| 00:25 | Mhm. Okay folks, welcome Hope you had somewhere to break last |
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| 00:36 | . Um um So uh as you guess from if you flip through what |
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| 00:44 | got left, we don't have a to do today so um I'm guessing |
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| 00:50 | probably done here in about 30 minutes so. And then uh that will |
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| 00:56 | in the unit to. Okay so so of course remember you have the |
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| 01:02 | at the end of the week? What else? So we do have |
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| 01:08 | blackboard quiz um Do on sunday. will open on thursday that will |
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| 01:14 | So we're gonna start three on Wednesday chapter 21 22. Again uh just |
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| 01:23 | small portion of that's like one small bit of 21 and then a little |
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| 01:29 | of 22 That covers this kind of extension of really metabolism 14 with a |
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| 01:37 | kind of settlement, nitrogen cycle there couple other things. Um But I'm |
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| 01:43 | sure we'll be able to finish that in Wednesday's lecture. Okay And then |
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| 01:50 | go on to other things. Like rest of the material in three is |
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| 01:55 | of like I guess I called bacterial . So we'll look at that |
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| 02:02 | And then uh that will take us mid april. And then um then |
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| 02:08 | end with like medical aspects of medical uniform. So Um there's no smart |
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| 02:17 | assignments due this week. You don't to worry about that so but there |
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| 02:20 | that quiz. The quiz is only to be you know a few questions |
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| 02:22 | four or five questions. But um before then we have to finish up |
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| 02:29 | rest of 14 which basically just is we're in the photo trophy. So |
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| 02:35 | started it last time and I have couple of things up here just to |
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| 02:41 | this and it's been a while. uh so again, we're the last |
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| 02:47 | of 14 we're talking about here is Kofi Okay. Using light energy to |
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| 02:54 | metabolism, so to speak. And we look we're looking at we looked |
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| 03:00 | this process down here, the very one, the non chlorophyll based so |
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| 03:07 | can have chlorophyll based and non chlorophyll um Photo trophy. Okay, your |
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| 03:14 | is likely with the sort of with chlorophyll based. How plans allergy santa |
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| 03:21 | , how they photosynthesize disease skiing, you recall that term. Um but |
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| 03:28 | started with this uh process here, is a non chlorophyll based, so |
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| 03:34 | different. Okay, but just to of summarize a couple of things |
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| 03:38 | So we're talking about photo trophy, course we're looking we're involving a some |
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| 03:42 | of light absorbing molecules. Right? call these things photo pigments and they're |
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| 03:50 | with proteins, another accessory pigments to these light absorbing um complexes. Uh |
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| 03:59 | of course a membrane right, because do have the proton pump being generated |
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| 04:07 | so membranes essential or that we also that membrane full of these uh photo |
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| 04:14 | or photo systems are sometimes called into membrane to maximize light absorption. Um |
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| 04:22 | also have some kind of mechanism to that light energy into into into chemical |
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| 04:28 | . So in A D. H A. T. P. |
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| 04:31 | . Right? And for me that these groups your photo water trophy. |
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| 04:37 | they fixed the 02. So that because a lot of energy and it |
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| 04:42 | from the energy produced by the light . So if you recall the light |
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| 04:48 | reactions um that's what we're talking about and that the light independent those are |
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| 04:54 | ones involved in seO two fixation. . But we're not really gonna get |
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| 04:58 | co two fixation. The mechanism of . We're just going to stay focused |
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| 05:03 | the what? A light dependent Okay so uh so just to again |
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| 05:10 | so just before we talk about that full tosses reactions. So remember whereas |
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| 05:15 | three things are generally parts of any of photo trophy. Okay. Photo |
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| 05:21 | may not be okay. And so saw that was the case in um |
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| 05:27 | the non chlorophyll based system. The adoption retinal system. Okay so we |
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| 05:34 | this in uh halo archaea as well bacteria. So there's both the bacterial |
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| 05:45 | option which we've seen Archaea protium adoption similar bacterial types and both have this |
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| 05:54 | comments. So we had this protein and this molecule right now that is |
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| 06:01 | light absorbing portion. Okay so the now molecules tightly down here and light |
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| 06:12 | absorption of photons of light by the bond here. All right. Um |
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| 06:18 | of the twist to change shape. and because it's greatly bound in the |
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| 06:24 | , if the retinal flips are on they will bond and change shape. |
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| 06:28 | too does the protein changes shape as . And that shape changes accompanied by |
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| 06:35 | pumping of protons. Okay, so what so it's basically a light driven |
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| 06:40 | pump. That's what it is. a couple of features absorbs green |
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| 06:47 | Right? So it reflects blues and . And when you combine blue red |
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| 06:51 | makes purple. So there you see where this formula is growing. |
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| 06:55 | looks like a purplish mass of Okay. Um the uh other |
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| 07:03 | So the other thing basically is there's photosynthesis records some of the reactions |
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| 07:10 | Right? So here's the strictly absorption photons of light. There's no electron |
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| 07:15 | really going on here. Right, absorption of photons of life. |
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| 07:20 | And that's what causes the change And the and the pumping of |
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| 07:26 | Um the uh and so, the other thing, of course these |
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| 07:31 | photos autotrophs that do this. So remember this term hetero trophy is |
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| 07:37 | operative term. Yes, photo absorbs . Okay, uses light to make |
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| 07:42 | but it still needs a an more organic source of carbon. They |
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| 07:47 | not they don't fix don't fix the . They have to have something organic |
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| 07:54 | to metabolize chat. Um uh So we're going to talk about the rest |
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| 08:01 | the time today are really these chlorophyll systems. Okay. Um any questions |
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| 08:10 | this so far? Okay. So let's look at um your corporate |
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| 08:17 | systems. And so like I your familiarity is likely with this |
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| 08:21 | Okay, so your allergies, bacteria and plans. Right. So |
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| 08:26 | carry out the oxygen in criticism. accounts for, you know, most |
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| 08:31 | the ceo to fix in the Okay. Um oceans. Right. |
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| 08:37 | sort of the oceans and the allergy sinus bacteria that are present in the |
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| 08:41 | um and the mass, you obviously the the amount of oceans on |
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| 08:46 | earth. Right. And the amount photosynthesis that occurs as a result. |
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| 08:51 | of course, um for the census the equator, right? That's where |
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| 08:57 | light absorption is maximal maximal uh energy hitting around the equator. Okay. |
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| 09:04 | so that of course your tropical jungles things like that have lots of photosynthesis |
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| 09:08 | on. Okay. And this type photosynthesis primarily. Okay. And so |
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| 09:15 | call and oxygen IQ for the census the process produces oxygen. Right? |
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| 09:21 | all a part of that photosynthesis reaction feeds the system electron. Right? |
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| 09:27 | chlorophyll um like any of your pigment are gonna fit into a membrane. |
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| 09:35 | , there's gonna be a hydrophobic portion it. Right? So this non |
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| 09:41 | portion will stick into a membrane. . And and then allowed to fill |
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| 09:47 | that membrane with all these different photo . And so the light absorbing part |
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| 09:51 | chroma for it's called you see there these these he marine um aromatic in |
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| 09:59 | . Uh central metal atom is sitting magnesium you see there and these are |
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| 10:05 | to um unlike the previous system we about. Yeah wow this system of |
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| 10:13 | will involve transfers of electrons. so really in a nutshell is about |
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| 10:19 | life that light energy will be used knock electrons to higher energy some states |
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| 10:25 | china and then create a electron Okay, so the arrangement of these |
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| 10:34 | , so we'll have a mixture of fields and proteins, accessory pigments that |
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| 10:41 | of um expand the range of light can be absorbed. Okay, chlorophylls |
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| 10:48 | in like the blue and red Okay, so accessory pigments will kind |
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| 10:52 | expand that somewhat. And so they'll them in these uh antenna complexes, |
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| 10:59 | like they now gets to like a dish. Maybe there's a way to |
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| 11:03 | about it. And so photons of are absorbed and that energy can be |
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| 11:11 | from complex to complex basically to a center which is in the middle |
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| 11:16 | Okay. And this is what's holding pair of electrons that then once let |
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| 11:21 | red quick amount of energy is Then those are knocked out. Okay |
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| 11:26 | that's where they were then transferred to series of electronic transfer components. Um |
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| 11:32 | in terms of again mentioning that they stuff these these things into membranes to |
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| 11:38 | the density and and lots of light . The membrane itself will fold extensively |
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| 11:46 | these what we call Thailand chords. . So we use this term in |
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| 11:50 | context of bacteria, microbes, cyanobacteria others. It's it's not an organ |
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| 11:57 | it's not an organ L we're not about chloroplasts here. Okay. But |
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| 12:01 | do refer to the folded membranes of bacterial type that can do this as |
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| 12:07 | bible codes because they contain these photo . Okay. Um and of course |
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| 12:14 | a sightedness because again many of these being used to pump protons out. |
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| 12:18 | , so it will be a charge in a in a concentration. Um |
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| 12:27 | so the first system we'll look at is not quite almost like so here's |
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| 12:32 | an absorption spectrum. Okay, absorption a range of wavelengths. Okay. |
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| 12:40 | so the chlorophyll uh blues and reds kind of are the peaks particularly blue |
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| 12:47 | . Um so by absorbing the blue red light, you Perfect green. |
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| 12:52 | , fair degree. And so um chlorophylls. Okay, so chlorophylls, |
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| 12:59 | we see in allergy plants santa bacteria chlorophylls are what we see in these |
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| 13:06 | bacterial photo probes um that have a system but not the complete system that |
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| 13:15 | algae in santa bacteria have. so so there's gonna be some difference |
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| 13:20 | that absorption. And so what we here is bacterial chlorophyll particularly absorbs light |
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| 13:25 | the low end. Okay. Low meaning uh low energy. Okay, |
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| 13:31 | remember as wavelength increases energy decreases, ? So wavelength that is short and |
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| 13:39 | the left is more high energy So um so really in uh when |
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| 13:47 | look at say an aquatic system. um your your oxygen IQ for the |
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| 13:56 | . A global light in the more energy range blues typically, and they |
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| 14:01 | be higher in the water column. , further depth there'll be more there'll |
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| 14:05 | more on top. Okay, because light hits water of course gets refracted |
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| 14:10 | loses energy. So those those types oxygen synthesizing appeared will be on the |
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| 14:18 | layers of the water column below So energies. And so they absorb |
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| 14:24 | energy. Higher energy type. And lower one energy light trickles down right |
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| 14:30 | electrically below your your oxygen and photo . And in fact many of them |
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| 14:36 | also in the sediment, the lowest depths. Okay, how are they |
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| 14:41 | this lower energy light. And so so we'll look first at uh the |
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| 14:49 | IQ system. Okay, so plants but um cyanobacteria and algae. |
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| 14:56 | , so they have the complete um system sort of system one and |
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| 15:02 | Okay, so Here is uh so in the order of 2-1. Because |
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| 15:09 | the order of worship of discovery that resistant to contain the is linked to |
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| 15:15 | ATP formation. Okay, so the phosphor relation. So light hits Photo |
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| 15:23 | two complexes That energy absorption leads to a release of electrons. So basically |
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| 15:31 | system to becomes oxidized gives up Right? So if you then have |
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| 15:39 | then keep again, it's all about we learned previously. Keeping electrons flow |
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| 15:44 | right. So we have to have source, right source of electrons feeding |
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| 15:48 | . Okay, so that's where the tosses reaction comes in. Okay, |
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| 15:53 | water serves as a source of electrons this system. So when this solar |
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| 16:00 | too folks like loses electrons, it a very powerful oxidizing agent. |
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| 16:07 | very powerful Oxidizing oxidizing agent wants to reduced. Right? So as it |
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| 16:14 | electrons and then we'll grab so to electrons from water. Okay. And |
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| 16:20 | the water's oxidized two oxygen. And hence this is the oxygen |
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| 16:27 | This is why we call it that is evolved. And the electrons have |
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| 16:31 | passed on the rotor system to so this is kind of so as |
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| 16:35 | hits it again, those electrons takes from water like this is kind of |
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| 16:39 | feeds the source here, source feeding process, but it's driven by |
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| 16:46 | Okay. Hence for Okay. Uh then very similarly to what we talked |
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| 16:53 | before in the context of for Okay, electrons are passed down to |
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| 17:01 | carriers and again, it's the same of of more positive reduction potential. |
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| 17:07 | ? That's what keeps the flow going that's coupled to the proton pumping. |
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| 17:13 | . Although not shown here. There's to be an HTTPS which will be |
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| 17:18 | somewhere like this. Okay. And where HTTP formation will occur as they |
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| 17:25 | through the gps. So the this is the same mechanism we talked |
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| 17:32 | before. Keamy osmosis mechanism, proton , etcetera. Okay. It's just |
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| 17:37 | light is the driving force here. . Yeah, that's one way to |
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| 17:45 | about. Yeah. Mhm. Completely . Yeah, there's no similarity |
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| 17:54 | There's really no similarity in terms of the components are not the same at |
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| 18:01 | . But the the process of how works is the same. Um so |
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| 18:11 | electrons of course, without losing energy they are being passed from one to |
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| 18:16 | other. Uh and so the next er basically is third system one. |
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| 18:21 | . And so light energy hits Then again, electrons are bumped up |
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| 18:27 | off to another series of electronic carriers time any of mm hmm to N |
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| 18:34 | D P. And so generally you've in a D N A D |
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| 18:39 | So the N A D P and D P H uh couple any D |
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| 18:45 | are generally seen in bio synthetic Okay, because in a D P |
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| 18:51 | and 80 P are both of you to fix co two making these more |
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| 18:57 | organic molecules, sugars and things. , um so again, just to |
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| 19:05 | here, so electron flow is this Okay? Water to make any |
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| 19:12 | Okay. And then of course here are making https as well. So |
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| 19:20 | have our two energy molecules N. . D. P. H. |
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| 19:28 | formed. Alright, these two So again, because ceo to fixation |
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| 19:35 | a lot of energy. Right? have to continue to be forming this |
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| 19:39 | deform your organic materials. But the , plants or allergy or santa bacteria |
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| 19:45 | for their processes. Okay, um we can see the same thing basically |
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| 19:52 | in this next slide. Uh and you don't need to memorize these these |
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| 19:58 | of these components like cytochrome B. . Or or plaster, sand and |
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| 20:03 | worry about that. Okay, I'm kind of showing you how it would |
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| 20:07 | in the membrane of the organism. , we have our forces to |
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| 20:12 | A couple of two proton pumping as absorbed. The full tosses reaction |
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| 20:20 | There is the presence of oxygen forming another proton pump here and then the |
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| 20:28 | of a teepee. Okay, by that time, by osmosis |
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| 20:32 | And then here is for the system I'm sorry, one, excuse me |
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| 20:37 | , one light absorption electrons pandit off to N. A. D. |
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| 20:43 | . For DPH. So energy Okay, so for each oxygen formed |
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| 20:52 | results from the oxidation of two two moles of water, the production |
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| 20:57 | 2 83 80 PS. Okay. So that's the oxygen in the |
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| 21:05 | Okay, so two photo systems. , because what we're going to see |
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| 21:11 | the next two systems is among bacterial that photosynthesize on. Unlike this |
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| 21:18 | they either have Photo System one or , not both together. And that's |
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| 21:23 | the difference between between the three This has two photo systems. The |
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| 21:28 | ones either have one or the Okay. Um Other things here, |
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| 21:37 | water is oxidized. Okay, oxygen . Right? So oxygen is not |
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| 21:42 | or reduced. Its just by product the oxidation of water. Um SOO |
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| 21:50 | does get reduced reduced to form these complex organic molecules. Um Many |
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| 22:00 | Okay, I think you've probably seen number of times already. So let's |
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| 22:05 | at um These other two. So last two photo systems are variations. |
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| 22:12 | this group agreed sulfur types have just system one. Okay, so that's |
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| 22:17 | system that's linked to N. D. P. H. |
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| 22:21 | Okay? Um And so it absorbs . That's kind of low energy, |
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| 22:27 | ? Compared to the previous system 6 . Alright. 700. And this |
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| 22:33 | is 8 40. So considerably less But it does have a full tosses |
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| 22:41 | . And so typically it's uh two s. Hence we typically college |
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| 22:47 | sulfur for that reason it oxidizes H S. But it can also there's |
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| 22:52 | that can use hydrogen gas or iron iron as a source even even succeeded |
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| 22:59 | some cases. So um but has only a PS one system attract |
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| 23:06 | in a DPH production and some for strange reason A. D. |
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| 23:10 | Okay. So there is some variation . Um So the process we see |
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| 23:17 | , so this is an example. some of your green sulfur types collect |
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| 23:22 | chlor fields, bacterial flora fields in complexes called chlor zones. Okay, |
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| 23:28 | these aren't organelles. Uh It's not not a lipid violators. Or when |
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| 23:32 | see some lipid molecules are not arranged a typical bilateral like memory, but |
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| 23:39 | does uh collect these chloroform molecules in dense packet here, so to speak |
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| 23:47 | photons of light energy absorbed. And passed that onto these um the photo |
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| 23:53 | . Okay. And so the oxidation hydrogen sulfide in this case. |
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| 24:00 | It gets oxidized electrons passed down eventually N. A. D. |
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| 24:04 | Or any de deformity DPH fingers on Fix you to these are photo water |
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| 24:11 | . They do Fix Co two. the question is how can they make |
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| 24:15 | teepee? Well of course they can a teepee but it's just through a |
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| 24:22 | pump so they can generate protons From oxidation of H. two s. |
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| 24:27 | example here. Okay and those can and form a gradient. Okay. |
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| 24:34 | they'll have an A. T. . A. For which they can |
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| 24:37 | and produce a piece. It's just a system that's part of the PS |
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| 24:42 | system. Right? It's independent of . So they have PS one to |
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| 24:45 | an A. D. H. they can't agree. Ready Informa Https |
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| 24:51 | the same mechanism is just not associated the PS two system. Okay. |
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| 24:55 | but again they are they are photo troughs. They do Fix Co |
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| 25:00 | Okay. Um in the last system is one that has just PS two |
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| 25:08 | PS one. Okay. And so these are really low energy. So |
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| 25:14 | see the 870s and we like the and floor. That's really infrared |
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| 25:19 | Right? And so that's a really low energy. Such that it's not |
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| 25:27 | really to have a full toxic reactions with it. Okay. So what's |
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| 25:33 | it then? In terms of Well, it's a secret system. |
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| 25:39 | So electrons that it possesses here when is absorbed, those electrons are passed |
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| 25:44 | to the to the components of the but then are recycled back. |
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| 25:49 | And again it's really because of the energy of light they absorb. |
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| 25:54 | But because it's like the PS Okay, it will uh form the |
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| 26:02 | proton gradient will be able to form tps. Alright so it's a way |
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| 26:05 | it to suddenly form get energy but but this group unlike the previous |
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| 26:12 | these guys are photo hetero tropes. so they are photo heterosexuals. Uh |
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| 26:20 | hiding here. Okay, so uh they it's a way for them to |
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| 26:26 | supplement their metabolism and get energy using . But they do cantab allies. |
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| 26:30 | they have to have a more complex carbon sources. Okay, um this |
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| 26:37 | in general, these purple non sulfur are very versatile. They can be |
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| 26:45 | this guy using life plus metabolize. There's something that can act like a |
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| 26:51 | little trophy as well. So that of can span almost three types of |
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| 26:54 | in one certain species can so it them very versatile. He's typically typically |
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| 27:01 | in aquatic sediments um easily. But but again, the cyclic little electrons |
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| 27:12 | . Okay. Uh so if we kind of summarize all three of these |
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| 27:17 | one shot and look at it this . Okay, so here's the first |
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| 27:23 | of debt oxygen in photosynthesis. Okay , allergy plants, standard bacteria. |
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| 27:31 | , so two photo systems. my absorption into the first, the |
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| 27:36 | system too, that's linked to a formation. Photo phosphor relation Photo System |
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| 27:43 | absorbs light electrons then transfer to form DPH. And so again these are |
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| 27:49 | of trucks. Okay, uh then have bacterial degree in sulfur types only |
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| 27:57 | the system. One alright, link any DPH formation and oxygen IQ. |
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| 28:02 | , so there's no oxygen formed as byproduct here. They're using H two |
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| 28:06 | . There's no auction being formed. . Hence and pathogenic. Uh these |
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| 28:11 | are photo autotrophs. They do produce T. P. S. Of |
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| 28:15 | but just not. It's just not to a photo system to process. |
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| 28:20 | last group we just looked at has photo system two. Okay. They |
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| 28:26 | not um they're not they're not going fix fixing. Which is why it |
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| 28:33 | the screen. Okay so again linked photos too proton pump ADP for |
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| 28:40 | And again an oxygen. There's no being formed here. Okay so you're |
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| 28:45 | three types. Okay um many questions . Okay so let's summarize all this |
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| 28:55 | the question here at the end. so uh let's take a look at |
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| 29:01 | . Which is the following statements. is true concerning photo trophy among hello |
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| 29:08 | and cyanobacteria, green sulfur bacteria and non sulfur bacteria. So look at |
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| 29:15 | options there and see what makes Mm hmm mm hmm. Mhm mm |
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| 30:30 | . 10 seconds. Okay. Just reminder. All the all the three |
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| 30:39 | you need is up everything you need exam three and they're not thinking about |
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| 30:43 | now but that that's all available to . Mhm mm hmm. Okay so |
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| 30:59 | the halo archaea. So bacterial chlorophyll photo tropes to absorb green light. |
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| 31:04 | that true or false false? Because not chlorophyll based. Right? It's |
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| 31:13 | or adoption based. Okay. Center are that's wrong because they are their |
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| 31:21 | it right. C is not right chlorophyll based. Right. Not bacteria |
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| 31:30 | often sort of image. There's a and non chlorophyll based have actually I |
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| 31:35 | together before class A a table and course uh it'll be available on |
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| 31:42 | Uh So you might you might find helpful. So the correct answer here |
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| 31:46 | D right green sulfur bacteria. Photo possessing photo system one linked to any |
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| 31:52 | in some cases and A. H. Depending on the strain |
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| 31:56 | So here is the table. Um . Okay sorry for the small |
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| 32:05 | Uh But again just to through kind I made about a couple things out |
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| 32:10 | to put the many things the trophy . Non forkful baseball for bass. |
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| 32:16 | photo pigments you find in each Okay. Light absorption through retinal |
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| 32:23 | Two photo systems here here but they're these two groups right there together in |
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| 32:29 | groups. Features like the pump. are photo header. Tropes absorbing |
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| 32:36 | These are the kind of representative Ah And so again uh you might |
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| 32:42 | helpful. It'll just look on the blackboard under the electric notes for unit |
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| 32:48 | and it'll be sitting there. Okay think those most of the main features |
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| 32:54 | know. Um A questions. Yeah all folks. So go to lab |
|
| 33:05 | wait for lab or if you don't to go to lab you can go |
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| 33:09 | . It will be yes. Um I guess uh individuals were just remember |
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| 33:25 | the complex we have to remember, visually what it looks like the which |
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| 33:32 | like, you know, just if just have a general idea, a |
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| 33:38 | of, Okay, here's just the of electrons, how the electrons flow |
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| 33:43 | the system. So PS two of PS two PS one like that. |
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| 33:48 | don't even know memorized structures and things that. Or even like the it |
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| 33:55 | like different electron carriers, like pasto for yourself. You don't need don't |
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| 34:00 | to memorize that. It's kind of basics. Yeah. Yeah. |
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| 34:13 | Start using three on Wednesday, Okay. Mm hmm. |
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