Nitrogen Cycle

by Jason Amores Sumpter
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nitrogen is an essential nutrient toe living organisms, and the reason for this is it's a required element in both nuclear acids and proteins. So pretty much the basics need this stuff. And for us animals, we just have to eat something that has nitrogen in it, done deal and a story plants don't have. It is easy, though. They have to obtain their nitrogen through some more complex means. Now. Nitrogen actually cycles through ecosystems in a very creatively termed chemical cycle called the nitrogen cycle, and in this process, nitrogen is actually converted through a variety of chemical forms. The most abundant form that plants will see nitrogen in is and two in the atmosphere, this atmospheric, gaseous nitrogen. It's actually almost 80% of the atmosphere. It's technically, it's about 78%. We'll just call it 80. Keep it nice and even or nice round numbers. Um, thing is, plants can't absorb this nitrogen sucks for them. They can't absorb this gashes, and two, they actually are going to rely on this process that bacteria and archaea will carry out called nitrogen fixation, which is the conversion of that gashes end to into this usable NH three ammonia form of nitrogen. Now plants are actually going to absorb mostly ammonium right, which is the protein ated form of this. Um, you know, ammonia is a weak base, so you know, after it's chemically converted, it's gonna pick up a proton turned into ammonium, most likely, and they also will absorb these nitrates, which will come as a product of various downstream reactions after the bacteria and archaea convert the a gaseous nitrogen into ammonia. So these were the two main forms absorbed by plants. But it's important to note that not every plant is going to rely on this process. In fact, carnivorous plants, for example, use carnivorous to supplement their nitrogen intake. Yeah, I mean, if you ever wondered, why do plants which make their own food right plants make their own sugar? Why would they need to eat these other organisms? Well, it's actually it's not to gain, uh, nutrition Thio. You know, uh, burn in the sense that sugar is used. It's actually to obtain more nitrogen. That's why they eat animals, right? Animals that are made up of meat and therefore have bunch of nitrogen in them. Now, some plants like EP if ICTs actually don't contact soil it all. They have toe live on other plants, and they actually absorb all their water and nutrients from the air, the rain and just like the debris that surround them. So it's important to remember that, you know, life has so much variety. There's always going to be exceptions. But nitrogen fixation in a large part is what plants are going thio rely on in order to obtain their nitrogen. You can see this nice chart here shows how nitrogen cycles through ecosystems in the course of the nitrogen cycle, and you might notice that decompose er's right D composers actually also contribute to night to the ammonium. In fact, de composers will also provide some sources of nitrogen to plants. Talk a little bit more about that later. Now this process. This nitrogen fixation is super energy intensive, and that's why so few species exist that can carry this out. It's really just confined to you. You know, some species of bacteria and archaea. It za really energy intensive process. It's mainly facilitated by this multi enzyme complex called nitrogenous. Another creative name for you in this complex is going to reduce caches nitrogen into ammonia, so it basically facilitates nitrogen fixation. Now, as I said, this process is extremely energy intensive. And in fact, to convert one just one molecule. I don't mean one more one molecule of and two into two molecules of NH three. Um, and that that's just for chemical balancing their right. We have to nitrogen. So we're gonna need two of these pneumonias to have our, uh, chemistry balance out. We have our balanced equation under here. If you're curious. Don't worry about memorizing it, though. Um so to convert just that one molecule of gaseous nitrogen into two molecules of pneumonia requires eight high energy electrons and a whopping 16 ATP you can see behind my head there. So this is a massively energy intensive process, especially when you consider that these guys, they're not just converting one molecule. They're going to be converting tons and tons of molecules into ammonia, making it usable to plants. So a lot of energy required. Fortunately, they can lean on plants a little bit to get some of that energy. We'll talk about that when we flip the page