Shadowing Practice: Metabolism | Electron Transport Chain: DETAILED | Part 1 - Learn English Speaking with Video
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Alright Ninja Nerds, in this video we're going to go into a lot of detail on the electron transport chain.
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Okay so where does electron transport chain occur?
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Well if you imagine here, let's say we took a big big deep look into the mitochondria.
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This part right here, this line right here, this whole thing right here is the outer membrane of the mitochondria.
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So this is the outer membrane of the mitochondria.
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Then there is the inner membrane of the mitochondria, which is going to have a lot of nice folding.
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You see how it's really, really folded?
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That folding of the actual mitochondria is called the cristae of the mitochondria.
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How do you say that?
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It's called the cristae.
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Again, here it is.
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It's the cristae of the mitochondria.
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It's the inner mitochondrial membrane.
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Again, you get the outer membrane of the mitochondria, and then you have the inner membrane of the mitochondria
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which is going to be folded so they call it the cristae
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then you have this space
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you see this space right here from the inner mitochondrial membrane to the outer mitochondrial membrane they call
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that the inter membrane space then inside of the
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mitochondrial membrane the inner mitochondrial membrane this is going to be what's called the mitochondrial matrix.
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This is where a lot of the Krebs cycle activity is occurring
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and a lot of stuff that you've seen in a lot of these reactions with the
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conversion of specifically the pyruvate to acetyl -CoA and then the Krebs cycle.
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So again, one more time, this is the outer mitochondrial membrane which is close to the cytosol,
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so this is where the cytosol of the cell would be.
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Then you have the intermembrane space, then you have this inner mitochondrial membrane which is folded so it actually is called cristae,
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and then you have the inner fluid of the mitochondria which is called the mitochondrial matrix.
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Specifically the electron transport chain is occurring on the inner mitochondrial membrane.
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And we're going to talk about each component of that in very great detail.
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So let's go ahead and get started.
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How does all of this actually occur?
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Well if you remember we had to start with the glycolysis.
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So we took glucose which was that six carbon unit, oxidized it, generated some NADHs and little bit of ATP,
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2 ATP net, and converted it into two of these suckers right here.
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So two of these puppies.
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What are these three carbon units right here?
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This is called pyruvate.
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This black marker looks good.
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So glucose to two pyruvate molecules, right?
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And this is going to be splitting a six carbon molecule into two three carbon molecules.
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And you're generating these two NADHs, which will take them to the electronic transport chain.
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We'll have another part of this video where we'll take the NADHs and show how they get into the actual mitochondria.
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Because there's a special mechanism for that.
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Okay, then that pyruvate, if there is oxygen present, the pyruvate gets pushed into the actual mitochondrial matrix through specific transporters.
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And then it gets acted on by the pyruvate dehydrogenase enzyme, if you guys remember that complex.
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And then it converts it into acetyl -coate, which is this two -carbon unit.
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So again, right here is your pyruvate.
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You guys should know all of this already.
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And then this is going to be your acetyl -CoA, right?
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Which was generated from that pyruvate dehydrogenase enzyme.
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What was the significance of that?
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You generated two NADHs from that reaction.
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And then if you remember, we're not going to go each step here because we've already done it.
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You know that you'll go through the Krebs cycle.
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And through specific sequences of the Krebs cycle, you generate how many NADHs?
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You generate two, four, six NADHs, and then also you generate two FADH2s.
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So this is the significant part right here.
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How many FADH2s did I generate?
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Two.
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And how many NADHs did I generate total?
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Let's show that in one whole go here out of this.
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Out of all of this, I generated a total of six NADHs from the actual Krebs cycle.
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That doesn't include the two NADHs from the transition step and the two NADHs from glycolysis.
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Now, these NADHs and what else?
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These FADH2s that I generated,
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the two FADH2s here, they're going to be very special because they're going to take those hydrides.
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If you guys remember, they're called hydride ions.
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What's a hydride ion, if you guys remember quickly?
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It's just specifically a proton with two electrons.
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That's all it is.
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That's all hydride is.
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It's just a proton with two electrons.
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These guys are carrying that.
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Now, these two guys are our electron shuttles.
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What they're going to do is they're going to take those electrons and take it to this actual electron transport chain.
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So let's focus in on specifically how NADH is doing it first and then we'll do FADH too.
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Okay, so here we're going to take our NADH.
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So we're going to take one NADH and see how it's reacting right here.
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So what happens is you have this NADH.
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This NADH is going to come into this action, it's going to react with this first part of the electron transport chain.
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And what's going to happen is it's going to go in as NADH and it's going to come out as NAD positive.
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What happened in this reaction that NADH got oxidized into NAD positive?
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You know inside of here, there's actually going to be specifically a flavin mononucleotide.
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So here we're going to have this thing called a flavin mononucleotide
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that Flavin mononucleotide is going to pick up those electrons off of the NADH.
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And then it's going to get converted into Flavin mononucleotide, which is carrying the actual electrons.
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So this is going to be the Flavin mononucleotide carrying the electrons.
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And then it can also pass it on to iron sulfur clusters.
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But specifically, what's happening at this first step here?
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NADH is getting oxidized to NAD positive.
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And then flavin mononucleotide is getting reduced into flavin mononucleotide with the electrons.
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Then what happens?
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This flavin mononucleotide will react with this guy over here.
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This guy over here is going to be called coenzyme Q.
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So look what we have here.
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I have coenzyme Q.
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Coenzyme Q is going to come and react with that FMNH2.
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Look what happens.
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He is actually going to pick up the electrons from this FmNH2.
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When he picks up the electrons from the FmNH2 he gets converted into coenzyme Q and specifically they call it H2.
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So again what happened here in this first part,
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NADH dropped off its electrons to the FmN who got converted into FmNH2 which is the reduced form of Flavon Mononucleotide.
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That Flavin mononucleotide he passes the electrons onto coenzyme Q which gives you the reduced form of coenzyme Q.
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And then he'll take these actual electrons and pass them on to the next step.
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Before we do that, now let's see how FADH2 is doing this.
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Okay, because now we got to look at how exactly FADH2 is performing this function.
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Okay, FADH2 is going to come to this one right here.
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So let's show FADH2 coming up over here.
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FADH2 is going to come onto this actual, the specific component of the electron transport chain.
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And what it's going to do is it's going to drop off his electrons.
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He's going to drop off his electrons.
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And when he drops off his electrons, what would he come out as?
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He would come out as FAD.
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So he gets oxidized.
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When he gets oxidized, who gets reduced?
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If you remember again, over here I'm going to have the Flavin mononucleotide.
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He's going to pick up those electrons and get converted into Flavin mononucleotide, which is in the reduced form with the actual electrons.
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Then what happens?
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Look what else I have over here.
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You know this guy right here, this Q, this coenzyme Q, you know he's a mobile molecule.
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He's also not made of protein either.
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He's one of the only ones throughout this entire electron transport chain that's not made of protein.
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He is actually mobile along the membrane.
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So he can run ahead.
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And as he runs ahead, he gets over here.
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And now look at him.
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Coenzyme Q right here, he's like, hey, FMNH2, give me those electrons.
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I'll take care of them.
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And he gets converted into the reduced form of coenzyme Q, which is QH2.
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Okay?
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So what has happened so far with the FADH2's and NADH's?
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NADH dropped his electrons off onto this first complex.
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You know that's what we call it?
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We call this specifically, you know what we call this first one?
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This has two names.
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I can either call this complex 1 or I can call this NADH dehydrogenase because what did I tell you guys?
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Anytime you have NADH being dealt with, what do you know is going to be there?
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A dehydrogenase enzyme.
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So there's going to be an NADH dehydrogenase or you can also call this one complex 1.
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Then where did these electrons go from complex 1 or the NADH dehydrogenase?
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They get passed on to coenzyme Q and then coenzyme Q gets reduced.
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So this is actually going to be specifically.
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What's this molecule here called?
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This guy right here is called coenzyme Q.
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And sometimes you might even see it written as coenzyme Q 10.
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Okay?
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Then this coenzyme Q, where is he going to pass those electrons?
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We didn't talk about that yet.
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We're almost getting there.
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Before we do that, let's see what happened with the FADH2.
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FADH2 dropped his electrons off into this second complex if you will.
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So what is this guy here called?
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This is actually going to have two names again.
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I can call this one specifically.
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I'm going to call this one succinate dehydrogenase or they can also call it specifically complex II.
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Now complex II or succinate dehydrogenase is going to do what?
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It's going to take the FADH2 and convert it into FAD.
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Doesn't this enzyme sound familiar?
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Do you remember this enzyme guys?
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it was actually occurring here in the Krebs cycle.
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Remember when you were taking succinate and you were converting it into fumariate?
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What was it doing?
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It was taking FAD and converting it into FADH2.
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But remember I told you it's not a heavily regulated step.
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So what does that mean?
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It's reversible.
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So this is the enzyme
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that's actually going to be involved in the Krebs cycle as well as in the electron transport chain.
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Now, before I move on, I want to explain something with respect to complex 1 or NADH dehydrogenase.
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But I have to do it with a graph.
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So let's say over here I have a graph.
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And on the y -axis it's measuring energy.
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And on the actual x -axis it's like the reaction progress.
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Okay.
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Let's say I take this first NADH dehydrogenase.
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and he's sitting here at lower energy and I take the electrons from the NADH and I pass it on to him.
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If I pass that on to him, he's going to go to high energies.
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Who is this one?
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This is complex one or the NADH dehydrogenase enzyme, right?
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The complex.
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When this actual enzyme complex one goes to high energy levels, it doesn't prefer it.
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It doesn't like to be at high energy levels.
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He doesn't like that.
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No one likes to be at high energy levels.
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So what he decides to do is he decides, I don't want these electrons.
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I'm going to pass these electrons onto someone else.
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And when he does that, he loses the energy and he goes back down to low energy levels.
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Okay, well when he goes down to low energy levels from passing what?
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Passing the electrons away.
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What happens?
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He has a special type of pore.
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So let's say here is a component of this actual enzyme complex.
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Look over here.
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It has a pore.
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And on this pore, it can do something really special.
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What was NADH again?
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It was consisting of hydrides.
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What's a hydride?
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It's a proton and two electrons.
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All we did was pass electrons onto this complex I.
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Where'd the protons go?
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These protons are going to get pumped out.
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Okay?
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And it's going to get pumped from the actual mitochondrial matrix into the intermembrane space.
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And what allows for this?
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Whenever the electrons from complex I is getting passed onto coenzyme Q.
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Now, coenzyme Q takes these electrons and he'll pass it on to someone else which we haven't talked to yet.
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But what about complex II?
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Let's say here I have complex II.
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Complex II is going to get these electrons from FADH2.
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He's going to go to high energy levels.
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When he goes to high energy levels, he doesn't like it, so he passes it on to the other coenzyme Q,
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and it goes back down to low energy levels.
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but look he doesn't have a pore he doesn't have a protein component
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that will pump the protons out
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so no protons are getting pumped out through the actual mitochondrial matrix
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and into the inner membrane space at complex two
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or succinate dehydrogenase only complex one okay now it's time
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that we explain this next part so this QH2 that coenzyme QH2
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which is in the reduced form what's he going to do?
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He's going to take those electrons and he's going to pass those electrons onto this other coenzyme Q here.
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So he's going to pass these electrons onto that coenzyme Q and help to form another QH2.
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Who else is doing that?
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This FADH2 is giving
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it to FMN who's getting converted into FMNH2 who's also helping to convert coenzyme Q into the reduced form of coenzyme Q.
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And again, what is this molecule here called?
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This right here is specifically called Coenzyme Q10, right?
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Or Ubiquinone, they even call it Ubiquinone.
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Now, what happens with this Ubiquinone?
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Well now he's going to take those electrons and pass it on to the next guy.
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This is Complex 3.
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So now we're going to go into the next one which is going to be specifically Complex 3.
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But you know they have another name for Complex 3?
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So this is Complex 3. But they also call
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Complex 3 something else.
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They also call complex 3 a weird name.
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It's called coenzyme Q cytochrome B oxyoreductase.
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Okay, so again, what is the name of this?
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Coenzyme Q cytochrome B oxyoreductase.
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That is its name, or you can even call it Cytochrome BC1.
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complex or you can just call complex 3.
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It's up to you guys.
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Alright, but anyway what's happening here?
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You have this cytochrome and you know cytochromes are interesting because they're basically kind of like heme groups.
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They have a porphyrin component of them which is like a pigment as well as having some type of
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usually an atom or mineral or specifically a metal in the center component of it.
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In this case it's iron.
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So let's say I have here cytochrome B and I draw here cytochrome B.
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And the cytochrome B specifically has iron here and it can have an iron here.
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Now what happens is, is this coenzyme QH2, right, it's going to pass these electrons onto the cytochrome B.
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When it passes the electrons onto the cytochrome B, who is it specifically going to pass it on?
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Well you know iron can exist in two states, right?
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So let's say that he passes these electrons over here.
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And when he does that, this guy gets converted right back into his original state because he's giving those electrons away.
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He's going to accept these electrons.
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When he accepts these electrons he's going to get turned into a different oxidation state.
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You know what state he's going to be in here?
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It's going to be plus three.
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If he gains an electron one at a time right, what would it become?
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Plus two.
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So specifically what's happening is that coenzyme QH2 is passing this electron onto Fe plus three
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and Fe plus three is getting converted into Fe plus two because he's accepting that electron.
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Now, same thing like before.
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Let's say I have this graph here.
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I keep extending my graph.
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If I keep extending my graph now, what's this enzyme complex 3 going to be at before it accepts the electrons at low energy?
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But then it accepts that electron.
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And when it accepts those electrons, it goes to high energy.
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He doesn't like it.
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What is he going to do?
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He's going to pass the electrons onto the next guy, which is going to bring him down into low energy.
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You know what's special about this guy just like complex one?
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He has another channel off the side.
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And off to the side of this guy he's got this little pore.
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And you know what this pore is going to be doing?
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It's going to be pumping protons out here into the intermembrane space from the mitochondria majors.
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Because you know there's going to be protons which are going to be concentrated in this area right?
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The concentration in here, you're going to have a lot of protons in here too.
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Usually its concentration in this area is usually around 10 to the negative 9, right?
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And specifically this might be in millimolarity, right?
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So you're going to have some type of concentration in here.
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And usually before these protons are getting pumped out into this area, it's also about 10 to the negative 9 millimolarity.
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So usually they're pretty much equal before you start pumping tons of protons out.
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We'll see how it changes.
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But it's pumping these protons out into the actual intermembrane space.
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At what point?
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At complex III and at complex I.
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Or you can also call complex III cytochrome Q, specifically coenzyme Q cytochrome B, oxyoreductase.
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Then what happens?
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This guy right here is going to pass his electrons on to the next guy.
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Okay, who is this next guy?
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This guy right here is specifically going to be called cytochrome C.
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So this is called cytochrome C.
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So they call it cytochrome C.
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So what cytochrome C is consisting of is still the same.
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It's going to have that heme group in it, right?
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So here let's say you have your cytochrome C.
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And again it's going to have iron in it.
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And it might even have copper as well incorporated into it also.
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But again, what's happening?
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This iron passes electrons onto this Fe2+.
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This Fe2 is at high energy states.
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He doesn't want to have those electrons anymore.
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What is he going to do?
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He's going to take and pass those electrons onto this guy.
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So now look what happens.
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These electrons are going to get passed over onto this guy and he's going to get regenerated back into Fe3+.
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When he does that, this guy is now going to do what?
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Well specifically, let's say that we do the same thing.
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Let's say that this iron right here reacts with that and picks up those electrons.
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If he picks up those electrons, what state should he be in?
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He should be in the plus three state.
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When he accepts those electrons, he should now go into the plus two state.
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And again, you can have copper as a component of this cytochrome too.
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Then what happens?
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Then we go on to the last one.
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At the last one we have it called as complex four.
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Or, like always, it can also have another name,
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they also call this cytochrome oxidase.
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And you'll see why they call it oxidase.
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This is a very, very important complex.
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Okay, now, same thing.
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It's going to become redundant here.
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And I know this is going to be specifically this cytochrome oxidase is actually consisting of cytochromes, but specifically cytochrome A and also A3.
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So cytochrome A plus A3.
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So it consists of these two cytochromes in its actual enzyme complex.
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And once again, this cytochrome A plus A3 is going to be consisting of iron. And what's happening here?
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This iron is in the plus two state.
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So if he's at the plus two state he's not gonna like that.
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He's at high energy status.
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He doesn't want to be high energy status.
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He's gonna take those electrons and pass it on to the next guy.
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It's just like a game of hot potato, right?
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I don't want it.
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Who am I?
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I'm enzyme complex one.
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I'm gonna give it to the next guy, coenzyme Q.
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Coenzyme Q doesn't want it.
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He gives it to another coenzyme Q.
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Q doesn't want it.
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He gives it to coenzyme Q.
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Q gives it to who?
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Cytochrome B.
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Cytochrome B gives it to, cytochrome C and cytochrome C gives it to this actual cytochrome oxidase.
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And it's just a game of hot potato all the way down.
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Now, when this guy passes his electrons back over here,
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because now look, he's going to come from here and he's going to pass these electrons back over to this guy.
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What do you think this guy's going to do?
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Same thing.
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He's going to pick and accept those electrons.
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When this iron, which is going to be, again, redundancy, plus three, he goes back into the plus two state.
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He accepts those electrons.
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Then what happens?
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Something very, very interesting happens electrons.
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You know in this area I'm going to have specifically I'm going to have oxygen.
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So I'll have oxygen out here.
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So let's say here I have some oxygen and specifically it's the atomic oxygen.
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So if I put one half of an oxygen that's just specifically atomic oxygen.
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That one half of an oxygen is going to react with this iron in the plus three state
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and this iron in the plus two state.
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Specifically the plus two state one.
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So as Once this iron in the plus two state is going back to the plus three state, he's giving his electrons to who?
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He's giving it to this oxygen.
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This oxygen is then going to pick up those electrons from that plus two iron.
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You know what else is going to get combined in there?
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Two protons.
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So now these two protons are going to get combined with the half of an oxygen.
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So you're going to have one half of an oxygen taking
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up these electrons from the plus two iron in the cytochrome A plus A3 going back to plus three.
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he's going to accept those electrons, combine with two protons and make water.
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Oh man, it's beautiful.
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So what happened here then?
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I took half of an oxygen, two H pluses, and I accepted those electrons.
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Those electrons go anywhere else?
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No. That means that this oxygen is the final electron acceptor.
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So when hot potato, hot potato, hot potato, and then gave it to oxygen, and he just accepted it and he's like,
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okay, I'll take the potato, right?
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So he is going to be the last one of the electron transport chain accepting those electrons.
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So now, before we go back over here and review this, one more thing happens.
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Just like this guy, let's come back to this graph.
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This complex 4 is at low energy levels, but then what happens?
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When this complex 4 accepts the electrons from this cytochrome C, right, the plus 2 iron is giving the electrons to the cytochrome A plus A3,
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he's accepting those electrons and going to high energy levels.
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Does any molecule
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Do people prefer high energy levels?
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No. So what does he do?
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He gives those electrons to who?
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To the oxygen and then the protons to make water.
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When he passes those electrons away, his energy levels go back down.
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That energy is harvested to do what?
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Look what happens here.
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What do you think I have right here into this membrane?
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I have a little channel.
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And guess what I'm going to pump out of this sucker right here?
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I'm going to pump out a proton.
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So I'm going to take a proton and I'm going to pump that proton where?
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From the intermembrane space into the, I'm sorry, from the mitochondrial matrix into the intermembrane space.
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So now, let's review from beginning to end what's actually happening.
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So where do we start?
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We started at complex 1 or, again, NADH dehydrogenase.
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The NADH is dropping the electrons off to this complex 1, specifically the flavin mononucleotide.
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And also, just remember, I'm going to write it down.
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technically this Flavon mononucleotide is passing the electrons before it goes to coenzyme Q, it's passing it to a lot of iron sulfur cluster proteins.
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It's not significant in this concept, just know that it's passing it to a lot of iron sulfur cluster proteins.
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Anyway, once this NADH passes electrons it goes to NAD positive
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and then this FNN gets converted into the reduced form of FNN
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and technically this FNN
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or reduced form is going to pass it on to a bunch of iron sulfur cluster proteins
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which is this then going to pass those electrons on to who?
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Specifically it's going to pass it on to coenzyme Q.
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Coenzyme Q is going to be a mobile specifically what it's a mobile electron transport chain component
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but it's not made of protein.
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The coenzyme Q is going to accept those electrons
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and get converted into the reduced form of coenzyme Q
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and he'll pass those electrons on to another non -reduced form
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of coenzyme Q to make the reduced form of coenzyme Q because he is able to be mobile.
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He can be throughout this actual intermitochondrial membrane.
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At the same time that's happening FADH2 is also being converted into FAD.
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He's getting oxidized.
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Who's picking up those electrons?
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The flavin mononucleotide and the enzyme component of succinate dehydrogenase.
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And then it's getting converted into the reduced form of flavin mononucleotide.
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Okay and this also consists of some different types of iron sulfur cluster proteins.
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But then what happens to this reduced form of flavin mononucleotide.
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The coenzyme Q is going to pick up those electrons and get converted into the reduced form of coenzyme Q.
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Also remember at complex one what was happening when this electrons were getting passed over.
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It was pumping a proton out.
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Then these electrons from the actual complex two where the succinate
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dehydrogenase gets passed on to specifically coenzyme Q here also coming from the coenzyme Q before,
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this coenzyme Q is going to react with Q cytochrome B oxyoreductase
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or you can call it cytochrome BC1 complex or you can just call it complex 3 specifically.
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What's happening here?
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This cytochrome B is consisting of iron and this iron components here are going to be accepting the electrons. Which one?
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Iron in the plus 3 state is going going to accept the electrons from the coenzyme Q
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and go into the plus two state.
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Then it's going to take those electrons
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and pass it on to another iron who's going to be in the plus three state,
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so it can go into the plus two state in the component of cytochrome C.
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But when it passes those electrons over to the cytochrome C,
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he goes from high energy to low energy and pumps out a proton from the mitochondrial matrix into the intermembrane space.
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Then the cytochrome C is going to do what?
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When it accepts those electrons, it goes from the plus three iron state to the plus two iron state
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and then again it goes to high energy doesn't want it passes electrons on to cytochrome oxidase
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or enzyme complex 4
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which is consisting of cytochrome a plus a3 then what happens this is also consisting of iron
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and he accepts those electrons from the cytochrome C
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and goes from the plus 3 state to the plus 2
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state doesn't want those electrons to high energy what does he
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do he passes electrons on to oxygen who's the final electron
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acceptor who who will then combine with two protons to make water.
450
But when he goes from the plus two back to the plus three, back to low energy levels,
451
it creates, opens up this pore to push a proton out.
452
So again, at what points here are we actually pushing the protons out?
453
Specifically, we're pumping a proton out at complex one, we're not pumping a proton out at complex two, we're pumping a proton out at complex three,
454
and we're pumping a proton out at complex four.
455
And this is due again to whenever it's from high energy transitioning to lower energy.
456
Now, as all of this is happening, what's happening to the proton concentration out here now?
457
Now we can go in and explain to this next part at least for a second.
458
Now the proton concentration out here is going to be much higher than the proton concentration in the mitochondria matrix.
459
Because we're pumping tons of protons out here.
460
This proton concentration can go up until about 10 to the negative 7.
461
millimolar whereas what was it in compared in the mitochondrial matrix it was about 10 to the negative 9 millimolar
462
so now there's actually a two -fold increase in the protons out here in the intermembrane space
463
and this establishes what's called a concentration gradient and we'll talk about
464
that in a second so now what's the problem though we're not done yet
465
and you want to know why we took care of the NADH is from the Krebs cycle these six NADH
466
and we took care of the two NADH is from the transition step
467
and we took care of the two AFADH2's from the Krebs cycle.
468
But what NADH's have we not accounted for yet?
469
These suckers right here.
470
Now we have to figure out, because here's the problem, NADH can't just cross the mitochondrial membrane.
471
It has to have a special obviously complex way to get in and then drop those electrons off.
472
That's what we're gonna do in the next video.
473
So in the next video we're just gonna continue on with the electron transport chain
474
but talking specifically about how these NADHs are getting into the mitochondria and doing these functions.
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Vocabulary and speaking notes for this lesson
The speaker keeps coming back to these words: electron, complex, coenzyme, cytochrome, Nadh. This video has 474 sentences and 5062 words to shadow. The speech runs for 29:13. The speaker talks at a natural 173 words per minute, close to everyday conversation. Only 80% of the words are among the 3,000 most common in English, so the vocabulary is demanding. 102 of its 474 sentences are questions, so it is good practice for question intonation and short answers.
Key vocabulary in this video
15 words from the video worth learning, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| electrons noun | The digital or electronic version of a document. | |
| convert verb | /kənˈvɝt/ | To transform or change (something) into another form, substance, state, or product. |
| membrane noun | /ˈmɛm.bɹeɪn/ | A mechanical, thin, flat flexible part that can deform or vibrate when excited by an external force. |
| pump noun | /pʌmp/ | A device for moving or compressing a liquid or gas. |
| electron noun | /ɪˈlɛk.tɹɑn/ | The subatomic particle having a negative charge and orbiting the nucleus; the flow of electrons in a conductor constitutes electricity. |
| oxygen noun | /ˈɑksɪd͡ʒən/ | The chemical element (symbol O) with an atomic number of 8 and relative atomic mass of 15.9994. It is a colorless and odorless gas. Sometimes called elemental… |
| enzyme noun | /ˈɛn.zaɪm/ | A biomolecule that catalyses a biological chemical reaction: either a globular protein with this function or an RNA molecule with this function. |
| component noun | /kəmˈpoʊ.nənt/ | A smaller, self-contained part of a larger entity. Often refers to a manufactured object that is part of a larger device. |
| generate verb | /ˈd͡ʒɛn.ə.ɹeɪt/ | To bring into being; give rise to. |
| matrix noun | /ˈmeɪ.tɹɪks/ | The cavity or mold in which anything is formed. |
| consist noun | /kənˈsɪst/ | A lineup or sequence of railroad carriages or cars, with or without a locomotive, that form a unit. |
| concentration noun | /ˌkɑn.sənˈtɹeɪ.ʃən/ | The act, process or ability of concentrating; the process of becoming concentrated, or the state of being concentrated. |
| react verb | /ɹiːˈækt/ | To act in response. |
| molecule noun | /ˈmɑ.lɪ.kjul/ | The smallest particle of a specific element or compound that retains the chemical properties of that element or compound; two or more atoms held together by… |
| potato noun | /pəˈteɪ.təʊ/ | The edible starchy tuber of the plant species Solanum tuberosum. |
Phrasal verbs you will hear
| Word | Pronunciation | Meaning |
|---|---|---|
| pick up verb | To lift; to grasp and raise. | |
| drop off verb | To fall asleep. | |
| come out verb | /ˌkʌm ˈaʊt/ | To be discovered; to be revealed. |
| go back verb | To return to a place or state after having been there at a previous time. | |
| go back to verb | To stem from; to originate in. | |
| run ahead verb | To use sidings to pass a different train. | |
| figure out verb | To come to understand; to discover or find a solution; to deduce. | |
| get over verb | To overcome. |
Sentences worth repeating
Short, complete lines from the video that you can reuse in everyday conversation:
- You see how it's really, really folded?
- How do you say that?
- What's a hydride ion, if you guys remember quickly?
- You know that's what we call it?
- What do you think this guy's going to do?
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Passive voice be + past participle — the focus is on what happens, not who does it | is called · be folded · is folded |
| Relative clauses who / which + clause — extra information about a person or thing | mitochondria, which is · membrane which is · mitochondria which is |
| Present perfect have/has + past participle — a past action that still matters now | you've seen · we've already done · has happened |
Pronunciation to watch
The speaker uses 81 contractions and reduced forms, such as we're, doesn't, I'm. Say them the short way, as you hear them.
- The “sh” and “zh” sounds: concentration /ˌkɑn.sənˈtɹeɪ.ʃən/, transition /tɹænˈzɪʃ.ən/, establish /ɪˈstæb.lɪʃ/, conversion /kənˈvɝʒən/, shuttle /ˈʃʌtəl/
- Long words — get the stress right: concentration /ˌkɑn.sənˈtɹeɪ.ʃən/, technically /ˈtɛk.nɪˌkəl.i/, mechanism /ˈmɛk.ə.nɪ.zəm/, significance /sɪɡˈnɪfɪkəns/, incorporate /ɪŋˈkɔɹ.pɚ.eɪt/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like electrons, convert, membrane.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.