Arsenic-based lifeform, from XKCD webcomic. Click to go there.

The world has been all a-twitter with NASA’s news of a new life-form discovery. Putting ‘NASA‘ and ‘life-form‘ together in one sentence seems to have got a lot of people worked up that they have discovered life on other planets and that the invaders are coming, but really it’s all a bit closer to home and rather tamer.

GFAJ-1 bacteria - from NASA (link)

Closer to home, maybe, but still really interesting. These bacteria from Mono Lake in California are able (with a lot of lab-based prodding*) to use arsenic in place of phosphates to build the backbone of their DNA molecules. An interesting link to DNA structure there, and news-worthy in that this species has been able to substitute one fundamental element of living organisms for another, usually more toxic, molecule.

As always, for the best possible write-up of this primary research in the news, head on over to NotExactlyRocketScience. You can also read the original release from NASA.

IB Biology curriculum links:

• 3.3 DNA Structure (and AHL 7.1 here)
• 3.1 Chemical Elements and Water
• 2.2 Prokaryotes
• 2.1 Cell Theory (calculate the magnification)

Helpfully, TED has put together a playlist of related talks to put the discovery, and the search for ET, in perspective. Here’s one from Penelope Boston:

“Life on Mars? Let’s look in the caves.”

Live long and prosper.

*this clause is an edit to clarify.