2024年6月21日 星期五
2024年6月18日 星期二
《Writing to Learn》的翻譯和句型分析進度
《Writing to Learn》
- 本書的作者的序言第1-6段，翻譯和句型分析已完成。第1~33句。
- 本書的作者的序言第7-8段，翻譯和句型分析已完成。第34~46句。
- 本書的作者的序言第9-10段，翻譯和句型分析已完成。第47~56句。
- Chapter 1 Hermes and the Periodic Table，第1-5段翻譯和句型分析已完成。第57~91句。
- Chapter 1 Hermes and the Periodic Table，第6-8段翻譯和句型分析已完成。第92~110句。
- Chapter 1 Hermes and the Periodic Table，第9-10段翻譯和句型分析已完成。第111~123句。
- Chapter 1 Hermes and the Periodic Table，第11-12段翻譯和句型分析已完成。第124~135句。
- Chapter 1 Hermes and the Periodic Table，第13-14段翻譯和句型分析已完成。第136~146句。
- Chapter 1 Hermes and the Periodic Table，第15-16段翻譯和句型分析已完成。第147~158句。
2024年6月14日 星期五
Comparing animal and plant cells
Comparing animal and plant cells
So let's play a game of Spot the Difference.
Now, if you were asked to spot the difference between these two pictures, you'd probably laugh and say, "That's too easy."
Because it's obvious that this picture of a lion on the left is nowhere close to looking like the picture of a green fern plant on the right.
What's more, a lion and a fern not only look completely different, they also function differently.
But what if I told you that if we zoomed in really close and compared the lion's cells with the fern's cells, they'd actually share many similarities?
An animal cell and a plant cell have several common features as well as a few key differences.
In this video, we're going to spot the similarities and the differences between the two types of cells, and talk about their functions inside the cells.
So, first off, let's take a look at some cell models.
Here on the left is an animal cell, and on the right is a plant cell.
First, let's try and identify the things that both animal and plant cells share in common.
If you recall, both animal and plant cells have a cell membrane, which acts like a gate to control what enters and leaves the cell.
Animal cells and plant cells also have this jelly-like substance called the cytosol, which contains organelles or small compartments with specific functions inside the cell.
Animal and plant cells share several common organelles, two of which include the nucleus and the mitochondria.
The nucleus within each cell type serves as an information database to store the cell's genes, while the mitochondria act as factories to break down sugars and release energy that the cells can use.
So now that we've identified some features found in both kinds of cells, let's look closer to spot the fundamental differences between animal and plant cells.
As you can see in this diagram, plant cells have an additional layer of material that surrounds the cell membrane.
This is called a cell wall, which makes the plant cell more structured and stiff.
Think of a celery stalk compared to a raw piece of chicken or fish.
The animal muscle tissue is floppywhile the celery stalk is firm.
That's cell walls in action.
Also, plant cells have these special organelles called chloroplasts, which are what give plants, like the fern we saw, their green color.
Chloroplasts are the site of photosynthesis, which is how plants make their own food in the form of sugars.
If the word sugar rings a bell, you're on the right track because I mentioned earlier that mitochondria are responsible for breaking down sugars.
In plant cells, chloroplasts and mitochondria are like good buddies that help each other and work together.
Chloroplasts make sugars through photosynthesis and mitochondria convert the sugars into energy that, ultimately, the plant can use.
Both cell walls and chloroplasts are found in plant cells but not animal cells, such as the ones in you and me.
And luckily for you and me, this means we aren't green.
In summary, we just identified several similarities and differences in our comparison of animal and plant cells.
While both cell types have a cell membrane, cytosol, a nucleus, and mitochondria, plant cells have a cell wall that makes them stiff and rigid, think about celery stalks, and they have chloroplasts, which makes sugars and give plants their green color.
All of these are just a handful of the similarities and differences between plant and animal cells.
As you go forward in your biology journey, you'll probably learn about a lot more.
But the differences that we've covered are a big part of what makes plant and animal cells so distinct and unique from each other.
These differences are why we don't see green lions that photosynthesize using chloroplasts or floppy raw veggies with cell membranes but no cell walls.
Now I hope that you have a clear understanding of the different cell parts in both animal and plant cells, and that spotting the differences between the two will be easy breezy.
Now, if you were asked to spot the difference between these two pictures, you'd probably laugh and say, "That's too easy."
Because it's obvious that this picture of a lion on the left is nowhere close to looking like the picture of a green fern plant on the right.
What's more, a lion and a fern not only look completely different, they also function differently.
But what if I told you that if we zoomed in really close and compared the lion's cells with the fern's cells, they'd actually share many similarities?
An animal cell and a plant cell have several common features as well as a few key differences.
In this video, we're going to spot the similarities and the differences between the two types of cells, and talk about their functions inside the cells.
So, first off, let's take a look at some cell models.
Here on the left is an animal cell, and on the right is a plant cell.
First, let's try and identify the things that both animal and plant cells share in common.
If you recall, both animal and plant cells have a cell membrane, which acts like a gate to control what enters and leaves the cell.
Animal cells and plant cells also have this jelly-like substance called the cytosol, which contains organelles or small compartments with specific functions inside the cell.
Animal and plant cells share several common organelles, two of which include the nucleus and the mitochondria.
The nucleus within each cell type serves as an information database to store the cell's genes, while the mitochondria act as factories to break down sugars and release energy that the cells can use.
So now that we've identified some features found in both kinds of cells, let's look closer to spot the fundamental differences between animal and plant cells.
As you can see in this diagram, plant cells have an additional layer of material that surrounds the cell membrane.
This is called a cell wall, which makes the plant cell more structured and stiff.
Think of a celery stalk compared to a raw piece of chicken or fish.
The animal muscle tissue is floppywhile the celery stalk is firm.
That's cell walls in action.
Also, plant cells have these special organelles called chloroplasts, which are what give plants, like the fern we saw, their green color.
Chloroplasts are the site of photosynthesis, which is how plants make their own food in the form of sugars.
If the word sugar rings a bell, you're on the right track because I mentioned earlier that mitochondria are responsible for breaking down sugars.
In plant cells, chloroplasts and mitochondria are like good buddies that help each other and work together.
Chloroplasts make sugars through photosynthesis and mitochondria convert the sugars into energy that, ultimately, the plant can use.
Both cell walls and chloroplasts are found in plant cells but not animal cells, such as the ones in you and me.
And luckily for you and me, this means we aren't green.
In summary, we just identified several similarities and differences in our comparison of animal and plant cells.
While both cell types have a cell membrane, cytosol, a nucleus, and mitochondria, plant cells have a cell wall that makes them stiff and rigid, think about celery stalks, and they have chloroplasts, which makes sugars and give plants their green color.
All of these are just a handful of the similarities and differences between plant and animal cells.
As you go forward in your biology journey, you'll probably learn about a lot more.
But the differences that we've covered are a big part of what makes plant and animal cells so distinct and unique from each other.
These differences are why we don't see green lions that photosynthesize using chloroplasts or floppy raw veggies with cell membranes but no cell walls.
Now I hope that you have a clear understanding of the different cell parts in both animal and plant cells, and that spotting the differences between the two will be easy breezy.
Cell parts and their functions
Cell parts and their functions
So let's imagine this scenario.
It's cold outside and we want to make a nice hot bowl of chicken noodle soup.
Well, we'd probably need to get the ingredients first.
We need some chicken bones to give the broth that distinct chicken flavor, some noodles to add that starchy component, carrots and onions to give some sweetness and color.
And of course, salt and pepper to provide seasoning.
All of these ingredients would come together to make our chicken noodle soup the comfort food that so many people love, but this video is supposed to be about cells.
You know, those tiny things that make up all living things on earth.
So why am I telling you about chicken soup?
Well, just like how each ingredient in chicken soup adds something unique to the soup's overall flavor
and texture, a cell's different parts add something unique and necessary for the overall functioning of the cell.
So, let's take a look at some of the structures inside a cell and see how their functions come together
to allow cells to carry out all the processes of life.
So let's explore the parts of a cell starting with the cell's surface.
Cells are separated from their outside environment by a cell membrane.
You can think of the cell membrane like a fortress gate, because it regulates what comes into and out of the cell, and contained within the cell is a jelly-like substance that fills out the cell and contains its internal parts, this jelly and all the structures within it make up the cell cytoplasm.
Unlike chicken soup, the cell parts in the cytoplasm are not just floating around.
Instead, they're organized and held in place by an internal structural network.
Some of the parts contained within the cytoplasm are called organelles.
So what exactly are organelles?
Well, organelles are small compartments in the cell that have different structures and functions.
The word organelle basically means, mini organ.
And just like how our bodies are made up of different organs that work together to help us stay alive,
cells contain different organelles that work together to get things done inside the cell.
For example, these jellybean-shaped organelles here are little energy-producing factories
called mitochondria.
So mitochondria use chemical reactions to break down sugar molecules in order to release energy that the cell can use for other tasks.
Another really amazing organelle is the nucleus.
You can think of the nucleus as the information database of the cell.
It contains DNA which includes the cell's genes.
Genes are special instructions that the cell uses to carry out its functions.
Moving over to a plant cell, we can see these green organelles called chloroplasts.
You might remember that plants carry out photosynthesis.
Well, chloroplasts are the organelle's responsible for this process.
Plants need food to live, just like animals do.
And chloroplasts use photosynthesis to produce sugars that plant cells use as food.
Plant cells also have a layer outside their cell membrane called the cell wall, which helps provide structure for the cell.
So as you can see, there are so many different parts that make up a single cell.
There are many, many organelles present in cells, way more than the handful I mentioned in this video.
And what's even more mind blowing is that these diagrams are only simplified versions of what cells actually look like.
And just to give you an idea, here's a picture of what a real cell looks like.
So when we're talking about cells and using these diagrams as references, keep in mind that these pictures are only simplified models of the real thing.
To wrap up this video on cell parts, let's revisit our delicious bowl of chicken noodle soup that I mentioned at the beginning.
Each ingredient that we added had a unique function that contributed to the soup's taste and texture.
And similarly, our cell's ingredients, its organelles and structures, each contribute a unique function
that helps the cell carry out all the tasks necessary for life.
So the next time you find yourself in front of a bowl of noodle soup, just imagine that you're eating one enormous cell.
Now, isn't that something to noodle on?
Introduction to Middle school biology
Introduction to Middle School Biology
Hi, everyone. Sal Kahn here.
And welcome to Middle School Biology.
I have Iman Howard here, who manages our STEM content.
Welcome, Iman, and why should folks care about middle school biology?
Biology is the study of life.
And so, in this course, it really answers why are things the way they are, why do you look the way they do, why do I look the way I do, and how every organism on Earth has a really special purpose and a special trait.
And based on these traits, it helps them interact with their environment.
We even talk about energy.
And energy can't be created and it can't be destroyed.
It actually cycles as matter through an ecosystem.
And it even has this really cool chemical reactions called photosynthesis, where plants use light energy from the sun and they make their own food, which is insane.
I think about organisms like the gorilla that are super-big and strong and they don't go and eat a cow.
They go and eat plants because that's like getting energy right from the source.
And then finally, we talk about evolution.
Based on our traits, how have we changed over time?
And how some of our natural traits were selected by the environment that create those changes or even how humans, we have something called artificial selection, which explains why your dog's so cute.
Whether it's 100 pounds or five pounds, we did that.
What do you think's cool about it, Sal?
Oh, well, you know, biology's trying to answer, I mean, to your point, the questions of life, which we still don't understand a lot about
but like what makes us us and to realize that we don't exist as human beings in isolation.
We're part of an ecosystem.
We're part of a story, a narrative that's been going on
for millions and billions of years.
The fact that we're made up of trillions of cells, each of them with DNA that can describe who we are, how did all of this complexity come about?
This is maybe the most mind-blowing topic that we're really at just the beginning of this journey.
So I think folks are gonna be really, really excited to or it's gonna be really interesting to see all of the things that they get to learn.
Well, let's dig in.
(enthusiastic chiming)
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