new study.

    Powner’s lab investigates the chemical processes that lead to life, exploring key mechanisms seen in all living organisms. One of the most fundamental processes is how cells make proteins, the complex molecules responsible for our growth and survival from bone formation to immune support.

    Proteins are made of amino acids, which are thought to have been around long before life emerged. Proteins can’t replicate themselves and are built from blueprints, provided by nucleic acids like DNA and RNA, that instruct the amino acids to assemble.

The Washington Post.27 August 2025. Adaptado.

Considerado o contexto, a expressão idiomática “step up to the plate” (1º parágrafo) tem como efeito