Proteins are complicated chemicals made of long chains of amino acids, the tiny chemical building blocks of life.

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"The early Earth could well have been seeded with the chemical building blocks you need for life to start, " said Dr. Smith.

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Despite the excitement over achieving one of the mission's main goals, it has yet to find complex organic molecules considered the chemical building blocks of life.

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Astrobiologists like the idea that life can be built with a completely different set of chemical building blocks because it means that life could then exist in all sorts of places that Earth-based living things would find intolerable.

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And every option has to be ruled out before the researchers will acknowledge that these vital chemical building-blocks might be "indigenous" or home grown and therefore open a door to the possibility of life on Mars.

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The fungus uses a common carbohydrate processing enzyme called acetyl co-A to form the building blocks of hydrocarbons--but its unique chemical pathways are not yet understood nor is the process by which the gases escape the fungal membrane into the air.

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As this ring moves along the rod, it picks chemical units and assembles them into chains, just as ribosomes join up the building blocks of proteins.

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