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  • Hi. It's Mr. Andersen and this is AP Biology Science Practice 1. What are

    こんにちは、アンダーセンです。 今回はAP生物科学の練習問題1です。これは何ですか?

  • science practices? Well there are seven of them. And they're overarching skills and knowledge


  • that you should have to do well as a scientist. Why is that important in an AP Bio class?


  • Well if you're a teacher, if your'e an AP Biology instructor, practices are skills and


  • knowledge that you want to build in your students throughout the year. And if you're a student,


  • these are the practices that you want to pick up. Because when you take the AP Biology test


  • in the spring, they're going to ask you to apply the knowledge that you've picked up


  • throughout the year using science practices. And so you want to understand what a model


  • and what a visual representation is, because it's going to allow you to do better on the


  • test. And it could also allow you to do better as a scientist. And this right here is a picture


  • of DNA. So this is bacterial DNA under an electron microscope. And you might fool yourself

    のDNAです。これが電子顕微鏡で見た 細菌のDNAなんですねそして、あなたは自分を騙すかもしれませんが

  • into thinking that we're looking at the double helix. That we're looking at DNA. But that's

    二重らせんを見ていると 思わせてしまいますDNAを見ているということですしかし、それは

  • not really what it is. If we zoom in as close as we can see, that's not what we see. In

    本当の姿ではありません見える限り拡大してみると それは本当の姿ではありません望遠鏡の中では

  • fact the DNA is wrapped around histone proteins which are wrapped around more DNA and more


  • histone proteins. And we eventually get to something that looks like this. We call it


  • a fiber of DNA and that's what you're looking at in this picture. And so it's weird to think

    この写真で見ているのは DNAの繊維ですこの写真を見ているのはこれです。

  • that we've never seen a double helix. We've never seen DNA at this level, especially at


  • this level. And so how do we know that that's what it looks like? Through careful experimentation.


  • Watson and Crick developed a model. And a model is going to allow us to understand how

    ワトソンとリックは モデルを開発したモデルを作ることで

  • DNA works. It's a visual representation of what's going on inside the genetic material


  • of a cell. And so if I were to ask you, think about this, how is the DNA eventually become

    細胞のそこで考えてみてください DNAは最終的にどのようにして

  • a protein in a cell? Well in your brain you're going to start coming up with all of these


  • mental models of how the DNA maybe becomes messenger RNA and then is somehow translated


  • in the cytoplasm. That's your mental model. But it's still not a model. It's still not


  • a visual representation because it's not shared by everyone. And so once we have a picture

    誰もが共有できるものではないので 視覚的な表現になりますだから、一度絵を手に入れたら

  • of how it works, now we're at the level of a conceptual model and that's what this science


  • practice is really about. And so throughout AP Biology, remember there are four big ideas


  • that we're going to talk about. Evolution, Free Energy, Information and then finally


  • Systems. And I came up with four models that would be typical in each of these different


  • big ideas. And so if we're talking about evolution, this is a nice model that shows natural selection.


  • So we've got bacteria, we've got a selective process when we're choosing these bacteria


  • and then this is a finally population. And maybe we're thinking about bacteria and so


  • this is resistance levels. And so the ones that are able to survive are going to be the


  • ones that have the highest resistance. And so by visually making natural selection apparent


  • to us, it's easier to deal with questions. Or let's say we're looking at free energy


  • and how free energy is transferred. This is a nice visual representation of photosynthesis.


  • So it shows the light reaction in the Calvin Cycle. It shows the reactants and the products


  • of each. And it also shows these carrier molecules of NADPH and ATP. What if we're looking at


  • information flow? Remember that deals with things like genetics and cell communication.


  • This would be a great example of a model. This shows you how an operon works. And so


  • this is going to be our RNA polymerase and we have a repressor here. Or maybe if we're


  • looking at systems a great model could be this pyramid of energy showing carnivores,


  • herbivores and plants. And so this gives you an idea of what a model looks like. And how


  • it can be applied in an AP Biology class. But they're asking that you can do five things


  • using models and visual representations. And so they first of all want you to be able to


  • create models and representations. And so you can think of each of these questions,


  • where's the first one, like a question you might experience on the AP Biology test in


  • the spring. In other words they're asking you to apply the knowledge that you've built


  • using a science practice. In this case you would have to build or create a model of representation.

    理科の実習を使ってこの場合は 表現のモデルを作るか作成する必要があります

  • And so you could pause the video, I've got five of these, and you could try to do this


  • and then you could watch me explain it. And so pause the video now and let me go through


  • it. So we've got a hypothetical population of beetles. There's wide variation in color


  • matching the range of coloration of the tree trunks. Create a graph that show how the beetle


  • population would change as a result in changes in the environment that darken the tree trunks.


  • And so what are some first things that I would look at? So we've got a beetle population.


  • There's differences in color. But they're saying that we have a variety of different


  • colors. And so we're going to represent that with a graph. We want to show the frequencies,


  • but we're going to have a normal distribution. In other words we could be put beetle color


  • here along the x axis, from light to dark and we're going to get a normal distribution.


  • In other words some of the beetles are really light. Some are really dark. But most of them


  • are going to be in the middle. What are they then asking us to do? They want to show us


  • evolution. They want to show us how they're changing as the bark becomes darker and darker.


  • So what's going to happen? Well as the bark becomes darker and darker, all of these lightly


  • colored beetles are going to die because the birds are going to see them. And they're going


  • to show up. And so they're going to die on this side of that curve. And so this would


  • be pre-evolution and then this would be post-evolution. And so what we're going to see is directional


  • selection. And so it's neat. I could look at that. We now have a visual representation


  • of a concept and this is what they're getting at. Can you build a model like this? Or, if

    概念の中にあるもので これが彼らが得ているものですこのようなモデルを作ることはできますか?とか、もし

  • you were given four options in a multiple choice portion, could you choose the one that


  • reflects this hypothetical change? Let's go to the next thing they'd like you to be able


  • to do. They want you to be able to describe a model or a visual representation. Well here's


  • a question. What will happen to the water molecules in dissolved salts over time? So

    という質問がありました。溶解した塩の水分子は 時間が経つとどうなるのでしょうか?ということで

  • we have a U-tube over here on the side. You could look right here that we've got water,


  • which is going to be this bluish color and we have these dissolved salts. And so they're


  • going to ask you what would happen over time? One other piece of evidence is that we've

    時間が経てば何が起こるかを 尋ねるつもりですか?もう一つの証拠として、私たちは

  • got a semi permeable membrane down here. What does that mean? It's only going to allow certain


  • things through. In this case it's only going to allow water to go through. So what would


  • happen over time? Well we're now dealing with diffusion. And so these salt molecules are


  • going to be randomly bouncing around and they would always want to move from an area of


  • high concentration to low concentration. They would always want to move from the left side


  • of the U-tube to the right side of the U-tube. But they can't, because there's a semi permeable


  • membrane here. And so the water is the only thing that can move. So let's look at the


  • water now. Well the water is going to have a higher concentration of water on the right


  • side then the left side. And so the water is going to start flowing through this semi


  • permeable membrane. So the level of the water would magically move up on this side and it's


  • going to move down on this side. How long is it going to do that? Until the concentration


  • of salt molecules to water molecules is going to be the same on either side. Now does the


  • water stop moving? No. It's still going to move back and forth, it's just that it's going


  • to be at an equilibrium. So you can see now that I'm giving you a model and then I'm asking


  • you to describe the model or what's going to happen over time. The third thing they


  • want you to be able to do in this science practice is to refine a model or representation.


  • And so they could give you a model and then they could ask you questions based on that.


  • So I've got a model over here to the right and what I'm asking is how will changes in


  • the messenger RNA sequence effect the properties of the newly born protein? Okay now I'm asking


  • you to refine the model that I have given you. And so right here you can see that we've


  • got translation going on. So we've got messenger RNA. It's moving through a ribosome. And as


  • it does, we've got our tRNA. So the tRNA, which is going to be this molecule right here


  • is going to arrive at the A site and it's going to contribute it's one amino acid. And

    はAサイトに到着して 1つのアミノ酸に貢献することになりますであり

  • so that would be just describing this model. But they want you to refine it. In other words,

    それはこのモデルを説明しているだけでしょうしかし 彼らはそれを改良して欲しいと言っています言い換えれば

  • what would happen if we would change the messenger RNA sequence? Well if we change that sequence

    メッセンジャーRNAの配列を変えると どうなるのでしょうか?その配列を変えると

  • here, it's going to change the amino acids that come in and therefor it's going to change


  • the proteins. What's going to happen if we change the proteins? Well remember, or excuse


  • me, the amino acids? Every amino acids is going to be the same except for the R group


  • that hangs off to the side. And so if we change those R groups, we're going to change the


  • chemical interactions between all of those R groups and so we're going to get a protein


  • that folds differently. In other words its secondary and tertiary structure is going


  • to be different. And so now I'm not answering a question based on this model, I'm saying


  • if we could refine it what else do I know. Next thing they want you to be able to do


  • is use models and representations. And so right here they're saying the digram to the


  • right shows transduction in bacteria. How does genetic variation in bacteria result


  • from this process? So they're going to ask you to use the model. In this case we've got


  • a bacteriophage, remember it's a virus that's infecting a bacteria. But that's not what

    バクテリオファージを覚えておいてください バクテリアに感染しているウイルスですしかし、それは

  • the question is about. They're asking you to say how that would effect the genetic variation


  • in the bacteria. Now remember, bacteria don't have sex. They don't do meiosis and produce


  • sperm and egg. And so how could we get variation in it? Well let's look at what's going on.


  • So the bacteria is injected with DNA from the bacteriophage. That's basically programming


  • that bacteria to make more viruses. Except there's one thing going on right here. At


  • this point, instead of this virus being packaged with viral DNA that's created by the bacteria,


  • it's packaged with bacterial DNA. And so as these viruses spread out, this one virus is

    それはバクテリアのDNAと一緒に 包み込まれていますそれで、これらのウイルスが拡散していくと、この1つのウイルスは

  • injecting bacterial DNA into another bacteria. So it's transferring DNA from one bacteria


  • to another. What is that going to give that new bacteria? It's going to give it variation.


  • And so again I'm applying my knowledge to a model or a visual representation. And then


  • the last one is we need to be able to reexpress models and representations. And so in this


  • one we're looking at signal transduction. So you can see right here that we've got an


  • insulin receptor and then we've got glut or we've got a glucose transport. So what's the


  • question asking? How can changes in key elements of signal transduction alter cellular response?


  • And so again now they're asking you to apply the knowledge that you have. In this case,


  • why is insulin important? Insulin is going to dock with an insulin receptor, but what


  • it's really going to open up are going to be these glucose transports. In other words


  • it's going to open up this gate and so glucose can get into the cell. And so what are some

    このゲートを開くことで グルコースが細胞内に入ることができますそれで、いくつかの

  • questions we can ask from that? Well let's say there's no insulin. If there's no insulin


  • here, there's going to be no signal transduction and it's not going to open up and it's not


  • going to allow glucose to come in. So if you're a type I diabetic, if you don't have insulin,

    ブドウ糖が入ってくることを許してしまうのです。もしあなたが1型糖尿病なら インスリンを持っていなければ

  • they you're out of luck. But let's say you're a type II diabetic. Where's the problem going

    彼らはあなたが運がないと言っていますしかし あなたがII型糖尿病患者だとしましょうどこに問題があるのか

  • to be there? Now we've got a problem with the insulin receptor itself. We're creating


  • insulin but it's not docking properly with the insulin receptor. What's that going to

    インスリンだけど インスリン受容体と適切に結合していませんそれは何をするのかというと

  • do? We still don't have a signal transduction. We still don't have a glucose transport opening


  • up. And so again these are all questions that you might find on an AP Biology test in the


  • spring. In other words they're asking you to use models, create models. But models are


  • neat. They allow us to make sense of a mental model. And lots of times it gets visual and


  • it gets much easier to understand. And they're used by scientists. What's the most famous


  • model of all? That model was developed by James Watson and Francis Crick, right here.

    全てのモデル?そのモデルは ジェームズ・ワトソンと フランシス・クリックによって開発されました ここにあります

  • They're shaking hands with McCarty, who is one of the scientists who had figured out


  • that is was DNA that was actually doing the transforming inside bacteria. But they were

    それは実際にバクテリアの中で 形質転換をしていたDNAでしたしかし 彼らは

  • able to build a model. They were able to build a model because they knew what DNA was made

    模型を作ることができました。彼らがモデルを作ることができたのは DNAがどのように作られているかを知っていたからです

  • up of. They knew that it was made up of phosphates, sugar and then these nitrogenous bases. They