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

科學實踐？嗯，有七種。而他們'的總體技能和知識。

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

作為一個科學家，你應該有做得好的。為什麼在AP生物課上很重要？

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

好吧，如果你'是一個老師，如果你的'e AP生物教師，實踐是技能和。

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

的知識，你要建立在你的學生在整個一年。而如果你'是一個學生。

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

這些都是你要學會的做法。因為當你參加AP生物考試的時候

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

在春天，他們會要求你應用你所學到的知識。

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

全年使用科學實踐。所以你要了解什麼是模型

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

以及什麼是視覺表現，因為它將讓你做得更好。

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

測試。而且它還可以讓你更好地做一個科學家。而這是一張圖片

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

的DNA。所以這是電子顯微鏡下的細菌DNA。你可能會欺騙自己

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

以為我們在看雙螺旋。我們正在尋找DNA。但那是

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

不是真正的它是什麼。如果我們把它放大到我們能看到的近處，那'不是我們看到的。在

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

事實上，DNA被包裹在組蛋白上，而組蛋白包裹著更多的DNA和更多的。

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

組蛋白。我們最終得到的東西，看起來像這樣。我們稱它為

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

這就是你所看到的這張照片。所以它是奇怪的認為。

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

我們從未見過雙螺旋。我們從來沒有見過DNA在這個水準上，特別是在這個水準上。

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

這個級別。所以我們怎麼知道那是什麼樣子的呢？通過仔細的實驗。

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

沃森和克里克開發了一個模型。而模型可以讓我們瞭解到

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

DNA的工作原理。它是遺傳物質內部發生的事情的視覺表現

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

的細胞。所以，如果我問你，想想看，DNA是如何最終變得

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

細胞中的蛋白質？在你的大腦中，你會開始想出所有的這些東西

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

心智模型的DNA是如何也許成為信使RNA，然後以某種方式翻譯的

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

在細胞質中。那是你的心理模型。但它仍然不是一個模型。它仍然不是

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

一個可視化的表現，因為它'不是每個人都分享。所以一旦我們有一個圖片

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

現在，我們在一個概念模型的水準，這就是這個科學。

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

練習的真正意義。所以在整個AP生物中，要記住有四個大的理念

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

我們'要談的。進化，自由能源，資訊，然後最後

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

系統。我想出了四種模式，在這些不同的系統中，每一種模式都是典型的

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

大的想法。是以，如果我們'談論進化，這是一個很好的模型，表明自然選擇。

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

所以我們有細菌，我們有一個選擇的過程 當我們選擇這些細菌

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

然後這是一個終於的人口。而且也許我們'正在考慮細菌，所以

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

這就是阻力位。所以能夠生存下來的，都會是那些

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

抵抗力最高的。所以通過視覺上讓自然選擇變得明顯

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

對我們來說，它'更容易處理問題。或者說，我們'正在研究自由能源。

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

以及自由能量是如何轉移的。這是一個很好的光合作用的直觀表現。

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

所以它顯示了卡爾文循環中的光反應。它顯示了反應物和產物

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

的每個。而且它還顯示了NADPH和ATP的這些載體分子。如果我們在看

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

信息流？記住，涉及到遺傳學和細胞通信等方面。

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

這將是一個很好的模型的例子。這向你展示了一個操作子是如何工作的。所以...

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

這將是我們的RNA聚合酶，我們有一個抑制器在這裡。或者，也許如果我們&#39；是

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

從系統來看，一個偉大的模型可能是這個能量金字塔，顯示出食肉動物。

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

食草動物和植物所以這讓你知道一個模型是什麼樣子的。以及如何

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

它可以應用在AP生物課上。但他們要求你能做五件事。

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

使用模型和視覺表現。所以他們首先希望你能夠做到

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

創建模型和表徵。所以你可以思考每一個問題。

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

哪裡'的第一個，像一個問題，你可能會遇到AP生物測試在

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

的春天。換句話說，他們'要求你應用你所建立的知識。

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

使用科學實踐。在這種情況下，你將不得不建立或創建一個表示模型。

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

所以，你可以暫停視頻，我'已經得到了五個這些，你可以嘗試做到這一點。

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

然後你可以看我解釋。所以暫停視頻，現在讓我去通過。

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

所以我們有一個假設的甲蟲種群所以我們有一個假設的甲蟲群體。有寬廣的顏色變化

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

匹配樹幹的顏色範圍。創建一個圖表，顯示甲蟲如何。

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

由於環境的變化，樹幹變黑，種群會發生變化。

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

所以，什麼是一些首先的事情，我會看看嗎？ 是以，我們'已經得到了甲蟲的人口。所以，我們'已經得到了一個甲蟲人口。

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

有'的顏色差異。但他們'說，我們有各種不同的。

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

的顏色，所以我們'要用圖來表示。所以我們'要用圖形來表示。我們要顯示頻率。

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

但我們'要有一個正態分佈。換句話說，我們可以把甲蟲的顏色

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

這裡沿著X軸，從亮到暗，我們'將得到一個正態分佈。

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

換句話說，有些甲蟲真的很輕。有的真的很黑。但大部分的甲蟲

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

是要在中間。那麼他們要我們做什麼呢？他們想告訴我們

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

進化。他們想向我們展示它們是如何隨著樹皮變得越來越黑而變化的。

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

那麼會發生什麼呢'？好吧，隨著樹皮的顏色越來越深，所有這些淺淺的。

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

彩色甲蟲會死，因為鳥類會看到他們。而他們'要

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

來出現。所以他們'會死在曲線的這一邊。所以這將

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

是前進化，然後這將是後進化。所以，我們'要看到的是方向性的。

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

選擇。所以它'的整潔。我可以看看這個。我們現在有一個可視化的表示

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

的概念，這就是他們'的目的。你能建立一個這樣的模型嗎？或者，如果

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

在選擇題部分，你有四個選項，你能選擇那個

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

反映了這種假設的變化？讓我們去看下一件事，他們'希望你能。

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

來做。他們希望你能夠描述一個模型或視覺表現。好吧，這裡's

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

一個問題。溶解鹽中的水分子隨著時間的推移會發生什麼變化？所以

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

我們有一個U型管 在這裡的一側。你可以看看這裡，我們'已經得到了水。

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

這將是這個藍色和我們有這些溶解的鹽。所以他們

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

要問你隨著時間的推移會發生什麼？另外一個證據是，我們'已經。

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

這裡有一個半透膜。這是什麼意思？它只允許某些。

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

的東西通過。在這種情況下，它'的只會讓水通過。所以，什麼會

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

隨著時間的推移而發生？好吧，我們現在處理的是擴散。所以這些鹽分子

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

他們總是想從一個區域移動到另一個區域。

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

高濃度到低濃度。他們總是想從左邊移動到右邊

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

的U型管到U型管的右側。但他們不能，因為那裡有一個半透的

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

這裡的膜。所以水是唯一可以移動的東西。所以讓我們看看

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

現在的水。那麼水的濃度會比較高，右邊的水。

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

然後是左邊是以，水將開始流過這個半。

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

透水膜。所以，水位會神奇地在這邊移動起來，它的'。

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

要在這邊移動下來。它要做多久呢？直到濃度

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

鹽分子與水分子的比例在兩邊都是一樣的。現在是否

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

水停止移動？不，它仍然會來回移動，只是它的移動方式是

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

要在一個平衡點。所以，你現在可以看到，我給你一個模型，然後我問。

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

你來描述模型或隨著時間的推移會發生什麼'。第三件事，他們

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

希望你在這次科學實踐中能夠做到的是完善一個模型或表象。

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

所以他們可以給你一個模型，然後他們可以根據這個模型問你問題。

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

所以，我'已經得到了一個模型在這裡的權利，我'問的是如何將變化在。

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

信使RNA序列會影響新生蛋白質的特性嗎？好吧，現在我問

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

你來完善我給你的模型。所以在這裡你可以看到，我們''ve

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

得到了翻譯的事情。所以，我們已經得到了信使RNA。它的移動通過核糖體。而作為

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

它做，我們'已經得到了我們的tRNA。所以，tRNA，這將是 這個分子就在這裡。

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

是要到達A位點，它'的要貢獻它'的一個氨基酸。而

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

所以這只是在描述這個模型。但他們希望你能完善它。換句話說

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

如果我們改變信使RNA的序列會發生什麼？如果我們改變了這個序列

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

在這裡，它將改變氨基酸，進來 是以，它將改變。

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

蛋白質。如果我們改變蛋白質，會發生什麼？好吧，記住，或原諒

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

我，氨基酸？每個氨基酸都是一樣的，除了R基團之外

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

懸掛在一邊。是以，如果我們改變這些R組，我們'要改變的。

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

所有這些R基團之間的化學相互作用，所以我們'將得到一個蛋白質的

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

的摺疊方式不同。換句話說，它的二級和三級結構是去

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

要不同。所以現在我'不是根據這個模型來回答問題，我'說的是

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

如果我們能改進它，我還知道什麼。他們希望你能做的下一件事是：

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

是使用模型和表示。所以就在這裡，他們'說digram到的。

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

右圖為細菌中的轉導。細菌的遺傳變異是如何導致的

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

從這個過程中?所以他們'會要求你使用這個模型。在這種情況下，我們已經得到了

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

細菌病菌，記得它是一種病毒，感染細菌。 但這不是什麼細菌病菌。但這不是什麼

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

問題是關於。他們要你說這對遺傳變異有什麼影響？

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

在細菌中。現在記住，細菌不'性。他們不做減數分裂和生產

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

精子和卵子。那麼我們怎麼能在其中獲得變異呢？好吧，讓我們看看是怎麼回事。

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

所以，細菌被注入了細菌病毒的DNA。這基本上就是編程

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

細菌，以製造更多的病毒。除了有'的一件事就在這裡。在

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

這一點，而不是這種病毒被包裝成病毒DNA，'的細菌創造的。

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

它的包裝與細菌DNA。是以，隨著這些病毒傳播出去， 這一個病毒是：

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

將細菌的DNA注入另一個細菌中。所以它將DNA從一個細菌中轉移到另一個細菌中。

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

到另一個。那會給新的細菌帶來什麼？它會給它帶來變化。

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

所以我又把我的知識應用到一個模型或視覺表現上。然後

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

最後一個是我們需要能夠重新表達模型和表示。所以在這個

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

一個我們正在尋找信號轉導。所以你可以看到，在這裡，我們已經得到了一個

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

胰島素受體，然後我們''ve得到了glut或我們''ve得到了一個葡萄糖運輸。所以，什麼'的

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

問題的提出？信號轉導關鍵要素的變化如何改變細胞反應？

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

所以現在他們又要求你運用你所掌握的知識。在這種情況下。

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

胰島素為什麼重要？胰島素要與胰島素受體對接，但什麼？

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

它'的真正要打開的是將這些葡萄糖運輸。換句話說

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

它'要打開這個門，所以葡萄糖可以進入細胞。所以，什麼是一些

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

的問題，我們可以問從？嗯，讓我們說有'沒有胰島素。如果有'沒有胰島素

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

在這裡，將沒有信號傳導，它不會打開，它不會。

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

將允許葡萄糖進來。所以，如果你'是I型糖尿病患者，如果你不'有胰島素。

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

他們你'的運氣。但讓'說你'是一個II型糖尿病患者。哪兒的問題去

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

要在那裡？現在我們的胰島素受體本身就有問題。我們正在創造

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

胰島素，但它'沒有與胰島素受體正確對接。什麼'的，要

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

做？我們仍然沒有'信號轉導。我們仍然沒有一個葡萄糖運輸的開口。

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

了。所以這些問題都是你在AP生物考試中可能發現的問題。

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

春天。換句話說，他們'要求你使用模型，創造模型。但模型是

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

整齊。它們讓我們能夠理解一個心理模型。而很多時候，它得到視覺和

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

它變得更容易理解。而且他們'被科學家們使用。什麼是最著名的

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

所有的模型？這個模型是由詹姆斯-沃森和弗朗西斯-克里克開發的，就在這裡。

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

他們正在和麥卡蒂握手，他是想通了的科學家之一。

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

那是DNA，實際上是做 細菌內部的轉變。但他們是

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

能夠建立一個模型。他們能夠建立一個模型，因為他們知道DNA是由什麼組成的。

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

組成的。他們知道它是由磷酸鹽，糖和這些含氮鹼組成的。他們

knew the ratio of the bases. But until they could physically build it, they couldn't visualize

知道基地的比例。但是，在他們能夠實際建造之前，他們無法直觀地看到

it. And so models and visual representations are incredibly important. In AP Biology it

它。所以模型和視覺表達是非常重要的。在AP生物課上

will help you do better on the test and I hope that was helpful.

會幫助你在考試中做得更好，希望對你有所幫助。