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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We’re now in the Proterozoic Eon that starts up about 2. And we said in the last video that they were producing oxygen, but most of that oxygen was being absorbed by iron in the oceans. And it’s not deet oxygen rich as our current atmosphere. Although there’s some debate here.

But this is the current understanding of when things happened. It actually really reacts dett the UV light to turn into ozone, which then can help actually block the UV light.

Organisk kemi by charlotte Rosenvinge on Prezi

They marked it this right here, 2. And once it reacts with the oxygen and starts dropping out of the atmosphere as methane, we believe the Earth cooled down. So it reacted with methane. But since we have oxygen, there’s two interesting things that happened once that oxygen accumulated, other than causing this mass extinction event– actually three interesting things. So we’re now in this time period right over here.


So we are able to find rocks that we can date to be roughly 3. And I’m not a Greek scholar. And “arche” comes from ancient Greek. So this right over here, 2. The estimates are 50 to trillion eukaryotic cells. I’ll rewrite it, Proterozoic. And based on the fossil records, and when we look at how the DNA has changed over time– and we’ll do multiple videos of that– we think that the first eukaryotes showed up about 2.

And we are eukaryotes. But this, as far as I can tell, is our best current understanding. I don’t know if you can see it.

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So if you’re on the land– let me draw the land and the ocean. And we’ll talk llevendes that in the next video. It’s a greenhouse gas.

So this oxygen production, it’s crucial, one, to having an ozone layer so that eventually life can exist on the land. We’re made up of trillions. So this kind of sets the stage for in the next eon, for animals or living things, to eventually get on to the land. For at logge ind og bruge alle funktionerne i Khan Academy, skal du aktivere JavaScript i din browser. And it’s the eon in which either life first started to exist or at least it first start to somewhat flourish.


We actually talk about respiration that occurs in the mitochondria. So any of you Greeks out there, forgive me if I’m not getting the translation exactly right. 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 oxygen.

It eventually saturates the iron. 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. It’s DNA would get mutated.

And once again, all of this is happening inside of the oceans. And Proterozoic Eon, it’s right over here. We have an ozone layer up in the upper atmosphere that helps absorb, that blocks most of the UV radiation from the Sun.

But it becomes oxygen rich enough that at least the environment becomes suitable for eurkaryotic organisms or eukaryotic cells. Now, the other interesting thing that happened– remember, we’re being bombarded with UV radiation from the Sun.