ShmoopTube

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Here's your shmoop du jour, brought to you by gene material.

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Denim, actually.

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The first genetic material was likely... what?

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And here are the potential answers...

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Ok, so to determine which of the answer choices was the "first" genetic material, let's look

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at the molecules in our answer choices...

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DNA, RNA, proteins, an RNA-DNA hybrid molecule?

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Well, we know the hybrid probably cuts down on fuel emissions... but we're not really

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concerned with how "green" it is...

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The theory about how life evolved on earth tells us that the first molecules were self-sufficient

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because the earth wasn't "made" for us organisms...

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and that they were relatively simple because there was nothing else to rely on at first.

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Then as successful adaptations were developed due to the changing environment, these molecules

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grew more and more complex.

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It's how evolution works.

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So the "first molecule" we want to find is the one that's the most self-sufficient and simple.

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RNA stands for Ribonucleic acid.

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It serves several functions in creating proteins for living cells...

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It can act as a messenger to carry copies of genetic material...

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...transfer amino acids to make proteins, and even self-replicate.

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We'd say that's pretty self-sufficient.

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We've also heard all about DNA when watching CSI...

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and how it carries all of our genetic material...

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and how we should never leave our DNA anywhere if we want to get away with some horrific crime.

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DNA is a molecule that stands for Deoxy-ribonucleic acid....

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which basically differentiates itself from RNA by having a different sugar base...

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Deoxyribose instead of ribose.

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Hence the difference between the D and R.

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But as a piece of genetic material, it only contains the genetic blueprint.

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Unlike RNA, it can't self-replicate or create proteins without RNA. So... not too self-sufficient.

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Think about C. Proteins?

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Well they're needed to interpret genetic information, but they're also the

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product of the transformation from DNA to RNA.

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So they can't be the first.

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Finally, an RNA-DNA hybrid molecule would be nice as the first piece of genetic material...

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but based on what we know about RNA, RNA doesn't really need DNA to function on its own.

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RNA by itself is simpler...

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So RNA is our first genetic material.

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Answer's B.

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Did you fill in that bubble all by yourself?

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NOW who's self-sufficient?

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