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0:01
hi everyone welcome to unit 2 chapter 4 where we will be learning about cellular respiration this means how cells get their energy as always if you click on this book you get a link to the guided notes please use those to uh improve your note taking and you may get a chance to turn these in for extra credit at the end of the semester so we are learning about cellular respiration or how organisms get their energy that divides organisms into two main categories
0:31
autot tropism self-feeding or heterotroph ISM we are heterotrophs meaning that we have to consume food to produce energy autot tropes however they don't they can absorb other chemicals or sunlight to produce energy the most common type of autot tropism is photo autot tropism organisms that use sunlight to undergo photosynthesis this includes Plants algae and cyanobacteria or uh bacteria that can undergo photosynthesis there are other types of organisms such as deep sea bacteria
1:08
which have chemo autot tropism they use chemicals but we're going to talk about photo autot tropism heterotrophs including ourselves are going to gain energy by eating autot tropes heterotrophs can also eat other organisms that have already eaten the autot tropes so if we were to organize um this chart into autotrof versus heterotroph phytoplankton would be an autotrof it is a type of photosynthetic um ocean Plankton or algae the little boy would be a heterotroph because he has
1:44
to eat his veggies to grow big and strong then we have the kitty cat uh kitty cats normally don't eat plants but they do eat mice and other small mammals which eat the plants and then we have a par tree the parat tree would definitely go into the autotop because it underes photosyn synthesis now let's talk about photosynthesis photosynthesis uh we're going to talk about in um plants okay so other organisms do undergo photosynthesis but we're going to talk about plants all
2:15
photosynthesis is going to happen inside the mesop cells so inside the green part of the plant there are other structures within the plant that do not undergo photosynthesis most photosynthesis is going to happen inside of the leaves of the plant okay this is where most of the mesop is located on the underneath of the plant are little uh pores called stoat which allow oxygen to enter and exit or CO2 can enter and oxygen can exit through the stoa okay this is at the bottom of
2:50
the plant let's turn on my pen so if I were to have a plant leaf the bottom of the leaf would have these little openings they look like uh lips almost they're little openings and the plant can actually open these to allow CO2 inside and oxygen out but they can also close them if it becomes dark and they no longer want to undergo transpiration we're also losing a lot of water out of these pores to evaporation now inside of the mesop this green pigment actually comes from
3:25
something called chloroplast this is a special organel in side of the plant that holds a lot of chlorophyll chlorophyll is the green pigment and that green pigment actually is inside of something called a thid okay the chlorop pass can be divided into two main parts the stroma which is like the cytool and the thid let's see a picture of that so here's a picture of the chloroplast you can see that it has a double membrane much like mitochondria it also has DNA and independent
4:02
ribosomes just like mitochondria and this supports our theory of um endosymbiosis so the theory is that these chloroplasts used to be a bacterium that now is in a symbiotic relationship with all plants now besides the double membrane on the outside the plant actually has a third membrane on the outside of these thilo coid discs these thid discs inside the Lumen or the membrane on these discs is where you're going to find all of the photosynthesis that's happening this
4:40
is due to those pigments so the thilo coid is very very similar to the chiste of the mitochondria photosynthesis can be broken down into two main parts the light reaction which is of course light light dependent and the Calvin cycle which is light independent okay it's named after some guy named Calvin now these two reactions work together to produce sugar so what goes into photosynthesis well first we have to have light light goes into it water goes into
5:20
it and uh some other other products like CO2 goes into it okay in the light reaction we taking water and splitting water apart and taking the energy from the Sun and all of this is happening in the thids okay especially in the membrane of the thids so in these Stacks where chlorophyll is we have a byproduct of oxygen we actually don't need the oxygen we just release it into the air
5:51
or the plants do because it's not part of the next step but the main purpose of the light reaction is to produce these two items the the light reaction is going to produce energy in the form of ATP and it will produce something called nadph by itself nadph is not that interesting but the interesting part is that nadph carries electrons and we need those electrons so this is our electron carrier
6:19
in adph so this is two different forms of energy that will feed the Calvin cycle the second half of this process now the light reaction happens during the day when we have light this dark reaction or light independent reaction can happen 247 it's not constrained to whether it's light or dark outside it is constrained to how much ATP and an adph is available so as long as there's ATP and nadph available this plant can undergo the light independent reaction the Calvin cycle
6:53
the whole purpose of the Calvin cycle is to take carbon dioxide from the atmosphere and form it into a six carbon sugar so we're going to take six carbon dioxides we're going to need six of these in order we've got CO2 in order to make sugar which has six carbons 12 hydrogens and six oxygens okay so we need six carbon dioxides so this process has to happen six times in order to get one glucose molecule now let's talk about photosynthesis a little bit here I have a picture
7:35
of a solar panel so sunlight will come and excite the solar panels and the solar panels will produce charged ions so these charged ions will go down this cable and be entered into the battery for chemical storage or potential energy so we're storing the energy in the form of a battery here this is the same process that's happening here where we have the light reaction which acts as the solar panel which produces this cellular energy this nadph and ATP so our solar panels
8:12
are producing electricity and sending it through these wires to the battery the battery is kind of like the Calvin cycle because we are producing stored energy in the form of sugar so this is going to be our battery this sugar can then later be used for cellular respiration by the mitochondria the light reaction we're going to talk about the light reaction first the light reaction is of course dependent upon light the sun projects all kinds of different lights but
8:49
humans are only sensitive to this very small range of visible light or the visible light spectrum and plants are sensitive to an even smaller range now you'll notice that the plants do really well in this uh 400 to 525 range they do really well here this is the Violet and blue color then in green and yellow we really don't have much action at all and then we have a little bit of action here
9:17
in the red uh Spectrum so plants actually reflect green light which is why they look green to our eyes because the plants are reflecting that green color to our eyes so plants actually do not thrive in green light they thrive in purple and blue light this is due to the pig the plant pigments um mainly chlorophyll there's two different kinds of chlorophyll chlorophyll a and Chlorophyll B and there are also keratinoid like xanthophyll and katene so these pigments get
9:55
excited at different wavelengths of Light which is why many plants will have more than one kind of chlorophyll so that they can absorb more than one kind of light so if I were targeting plants and I could only use one spectrum of light I would choose this right here maybe 430 because this would Target the plants the best because we have the most action from all three different types of uh color pigments I would never choose a pigment or a light spectrum in the 600 range 550 to 650
10:30
because the plant would simply reflect all of that light and the plant would not be able to grow now interestingly over here in the red light you can create a greenhouse using red light but you will only be able to grow plants that use chlorophyll a okay you wouldn't be able to grow plants that use uh keratinoid because they simply wouldn't react or respond to this wavelength of light and
10:55
the wavelengths of light are associated with how much energy the photons have so for instance these cosmic rays have very short wavelengths or very high energy whereas these like radio waves have very long waves like infrared has a very long waves so as far as energy goes the plants are responding to these high energy waves over here in the purple and violet area so this is says imagine
11:27
you are a farmer on Mars and you have a greenhouse with artificial light the lights are broken so you can only select one wavelength what wavelength would you avoid well as mentioned before I would avoid these wavelengths so I would not use any light in the 550 to 650 range because they will just reflect the light they will not absorb it the plants however over here are absorbing light from
11:53
400 to 500 but if I chose a spectrum within 500 I wouldn't get a good reaction from chlorophyll and I would just get a good reaction from the carotenoids so in the next question where it says which wavelength of light would you use to Target growth probably this one right here at 4:30ish right here because all three of the plants grow really well at that length if I chose 500 I would get a good reaction from keratinoid but not from the chlorophyll and if I chose 400 I would get a
12:25
good reaction from chlorophyll a but not such a good reaction from Chlor F be um I could choose something in the 700s but if I chose 700 I would be eliminating the carotenoids all together and I would only be getting a reaction from chlorophyll so the best uh wavelength of light would be around 430 of course sunlight includes all of these wavelengths so plants grown outside don't really have to worry about this but when we get into artificial light some light that may appear
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as white to you and I don't actually include the entire spectrum of visible light so what happens once the plant actually receives the light in the light reaction well plants include chlorophyll and the chlorophyll is arranged in photos systems keep in mind that all of this is happening inside this membrane of the thid so what everything that I'm talking about right now happens just inside the
13:26
membrane of the thid so these photo systems or these photo pigments are inside the membrane of the thid when sunlight comes in and excites one of these pigments let's say it excites this pigment the excitement will cause it to vibrate and it will bump into the next one exciting the next one which will bump into the next one exciting the next one eventually they all get so excited that they are all vibrating and kind of focusing and pushing pushing this Center photo cell and
14:02
all that energy is sent to this photo cell which then loses an electron so our goal is to get that electron that's the purpose of the photo system the photo system is collecting electrons from the sunlight so our original energy was sunlight um this reaction Center complex is usually a different pigment than the others but they all become excited and then kind of focus all that excitement onto this photo center which will then release the electron and the electron will be
14:34
sent to the electron acceptor which will'll talk about in a moment so here are uh photo systems right here we actually have two different photo systems that are in that Philo coid membrane they are ordered photosystem 2 and photos system one it's not backwards we discovered photosystem one we as in scientists discovered photosystem one first and then photos system 2 was discovered and we actually discovered that photos system 2 happens first in this cyclic electron flow
15:08
so once sunlight hits the photo system it will excite and release an electron to the photo uh the electron acceptor which will then start a kind of cascade sequence the electrons are eventually recycled and sent here okay so we ended up with an electron up here and then it went down this electron chain which then lands in the next photosystem which sunlight will again excite and send up to the next uh Cascade now where do we get the electrons in the first place well at
15:44
the beginning we said that we need water H2O water is actually split into oxygen which is then a byproduct or it is lost we don't need it but we did produce two hydrogens okay and they have a positive charge we also produced that was an e electrons so this electron came from the water so this electron in photosystem 2 came from splitting apart water okay that electron got excited was sent up to the electron transport chain here now during this chemiosmosis or during
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this electron transport chain more hydrogen is pulled from outside of the thilo into the thid space so not only do we have these hydrogens from the water but we have extra hydrogens being pulled in just due to these electrons this is called linear flow linear electron flow because it just flows in a straight line to photos system two photo I'm sorry to photos system one photo system one has a cyclical um system because it can excite itself but the product of photos system one
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is going to be nadph which if we remember nadph was our electron carrier right here so our goal is to produce ATP and nadph so we have not yet produced ATP but we did produce nadph and nadph is going to be our electron carrier so this extra electron is transferred onto nadph and used in the Calvin cycle where are all these hydrogens going well they're going inside the thilo coid so this
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is the membrane of the thilo the thid is up here inside the thilo coid are tons of hydrogens okay and remember the hydrogens got there because of the light reaction because not only did we split apart water inside the thilo coid to get hydrogens we also got extra hydrogens from the electron transport chain so we have all these hydrogens this has set us up perfectly for an electrochemical gradient since we have so many hydrogens inside the piloid they are constantly
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wanting to get out the only way they can get out though is through this enzyme called ATP synthes so ATP synthes conveniently allows all of the hydrogens to exit but on their way out they have to do a job and that is to create ATP ATP synthe synthesizes ATP so this is going to be our next product for the light reaction the first product was nadph right here and the second product is ATP both of those products are going to feed into the Calvin cycle so here it is all together we
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have light that is going to excite this photo system too we did need water water and water is going to be broken down into oxygen which is then released and hydrogen so we already have a bunch of hydrogen in this space a bunch of positive ions in this thid space now these electrons get excited because of the photo pigment in the photo system too and the electron is going to move down the
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electron chain to the electron acceptor which then will pass the electrons to um another electron acceptor the cyto chome Pro uh complex and during this process we're pulling more hydrogen into the system so now we have even more hydrogen or positive ions in the thid space these electrons continue to travel until they reach photo system one they need to be re-energized with sunlight so
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sunlight hits the pigments inside of photo system one and excites those electrons the electrons go down another electron chain but they now are going to be added onto nadp okay so nadp is turned into NAD pH which is our electron carrier this is where we're going to get the electrons from the electron carrier goes to the Calvin cycle and all of this uh positive ions they're built up inside the Philo coid they want to escape the only way they can escape is through ATP synthes
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ATP synthes used the energy from all of those ions will add a phosphate onto ADP producing a TP energy which will then also feed to the Calvin cycle so the next question is going to say which products from the light reaction are needed for the Calvin cycle if you would like to watch the video you can go back to the lecture uh PowerPoint and watch those videos but the sound does not play
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so I'm not going to play them during this lesson but they are available if you would like to review them so I am just looking for the products of the light reaction not the allog together products so the products are going to be ATP and nadph that feed into the Calvin cycle we also have a byproduct of oxygen but that is not needed so that is just released into the atmosphere which molecules act as the major electron donor we're trying to get the photo system started
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particularly photo system 2 to get photosystem 2 started we need electrons from somewhere and we are going to get those electrons from water we're going to split H2O into oxygen which is released into the atmosphere hydrogen positive hydrogen which is pressed into the thid space
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and the electrons I'm sorry I'm too close to this uh and the electrons we get two electrons out of it all right and those electrons are what's going to be sent into the electron transport chain all right what is the purpose of the hydrogen ions in the thid space well the hydrogen ions are going to power ATP synthes so to produce ATP is their purpose let's talk about the next step the Calvin cycle the Calvin cycle is going to use that ATP and that nadph
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to produce a six carbon sugar called glucose now that means that this Calvin cycle has to happen six times so it may be a little blurry but this says six we're going to go through this cycle six different times to produce one one glucose molecule because glucose is C6 h126 so we're going to go through this cycle six different times we start out with carbon fixation which is exactly what it sounds like we're going to take carbon dioxide from the atmosphere and
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add it to an existing molecule now this is a six car a five carbon molecule called rubos B phosphate but most places we're just going to see it it's rubp rubos bif phosphate now we have five carbons here one two three four five we only need one more carbon to get to six carbons so we're going to take that carbon from CO2 and pop it on right there right there at the top but this is not exactly stable so it very quickly breaks down into something called 3pg this says 12
23:54
3 pgs that's after we've gone through the cycle six times so one rubp turns into two 3 pgs this is not a a carbohydrate though it is just a three carbon complex we want to turn it into a carbohydrate we need a little bit of energy to do so so in the Second Step reduction we're actually going to use the ATP and the nadph that we uh had from the light cycle and we're going to turn 3pg into something called g3p okay we turn 3pg into g3p the only difference is that this is
24:37
now considered a carbohydrate okay we have this um and we had to use nadph to get there only one of these will go into the products so every time we go through the cycle one g3p is added to the products and that will be used to create sugar okay only one though everything else we have all this left over g3p we consider this a carbon skeleton it is not like a true carbohydrate it's a carbon skeleton and we need to start this cycle over again to get one more g3p over here every
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time we go through so regeneration is the last step where we take this carbon skeleton and it takes a little bit more energy and we're going to turn it back into a rubos bif phosphate or rubp now we stole one carbon from over here so we actually end up with five carbons that are going to be turned into rubos by phosphate because we stole one carbon that's why we have to go through this cycle six different times so we have three steps carbon fixation uses CO2 adds it to rubos
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B phosphate but then it quickly breaks down into a three carbon compound reduction takes that three carbon compound adds nadph and ATP to the system to produce an active g3p or um the precursor to a carbohydrate one of those carbons is going to be added to our products which will eventually become sugar or glucose after six turns but then we recycle the carbon skeletons into rub by phosphate if you would like to watch this video you can view it in the PowerPoint I do suggest it
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it's a great video and it explains why we need to go through this cycle six different times here it says which part of the Calvin cycle is responsible for taking a five carbon uh from the g3p skeletons and creating a rubos bif phosphate so if we're creating rubos bif phosphate I know that this is going to be the Reg generation step okay the next question says which part of the carbon cycle is responsible for taking a three carbon compound and forming active g3p
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with the help of nadph I know that that's going to be the second step because of the use of nadph so I know that that is reduction last step we are taking CO2 from the atmosphere anytime I'm taking CO2 from the atmosphere I know that it's going to be the first step which is carbon fixation
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all right let's talk about photos I'm sorry we're done talking about photosynthesis let's talk about what happens to that glucose molecule after it's made both plants and animals have mitochondria mitochondria is a unique organel which is used to create tons of ATP both plants and animals do this when we talk about glycol I'm sorry when we talk about cellular respiration we're going to talk about one single glucose molecule so if if one single glucose molecule undergoes
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glycolysis we will end up with two pyruvates both of those pyruvates will enter into the mitochondrial Matrix and be turned into acetyl COA acetyl COA will be used in the citric acid cycle to produce ATP but most of the products of all three of these steps is going to go into the electron transport chain and the electron transport chain is where most of the ATP is going to be produced so let's talk about these individual different steps glycolysis glycolysis
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is the first step glycolysis is also called the breakdown of glucose or glucose uh breakdown when we break down glucose we end up with pyruvate or two different pyruvate we're not focused on fermentation right now just respiration so we end up with two pyruvate which turns into a cetl COA eventually if we're talking about glycolysis glycolysis is happening in the cytoplasm or the cytool the cytool is is anything outside of the mitochondria so it's not happening inside
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the mitochondria it's happening outside the mitochondria and it also does not need oxygen it is Anor robic so it does not need O2 it does not need oxygen we don't need oxygen um this happens outside of the mitochondria once we get inside the mitochondria we're talking about pyate oxidation and the citric acid cycle and the electron transport chain so all three of those steps happen inside the mitochondria pyruvate oxidation um or the citric acid cycle
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is going to happen inside the Matrix of the mitochondria so inside this part the main part and then the electron transport chain is going to happen along the membrane or along long the chis day all right um the electron transport chain is going to be very very similar to what we learned in the thids so this electron transport chain is going to be very similar to the electron transport chain that we saw in the chloroplast all right looking at this diagram we first have glycolysis
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glycolysis is going to produce a little bit of n ADH which is our electron carrier okay but we're also going to produce a little bit of ATP okay this is happening outside of the mitochondria everything over here is happening inside the mitochondria once we're inside the mitochondria we're producing a little bit more in ADH which is our electron carrier okay two electrons actually all right and we're going to produce a byproduct of CO2 but we don't need that okay no
30:59
ATP in this section then we have the citric acid cycle aka the kreb cycle we're going to produce a little bit of ATP but what we're mainly going to produce is electron carriers each one of these electron carriers is going to carry two electrons so this is the big money right here because those electron carriers are going to feed into the electron transport chain which produces just tons and tons and tons of ATP the first step glycolysis we already talked
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about glycolysis if we have one molecule of glucose that will split into two pyruvates so at the end we end up with two pyruvates so one glucose turns into two pyruvates this does not require oxygen um and it happens inside the mitoch I'm sorry it happens inside the cytoplasm so outside of the mitochondria now glycolysis happens in two different stages the first stage is called the investment stage we actually lose 2 ATP so we have -2
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ATP then we have something called the payoff stage um or the harvesting stage but I like to call it the payoff phase the payoff phase we actually gain 2 ATP and 2 ATP plus four ATP okay during this stage we also produce a little bit of nadh which is great so if we lose 2 ATP and we gain 4 ATP we have a net gain of 2 ATP net but the other important thing is the production of nadh because that's our electron carrier we want to pay attention to those so if I were to write this in a
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diagram okay if you have your guided notes you already have this Step One is glycolysis it's happening inside the cytoplasm it does not need oxygen and it produces two nadh and two ATP but remember this is net ATP net ATP that means we actually produced four ATP but we lost two in the process if you would like to watch this video you can watch it in the PowerPoint
33:29
now the next stage is going to be pyu oxidation basically this is an intermediate step before the citric acid cycle okay we cannot use pyruvate in the citric acid cycle so pyruvate has to be turned into something called acetal COA okay we need two acetal we're going to get two acetal COA um from one glucose molecule one acetyl COA from one pyruvate so when pyruvate enters into the mitochondria it loses a carbon dioxide and it gains a co-enzyme but we're also going
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to produce a little bit of nadh which is our electron carrier carries two little electrons so this step is important as an intermediate step I think that's supposed to be like that it's an intermediate step but it does produce a little bit of nadh which is really important later on it doesn't actually produce any ATP so in this section pyruvate oxidation you could say that this happens in the mitochondrial Matrix we produce two nadh but zero ATP and remember
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each of these is carrying two electrons so this is actually Four electrons in each of these stages next is the citric acid cycle I do not require my students to memorize all of the intermediates of the citric acid cycle but it is named the citric acid cycle over its first first intermediate uh enzyme or its first intermediate citric acid so pyruvate is turned into acetyl COA and acetal COA enters into the citric acid cycle right here at the top it turns into citric acid
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but what I want you to pay attention to is what enters the system and what exits the system so what's entering the system is a cetal COA we have two acetyl COA for every glucose molecule that we're processing now each acetyl COA is going to produce one 2 three nadh for a total of six nadh per glucose molecule so we only have three nadh per uh acetyl COA um but six all together because we have two of them then we are going to produce one ATP which means we get a net of 2
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ATP and we also produce something called fadh which is very similar to nadh so we have two fadh okay so one acetyl COA produces three nadh one fadh and one ATP but one glucose molecule is going to produce double that you can watch this video by looking at the PowerPoint it's a great video but we're going to move on to our chart the citric acid cycle we are producing six nadh and two fadh per one
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glucose molecule so all of this is per one glucose molecule we're also producing two ATP but again the great thing about these electron carriers is that each one of them is carrying two electrons so that's going to end up being a whole lot of ATP down here in the electron transport chain oh that was awful electron transport chain all right what is the net product of the citric acid cycle we only produced 2 ATP but that is not the important part the important part is the six
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nadh's and the two fadh next is going to be chemiosmosis or my favorite step the electron transport chain so all of this is very detailed information about this diagram right here so I'm going to skip ahead this diagram is showing the electron transport chain which is my favorite part of uh this whole process because all of those intermediates that we've collected all of these electron carriers
38:06
that we collected are now going to produce tons and tons and tons of energy for us to produce ATP so to me this is the coolest step we have four different proteins here called protein 1 protein 2 protein 3 and protein 4 super original name but we start out with protein one at least it's in order the nadh that we produced earlier will donate two electrons to the system which excites the system and allows it to pump hydrogen into the intermembrane space so if we have a mitochondria
38:46
and we have chiste here this process is happening along this membrane right here and we are pumping hydrogen into this intermembrane space the space in between the inner and the outer membrane tons and tons of positive charge out here in the intermembrane space so we've pumped hydrogen using this first uh enzyme here and then the electrons hop on to this next enzyme we also at this point can add more electrons using fad so more electrons and that is pumping
39:23
even more hydrogens in this third system so t T and tons of hydrogens are being pumped into the intermembrane space and this continues with the fourth uh enzyme as well all all of them are using either nadh or fadh electrons and producing pumping hydrogens well those extra hydrogens are going to activate the electron transport chain um all these hydrogens are pushing and bumping into
39:55
each other and they really don't want to be stuck in this intermembrane space so conveniently there is a way out but the only way out is through ATP synthes so when they pump back through into the mitochondrial Matrix this inner part they are producing ATP ATP synthes will take a phosphate and add it to the end of ADP producing ATP we can produce up to 28 ATP molecules so tons and tons and tons of ATP being produced just by this one enzyme okay just by this one enzyme now all
40:33
of this extra hydrogen needs to go somewhere and we're kind of messing up our um our little I'm so sorry I forgot the word um concentration gradient we're messing up our concentration gradient if we let it stay as hydrogen so what's going to happen is two hydrogens along with these extra electrons that were were released after enzyme 4 after protein 4 the electrons will join the hydrogens and one oxygen to produce water so we actually have a lot of water inside of the mitochondrial
41:10
Matrix all right so the electron transport chain happens in the intermembrane space or along the chist a along that out inner membrane and we're going to get two um two ATP per electron carrier because each one of these has two electrons okay each one of these has two electrons and in here we can see that each electron is going to kind of pump over one hydrogen it's not exact it's not exactly the same but it is about 24 ATP now this can
41:53
vary depending on how many elect we have you know what time this is going to happen maybe how many hydrogens are available how hydrated you are this can change a little bit so we end up if we add up all of this together we end up with about 28 to 36 ATP so we can actually produce quite a lot of ATP in the mitochondria we only got two from glycolysis and we only got two from the citric acid cycle but all of these electron carriers fed straight into to
42:26
the electron transport chain to produce even more ATP this is a wonderful video about the electron transport chain if you're looking for more information about the electron transport chain so the electron transport chain is very similar to the electron transport chain in photosynthesis very similar process what powers the electron transport chain well electrons the electrons that that are found in na pH also we have hydrogens hydrogens are going to help ATP synthes produce
43:07
ATP all right about how many ATP are produced this is not exact but we're going to have about 28 to 36 now we don't just eat glucose okay um I don't know if you've ever had glucose but it's like sickly sweet it's way way way super sweet we don't exactly eat pure glucose we eat a variety of foods but every single one of the foods that we eat can enter into this process at different stages so for instance fats can break down into glycer alahh and enter into glycolysis proteins
43:54
can break down into acetyl coate and enter into the citric acid cycle um so the most common form of energy is sugar because it can go through this whole process but we also get calories from proteins and calories from fats it just will enter into this process at different stages here is a great diagram where you can see how photosynthesis and cellular respiration interact because the byproduct of photosynthesis is going to be glucose which is a storage of energy and
44:26
oxygen well for cellular respiration we need oxygen and we need glucose so those things are going to feed cellular respiration a byproduct of cellular respiration is carbon dioxide which is needed for photosynthesis so all of this is going to feed into each other which is great for plants here is another diagram that kind of shows the same thing that the uh photosynthesis reaction is almost the exact opposite of the cellular respiration um process so here we start
45:03
with carbon dioxide and water and we end up with glucose and oxygen here we start out with glucose and oxygen and we end up with carbon dioxide and water as a byproduct and we get lots of ATP the last thing that we want to talk about is what happens if there is no oxygen so everything that we just talked about is oxygen dependent or aerobic cellular respiration glycolysis does not need oxygen so we're going to get pyruvate anyway so we can start out talking about pyruvate
45:38
if oxygen is present pyruvate can enter into the mitochondria to produce acetyl COA and start this whole process ending with the electron transport chain but if no oxygen is present we're going to end up with either alcohol fermentation or lactic acid fermentation this process is utilized in bread making um wine making uh beer making and also vinegar vinegar is fermentation by yeast in the presence of oxygen so you would see vinegar if oxygen got into your um if you were trying to
46:18
make wine instead of alcohol you would end up with acetic acid or vinegar so vinegar is acetic acid
46:27
now this is a diagram of fermentation fermentation can either be alcohol fermentation or lactic acid fermentation we're still going to undergo glycolysis so we're still going to start out with glucose we still have to spin 2 ATP but we get uh ATP out of it and we get pyruvate so this part stays the same but if there is no oxygen available instead the pyruvate will be broken down by your body a yeast can actually break the pyruvate down into ethanol okay so we produce alcohol
47:04
this is what's used to make wine and beer okay if uh oxygen enters into this process then the yeast will actually make vinegar another byproduct is carbon dioxide which is great for making bread because as the um as the yeast produces uh this alcohol and vinegar it will release a lot of carbon dioxide causing the bread to rise now animals don't undergo alcohol fermentation they undergo lactic acid fermentation and lactic acid fermentation is kind of like if you've exercise
47:42
too hard you used all the oxygen in your muscles and now your muscles have to undergo lactic acid fermentation producing lactate which is what causes your muscles to feel sore okay so they your body broke down the pyruvate into lactate now the goal of fermentation is to recycle this nadh to restart the glycolysis process so we're only producing two ATP at a time each time this cycle goes through so that's why your muscles are really sore because you have to produce a
48:15
lot of lactate to get a little bit of ATP energy um as always we have our chapter homework which you can check your answers with your si leader or email it to me but these can be turned in at the end of the unit after the exam don't forget to print your chapter laboratory write up and bring it to lab or watch the lab video we also have other resources like the textbook and the flashcards
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