Electron Transport Chain - Video Tutorials & Practice Problems
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1
concept
Intro to Electron Transport Chain Concept 1
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In this video, we're gonna take a look at the electron transport chain. Now, here, the electron transport chain which is abbreviated as etc is one of the last steps of aerobic respiration of metabolism. Now, here we're gonna say that it is a series of redox reactions that harness the energy of electrons from N A DH and FA DH two co enzymes. Here, they're acting as electron carriers. Now fa DNA DH and FA DH two are produced within the citric acid cycle. Now, here, if we take a look, we have our electron transport chain, we have our cytoplasm, then we have our outer membrane with our outer membrane, we have our inner membrane. So in between them is our inter membrane space. Now, after that, we have our mitochondrial matrix. Now you'll notice that within this image, we have these free floating H plus ions within the inter membrane space embedded within our inner membrane. We have these globs here. These represent complexes. So we have complexes uh +123 and four, we also have a coenzyme and coenzyme Q and then we have cytc, this is basic, basically cytochrome C, this acts as a multifunctional protein and it acts as another electron carrier within the electron transport chain. And what we have here basically is the moving of, of N A DH towards complex one where it drops off electrons for complex one. And here we have N ad plus being created because N A DH is given away its electrons. This is al also acting as a pump that pumps that H plus ions to the other side into the inter membrane space. We also have FA DH two which dumps electrons to complex two and becomes F ad here it is next to the co enzyme Q it doesn't pump protons to the inter membrane space. We have our complex three which is also pumping H plus ions into the inter membrane space. We have cytochrome C which is helping to facilitate electrons transferring from complex three to complex four. Complex four is also pumping H plus ions to the inter membrane space. And as these electrodes are getting transferred, they're being given to 02 which eventually will get reduced into water. So this is basically just a quick glance of the steps of the etc here. So we're creating this kind of gradient where there's a build up of positive charges in the inter membrane space. And then we have these electrons that are traveling along from complex 1 to 4, working with this idea of redox reactions. These different types of charge build ups on different sides, right. So just remember we're gonna talk about how this will lead eventually to the production of A TP.
2
example
Intro to Electron Transport Chain Example 1
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1m
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Which of the following correctly describes the electron transport chain here harnessing of energy from high energy electrons from crept cycle. That's true because remember the production of N A DH and FA DH two represent high energy molecules. They get shuttled over to the electron transport chain and we harness their energy from their electrons in order to eventually generate a TP. So this is true. The breakdown of N A DH and FA DH two to carbon dioxide. No, they just pass along their electrons to and become oxidized and return back to their N AD plus and F AD uh structures. So they're not being changed into carbon dioxide. Oxidation of N A DH and FA DH two co enzymes. Yes, this is true. So they're giving up their electrons. N A DH gives its electrons to complex one to become N ad positive again, fa DH two hands over its electrons to complex two to become F ad again, since they're losing electrons, they are being oxidized redox reactions facilitated by enzyme um complexes and electron carriers located in the inner membrane of the cell. So remember this is happening in different places. It's happening within the um inner membrane, yes, with the embedded enzyme complexes. But N A DH and fa DH two, they are part of the mitochondrial matrix. So that's not taking into account that location as well. So this is not uh completely true. So here the answer would be options A and option C.
3
concept
Electron Transport Chain Process Concept 2
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2m
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Now, the electron transport chain uses energy from electrons to generate H plus ion gradient by pumping H plus ions into the inter membrane space. Now, here, as we're pumping these H plus ions into inter membrane space or we're increasing the concentration of H plus ions which would cause a decrease in our Ph. Now here, if we take a look and break this up into seven steps. So in step one, we're saying that N A DH transfers electrons to complex one. So N A DH here is handing over electrons a complex one becoming oxidized and regenerating N ad positive in step two fa DH two transfers electrons to complex two and it becomes F ad it's being oxidized as well. Complex one and complex two will transfer electrons to coenzyme Q. So they're being transferred here to Kansan Q. Coenzyme Q then takes those electrons and transfers them to complex three. Now, complex three transfers them to cytc which is just cytochrome C. This is just a multi uh functional protein that acts as an electron carrier as well within this whole process. Then we're gonna say cytochrome C transfers electrons to complex or, and then we're gonna say here that finally that our electrons will be accepted by oxygen or 02. And we're gonna say here, oxygen f acts as the final electronic cept and we're gonna have it eventually being reduced into water. Now, notice we have H plus being pumped by complex one, being pumped by complex three, being pumped by complex four. It doesn't happen with complex two. Here, it's complex doesn't move o move into the inner membrane space like the other complexes. So note only complexes +13 and four pump H plus into the inter membrane space. So basically, this is the chain of the movement of uh H plus ions as well as electrons from complex one all the way to complex four to eventually having +02 being the final electronic sector.
4
concept
Electron Transport Chain Process Concept 3
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1m
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Now, when it comes to the final electronic acceptor, the final molecule that accepts the et CS electrons is oxygen gas. We're gonna say here that oxygen gas interacts with the hydro ions or H plus ions in order to form water when it comes to the etc. The summary of the important reactions are from complex one, we have N A DH plus a hydro ion plus coenzyme Q. This would give us N ad positive. It's N A DH has been oxidized and coenzyme Q gains two hydrogens in the process and it becomes coenzyme qh two for complex two. Remember this is where F fa DH two drops off its electrons. We're gonna say it interacts with coenzyme Q. We're gonna say here when it gives away its two hydrogens or, and electrons here we're gonna have F AD and then coins and king picks up two hydrogens. And then finally, for that matrix itself, we have four hydro ions plus four electrons interacting with oxygen gas. As a result. At the end, we get two moles of water. So these represent the summary of our etc reactions
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Problem
Problem
FADH2 can be oxidized at both complex I and II in the inner membrane of mitochondria. (T/F)
A
True
B
False
6
Problem
Problem
Write a reaction representing oxidation of NADH coenzyme.
A
NADH2 + CoQ → NAD+ + CoQH2
B
NADH+ H+ + Cyt c → NAD+ + Cyt cH2
C
NADH + H+ + CoQ → NAD+ + CoQH2
D
NAD+ + H → NADH + CoQ
7
Problem
Problem
Protons are pumped into the intermembrane space due to:
A
Energy provided by the electrons as they pass through complexes I, III & IV.
B
Decreasing of the pH in the intermembrane space.
C
CoQ pumping electrons through the complexes.
D
Formation of water from final electron acceptor.
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Problem
Problem
The mobile electron carriers of the ETC are:
A
Complex I & II
B
Complex III & IV
C
NADH & FADH2
D
CoQ & Cyt c
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