Vil man fra en aminosyresekvens konstruere det tilhørende RNA eller DNA er Skal man aflæse en DNA-kode, er tabellen s i Det Levendes Kemi bedst. Her siges det, at faget er en blanding af Biologi B og Kemi B. Faget fokuserer på anvendes biologiske systemer, levende organismer, eller afledninger deraf. retninger; således fordybede han sig grundig i kemi ved Den polytekniske Læreanstalt. Det blev dog fornemmelig Paris, der fængslede ham. Han måtte bort fra det døde og til det levende, fra teori til praksis, og dette lykkedes ham, da .

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It goes into the upper atmosphere.

But it becomes oxygen rich enough that at least the environment becomes suitable for eurkaryotic organisms or eukaryotic cells. Anything on the land would have just gotten irradiated. And we are eukaryotes. The land was just open to it. Although there’s some debate here.

And “proterozoic” comes from the Greek for earlier life. But it’s even more violet than purple. The estimates are 50 to trillion eukaryotic cells.

C.E. Fenger – Wikipedia, den frie encyklopædi

So this kind of sets the stage for in the next eon, for animals or living things, to eventually get on to the land. Video udskrift We left off in the last video in the Archean Eon. And “UV” stands for ultraviolet. So what happened, and what I guess has dett happen, and the reason why we are able to live on land now is that we dett an ozone layer. We needed this to happen. And Proterozoic Eon, it’s right over here.

So here is the ocean and then here is the land. Most eukaryotes have other organelles, like mitochondria.


And so the only life at this point could occur in the ocean, where it was protected to some degree from the ultraviolet radiation. So as we go through the Proterozoic Eon, I guess the big markers of it is it’s the first time that we now have an oxygen-rich atmosphere.

Now, the other really interesting thing that happened in the Archean Eon, and it really has pretty profound effects once we get into the Proterozoic Eon, is that you started to have cyanobacteria produce levenees. And we’ll talk about that in the next video.

The human body, we’re not just one eukaryotic cell. They marked it this right here, 2. So we are able to find rocks that we can date jemi be roughly 3. I don’t know if you can see it. I mean the current theory is that mitochondria is actually descended from kind of an ancient prokaryotic cell, an ancient bacteria. So I’m drawing it in purple.

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It eventually saturates the iron. And I’ll do history with a capital H, in the history of the Earth. And this is right here. I’m sure that number will be refined. And that happened because we weren’t able to retain our heat, if that theory is correct.

So we’re now in this time period right over here. And actually, your mitochondrial DNA is passed down from your mother, and your mother’s mother, and your mother’s mother, so on and so forth. For at logge ind og bruge alle funktionerne i Khan Academy, skal du aktivere JavaScript i din browser.

But what happens is we enter into the Proterozoic Eon. It just would not be able to live. Oxygen accumulates in the atmosphere. So it’s constantly being bombarded by with ultraviolet radiation from the Sun, which is very inhospitable to DNA and to life. It means beginning or origin. And it’s the eon in which either life first started to exist or at least it first start to somewhat flourish. And I’m not a Greek scholar.


The first is is that it became suitable now for eukaryotes to exist. So this right over here, 2. And it’s also crucial because eukaryotic organisms need that oxygen.

And, of course, these dates, they might be moved around a few hundred million years as we get more and more data. Now, the third thing that happened, and this is also pretty significant event, we believe that that oxygen that started to accumulate in the atmosphere, reacted with methane in the atmosphere.

And once it reacts with the oxygen and starts dropping out of the atmosphere as methane, we believe the Earth cooled down. So the oxygen starts to get released and accumulate in the atmosphere. We’re now in the Proterozoic Eon that starts up about 2. But give or take a few ddt millions of years, one prokaryote got engulfed by another prokaryote, and said, hey, we do pretty well living together. It’s poisonous to most of the other organisms on the planet that were anaerobic, that did not need oxygen, that actually found oxygen poisonous.

It’s DNA would get mutated.