Lesson video

Hi, everybody it's Miss Simkin here, ready to teach your science lesson today.

It's nice to see you all back for our next lesson, in our history of science unit.

I hope that you are having a good day and that you've been well since the last time we had a lesson.

Let us get started on today's lesson.

So our lesson question today is how has the discovery of DNA changed science? But don't worry if you don't know what DNA is, I'm going to teach you what it is.

In today's lesson, we're going to start with our star words.

Then we're going to learn what DNA is.

Then we're going to learn the story of the discovery of DNA.

Then we're going to learn about the scientific developments or some of the scientific developments that have come out of its discovery.

And then at the end of the lesson, you'll have a chance to take your end of lesson quiz and see how much you have remembered.

For your lesson today.

You're going to need these things.

A piece of paper, a pencil, a coloured pencil.

You might want more than one colouring pencil today, because we're going to be doing some drawing and also a ruler.

If you don't have what you need, could you pause the video and go and get it for me now, please.

Great, okay let's start with our star words.

I'm going to say them.

And then you're going to say them.

DNA.

Inherited disease.

Treatment.

Cure.

Cell.

Good job, now DNA I'll explain in a moment, but I'll tell you what the other star words mean now.

So an inherited disease is a disease that you are born with.

So there are some diseases that we're not born with.

For example, you might catch the flu in the winter, that's not a disease you're born with.

You catch it at a certain point in your life.

And then you get better, you don't have that disease anymore.

But some diseases are diseases that people can be born with.

So an example is cystic fibrosis, is a disease that affects your lungs and you're either born with it or you're not.

Okay.

Treatment is medical care to make you better.

So if we go back to our flu example, treatment for the flu might be something like hot drinks or paracetamol or decongestion.

Okay, things you might take when you're poorly, when you've got the flu.

A cure is when somebody is relieved of all the symptoms of the disease.

So while you have a disease, you have treatment.

And then when that disease is completely gone, that's it cured.

Okay, so some medicines can cure a disease.

They can get rid of it completely.

Some medicines just help to treat it, to make it a bit better.

And a cell is the smallest unit of any organism.

That means all organisms, all living things, plants, animals are made up of cells.

But they're so small that you can't see them.

Okay, so my skin is made up of lots and lots of skin cells, but they're so tiny, I can't see the individual cells, at least not unless I had a powerful microscope.

Let's talk about what DNA is.

Now, this is some quite tricky science that we're going to do today, but I think you are ready for it.

So every living thing is made up of cells.

They're too small to see with the naked eye and inside every single cell, there is DNA.

So you see the picture, the circle is the cell, and then the kind of squiggly thing inside it, that's the DNA.

Point to the DNA on the screen.

Great.

DNA is the material that carries all the information about how a living thing will look or function.

So for example, DNA carries the information about the eye colour, your hair colour, or how your voice sounds.

Okay, so my DNA carries information that says blue eyes.

Your DNA might carry information, that says something different.

You can think of DNA like a set of instructions.

It's instructions that tells the cell, what to look like and what to do.

What can you think of DNA as? A set of instructions.

Great.

Okay, pencil and paper ready? Can you please fill in the gaps of this explanation.

Inside every cell there is mm.

DNA is the material that carries that the mm that's a living organism needs.

Pause the video and break this explanation down now, please.

Great, good job.

Let's check our answers.

So inside every cell there is DNA.

DNA is the material that carries the instructions that a living organism needs.

You could also have written information there.

If you wrote information, you can give yourself a tick.

If you need some time to correct your answer, pause the video to do that for me now.

Otherwise let's continue.

So DNA is made up of two long strands.

One strand goes like this and the second strand that goes like that.

And we call that structure a double helix.

Double because there's two hands.

And then that helix is referring to the shape, the like the wiggle.

Okay, so this we call the structure of DNA the double helix structure.

Take a mental image in your brain, because I'm going to ask you to draw this in a second.

Can you please draw an example of what DNA looks like? And then add a label that shows the double helix structure.

So label it double helix structure.

Pause the video and do that for me now, please.

Great.

Did it look this? Well done.

In the next part of the lesson, we are going to talk about the story of how DNA was discovered.

Like most discovery stories and science it's not simple.

It was the work of lots of people, that led to the full discovery and understanding of DNA.

We're just going to look at four different people's contribution to that.

Okay, there are always scientists and science that we don't have time to talk about.

And we've seen throughout this unit that the work of so many people leads to kind of the end goal or the end discovery where we are today.

But we're going to look at four people's work today.

So the first person is this, this is Friedrich Miescher.

And he was born in 1869.

And he was the first person to identify that there was a part of the cell that was different to the rest of it.

So he managed to isolate DNA.

He didn't call it DNA at the time.

He managed to have a cell and take DNA out of it.

So you could see that they were two separate things.

There was the cell and then there was something inside it that he could isolate, that he could separate.

He actually called it nuclein at the time, but we now know that it was DNA.

But that was an important step because we didn't know that DNA existed until he was able to do that.

He didn't understand what it was at that time, but he was able to isolate it.

Okay.

Can you show me an action to describe what Frederick Miescher was able to do? I'm doing one for you now.

He's isolating, he's taking it out of the cell.

Great, good job.

Okay, the next person in our story comes along in 1951.

So almost a hundred years later.

And this scientist was called Rosalind Franklin.

And she was the first person to take an X-ray photograph of DNA.

So before it had been isolated, but she was the first person to take a detailed photograph so we can actually see the structure, that double helix structure of the DNA.

So that was a really important step.

Because understanding DNA structure was what enabled us to then understand what it's for and how it works.

Then we had two scientists, called Watson and Crick only a couple of years later.

And they published a paper on DNA structure and all about the model of DNA, how they thought it worked based on its structure.

This is a really, really famous paper.

And it was a huge discovery.

But it wouldn't have happened without the work of Rosalind Franklin.

And in fact, Watson and Crick saw Rosalind Franklin's photo, her x-ray photograph of DNA.

She didn't know that she'd seen it.

She hadn't published it, but another science had shown it to them without her knowledge.

And seeing that photo was what inspired them and kind of stimulated their ideas about DNA and DNA structure.

Without that inspiration, where you could clearly see the helix shape, they wouldn't have been able to publish their paper on the helix shape.

And actually, this is one of those stories in science, which is a little bit sad, because Rosalind Franklin didn't get any credit for her work at that time.

Watson and Crick didn't thank her for a photograph.

They didn't mention her in her paper.

They didn't give her any of the credit that she deserved because she was a woman working in science at that time.

And it wasn't until after Rosalind Franklin died, that Crick then came forward and said that her contribution had been really important.

So it took him a very long time to do the right thing.

So that's the third step in our story of discovery.

So first it was isolated, then it was photographed.

And then those kinds of bits of information were put together.

And Watson and Crick published their famous paper on DNA in this discovery of DNA.

So often when people ask who discovered DNA, the answer, the easy answer is Watson and Crick.

But actually we know that it was the work of other scientists that enabled that discovery as well.

We are going to now create a comic strip that with three boxes that shows the three parts of this story.

Okay.

I put a word back on the side to help you.

So for each part of your comic strip, I'd like a picture and a sentence.

a picture and a sentence, a picture and a sentence.

Okay and you can use the word back on the side of the screen to help you.

Can you please pause the video and enjoy your comic strip for me now, please.

Great, fantastic.

Well, I hope you enjoyed doing that.

In the next part of the lesson, we're going to look at the scientific and the medical developments that were able to occur once we discovered and understood DNA.

Now this was a huge moment in science and it's had lots of implications and led to lots of developments, that we're not going to have time to look up today.

We could honestly be here all day looking at DNA and science.

But we're just going to look at two key ones today.

So the first is to do with inherited diseases.

We spoke about these at the beginning of the lesson, in our star words.

Can you remember what an inherited diseases is? Tell your screen.

Okay, it's a disease that you're born with.

Now inherited diseases come from a mistake or a mutation we call it in the instructions on our DNA.

So we are born with them and it's our DNA that's to do with inherited diseases.

So once we understood what DNA was and how it worked, it led scientists and doctors to have a much better understanding of how inherited diseases work.

And once they were able to understand inherited diseases better.

It meant that there could be more treatments and more cures for inherited diseases.

Okay, so that greater understanding led to more treatments and more cures.

What did greater understanding lead to? More treatments and more cures.

Great, good job.

The next scientific development is called DNA fingerprinting.

What's it called? So, DNA fingerprinting is important for lots of reasons, but one of them is when somebody commits a crime.

So when somebody commits a crime like robbing a bank, for example.

They will often leave really small parts of themselves behind.

They might leave a piece of hair behind or an eyelash might fall out, but sometimes it could be even smaller.

Something that you wouldn't even be able to see.

Like a drop of saliva that might've come out while they were speaking or just a drop of sweat.

Now, even in something as small as one drop of sweat, you can find DNA.

And that DNA can then be studied and it can be matched to the suspect of the crime.

This works because everybody's DNA is unique.

So my DNA is completely different to your DNA.

You would be able to tell us apart by looking at our DNA, it's like a fingerprint.

Did you know that everybody's fingerprint in the world is different.

Well your DNA is the same as well.

That's why we call it DNA fingerprinting.

So they can take a sample of DNA from the suspect, the person who they think might have done it.

And they can take that sample of DNA, that was left at the crime scene and if they have a match, then they know that their suspect was there and that their suspect that might have committed the crime.

Okay, so it's really important scientific development that has led to much better crime scene analysis and means that we're able to catch more criminals.

Okay, can you please answer this question? Describe two scientific developments that have occurred due to the discovery of DNA.

Pause the video and answer this question for me now, please.

Great, good job.

So you might have written something like this.

Don't worry if you've got different wording to me, I've written this.

The discovery of DNA has led to DNA fingerprinting, which can help to find people who committed crimes.

And it has also led to a greater understanding of inherited diseases and more treatments and more cure cures for these.

So the key things to have here are DNA fingerprinting and understanding inherited diseases.

So can you just check your answer and give yourself a tick next to DNA fingerprinting where you've written that and a tick next to understanding inherited diseases.

If you've missed out either of those things then pause the video, use my answer on the screen and correct your answer for me now.

Great, you could also see how in my answer I've explained DNA fingerprinting and understanding inherited disease.

I haven't just said the discovery of DNA has led to DNA fingerprinting and understanding genetic inherited diseases.

I've said the discovery of DNA has led to DNA fingerprinting, which can help people to find committed crime.

So I've expanded, I've explained both of those things.

If you didn't do this, that's okay.

But now is the chance to make your answer even better.

So can you use my answer on screen to help you edit your answer and add in an explanation, if you need to.

Pause the video to do that for me now, please.

Great, good job.

That brings us to the end of the lesson.

I hope you enjoyed learning about some really complicated science today.

The fact that you now know about DNA, means you're a bit of a super scientist.

Great job today.

Well done for all of your hard work.

Just before you go, don't forget to do your end of lesson quiz.

I hope you have a fantastic rest of your day.

Thank you for working so hard today.

And hopefully I will see you back here soon for another science lesson.

Bye everybody.