Lesson video

Hello and welcome to today's lesson from the Unit: Heredity and DNA.

And the title of today's lesson is Genetic Material and DNA.

So what we're gonna be looking at today is how DNA is stored within cells? What its job is and what it's made up of? My name Mrs. Barnard, and I'm going to be taking you through today's lesson.

And by the end of today's lesson, you should be able to describe what genetic material is and where it is stored in animals, plants, and microorganisms. And we've got some keywords in today's lesson.

And our keywords for today are cytoplasm, nucleus, bacteria, DNA, and genetic code.

And I'm gonna put the slide up of the definitions.

So you can pause the slide here so that you can write these down.

Okay, and then that means that you'll be able to refer to them later in the lesson if you need to.

Okay, our lesson today is in three parts.

We've got storage of genetic material, role of genetic material, and DNA.

So let's get started with our first part of today's lesson, which is storage of genetic material.

Okay, to start with, I'm going to take you back to a unit of work that you will have already completed, which is on cells.

So all living organisms are made up of cells.

They are the living building blocks and all things, all living organisms alive on earth are made of these cells.

And all animal plant and fungi cells contain structures which include cell membrane, cytoplasm, and nucleus.

So you might recall these labels.

We've got the cytoplasm, remember, which is the jelly-like substance inside the cell where the chemical reactions take place.

We've got a cell membrane, so that's around the outside of the cell, and that controls what enters and leaves the cell.

And then we've got the nucleus.

And the nucleus is where the genetic material is stored.

So within an animal cell and a plant cell and a fungi cell, the genetic material is stored in the nucleus.

And you can see there's a nucleus in each of those examples.

It's a separate structure, so it's usually quite easy to identify.

And we can see a nucleus in lots of cells when we look down a microscope.

Bacteria though are unicellular microorganisms. They don't store their DNA in a nucleus.

They store it in the cytoplasm in a loop.

There it is the genetic material in its cytoplasm.

So time for a quick check.

Which cells store genetic material in the nucleus.

So pause the video while you decide which are the correct answers.

Okay, let's see how you did.

So we have plant cells.

They store their genetic material in nucleus.

We have animal cells.

They also store it in a nucleus.

And finally fungi cells store it in a nucleus.

However, bacterial cells do not.

They store it in a loop in the cytoplasm.

So time for a practise slide now.

So Izzy, Sam, and Alex are our pupils, and they're discussing how genetic material is stored in cells.

So they've got quite a few different ideas.

So Izzy says that "Bacteria and fungi are not living and so do not need genetic material.

Animal and plant cells, though, store their genetic material in a nucleus." And Sam says, "All cells store genetic material in their nucleus to keep it safe." And Alex says, "Bacteria cells do not have a nucleus as they do not have genetic material.

They are only one cell, and so have no features." So you're gonna need to take your time to read through each of those ideas from those pupils.

All of them, however, are incorrect.

I would like you to take each pupil's statement and write it out, but with their errors corrected.

So you are taking each statement and just improving that statement by correcting the errors.

So you're gonna need a little bit of time to do this.

So if you want to pause the video and then we'll come back and see how you got on.

Okay, shall we see how we got on with that then? So take each pupil's statement and write it out with corrections.

So we've got Izzy.

So bacteria and fungi are living, she said they weren't.

And so they do need genetic material.

Animal, plant, and fungi cells store their genetic material in the nucleus.

So with those, the corrections that you made for Izzy, if you did, then that's really good.

Well done.

So let's have a look at Sam now.

So for Sam, we're gonna correct him by saying animal plant and fungi cells store their genetic material in their nucleus to keep it safe.

Bacteria do not, 'cause remember Sam said all of the cells store DNA genetic material in their nucleus.

And then let's have a look about Alex.

So Alex, bacteria cells do not have a nucleus, but they do have genetic material.

So he said they didn't have genetic material, but they do.

And they store their genetic material in the cytoplasm.

So if you made those corrections the same as mine, then well done.

So it's time for us to move on to the second part of our lesson today, which is the role of genetic material.

So genetic material provides the instructions used to build inherited features and to control life processes in all living organisms. So we've talked about how all cells contain genetic material either in the nucleus or as in the bacteria loose in the cytoplasm because all of those cells will need instructions and they need them for their features, but also life processes that all living things carry out.

And during reproduction, the genetic material is passed on from the parent to the offspring.

So I've got an example here with bacteria.

So we've got the bacteria, which is the parent, one in this case, and it's got its genetic material there in the cytoplasm, and it makes a copy of its genetic material, and then it passes it on to its offspring.

So you can see that the genetic material is passed from one generation to the next.

It's slightly different in this example, because most examples we've looked at in the past is two parents passing on their genetic material to their offspring.

The process of passing on genetic material is still the same.

It's passed on from a parent to an offspring.

So many of the features that are inherited can be seen when the offspring is produced.

So you can see in this puppy here looks quite similar to its parent there.

So you can see the inherited features that have been passed on quite clearly.

However, in this example with the frog, you can see it's offspring surrounding it there in the frogspawn.

That frogspawn doesn't look much like that frog right now, but later on in the lifecycle of that frogspawn, so once they become tadpole and then froglets and then frogs, they definitely will resemble those frogs.

And you'll be able to see the inherited features that have been passed on.

And those features that you can't see, those are to do with controlling processes like growth or germination in plants are passed on from parent to offspring, which allow, for example, these plants to grow.

So time for a true or false now.

So features that offspring share with their parents are passed on by instruction in their genetic material.

So first of all, do you think this is true or false? And then once you've decided that you need to decide which of these statements would justify your answer.

So would it be that all features a living organism has are passed on from their parents, or would it be all inherited features and processes a living organism has are passed on from their parents? So pause the video while you decide and then we'll come back and have a look at your answer.

Okay, let's see how you got on.

So features that offspring share with their parents are passed on by instruction in the genetic material.

This is true.

And how are we gonna justify the answer? we're gonna justify it with because all inherited features and processes a living organism has are passed on from its parents.

The statement above said, all features are passed on, but we know that some features are due to environment or lifestyle.

So those are not passed on.

So another quick check here.

So for each of these statements, I want you to decide whether it is correct or incorrect.

And then once you decided whether it's incorrect or correct, I want you to decide how sure you are about that.

So for example, bacteria have genetic material.

Do you think that that is correct or incorrect? And once you've decided, are you sure you are right or do you think it's right or do you think it's wrong or you're sure it's wrong? Okay, again, pause the video while you go through each of those statements to decide.

Okay, let's have a look at your answers then.

So bacteria have genetic material.

It is correct.

Okay, so whether you are positive or not as positive, it is correct.

Okay.

The next one.

Genetic material provides instructions for features and processes.

That is also correct.

And then genetic material can only be stored in a nucleus.

That's incorrect because we know that bacteria can store their genetic material in the cytoplasm.

And finally, genetic material can be passed from a parent bacteria to its offspring.

Okay, that is also correct because bacteria are living organisms and they too pass on their genetic material from one generation to the next, from parent to offspring.

Okay, time for a little bit of a longer answer now.

So we've got a couple of answers to do.

So in this picture, we've got a dog and it's puppy.

And I would like you to explain the role.

So the job of the genetic material in the similarities there are between this dog and its puppies.

So what role does the genetic material play? And then again, I'd like you to do this for a plant, but I would like you to explain the role of the genetic material in producing a new plant.

Okay.

So this is gonna take you a little bit of time to answer.

So pause the video and we'll come back and we'll look at your answers after.

Okay, let's see how you got on then.

Explain the role of genetic material in the similarities between the dog and the puppy.

So the genetic material is passed from the dog to the puppy in a reproduction.

And the genetic material provides instructions for building inherited features and for controlling life processes.

So what we're saying is that we know that genetic material is passed on and we know it's in reproduction, which is an important key word.

And we're saying that we know that this genetic material provides instructions and it allows inherited features and life processes to be controlled.

And finally, we're gonna say that the features of the dog in its puppy are similar because the puppy received half of its genetic material from the dog.

Okay.

So if you've got any of those statements, then well done.

And then let's move on to the second one.

So to explain the role of genetic material in producing new plants.

So first of all, we've got the genetic material is passed from the plant into a seed, and then we've got a new plant grows from that seed.

And then the genetic material provides instructions for the features and controls the life processes of the new plant.

So similar to the statement above.

So we say genetic materials pass from one generation to the next, and that happens during reproduction, and then it controls the features and life processes of the offspring.

So if you've got any of those correct, then well done.

Okay.

And then we're going to move on to the next part of our lesson.

So the genetic material of all organisms is made of a chemical substance.

Now that chemical substance is called DNA.

Now that's something you might have heard of before.

It's often in TV shows or films or computer games.

So DNA is what our genetic material is made up of.

So here's an example of a cell.

We've got an animal cell here, and we can see that it's nucleus is labelled.

And if we could look inside that nucleus, we would be able to see that all wound up and packaged inside that nucleus is the DNA.

And we can see that that DNA does look like a chemical molecule.

It's made up of smaller chemical groups to form this very, very long molecule.

So it is a long chain of these smaller chemical groups, these smaller molecules that are joined together.

And the chain is built from four different types of smaller chemical groups, molecules, and scientists call them A, T, C, and G.

Now, you'll come to learn lots more about those later on in the unit, but also later on in biology in future years.

They're very, very important because they form the genetic code.

So you can see those letters there, A, T, C, and G.

So that is our genetic code.

And that genetic code provides instructions and it gives the instructions for all inherited features, including those that control life processes.

And this is in all living organisms. So all living organisms on earth use DNA as the basis for their genetic code.

Now, that's a really good piece of evidence for evolution that we all originally came from the same microorganism and we've evolved through millions of years into all of the variation that we see on earth today.

But we all use DNA as the genetic code that gives the instruction for our features and our life processes.

An analogy can help us to understand this.

Often, ideas, insights are quite complicated.

So sometimes it's good to compare them to something that's every day.

It helps us make a bit more sense of it.

And we call these an analogy, and analogies are often used in science to model things.

Okay, so let's do an analogy for this.

So to start with a recipe book, hopefully everybody's come across a recipe book before.

Okay, I know lots of recipes are online now, but you used to be able to get them in recipe books.

And a recipe book is made of paper.

And that paper is like the genetic material of the DNA.

So genetic material is made of DNA and a recipe book is made of paper.

And inside that recipe book, if we opened it, we would be able to see that there are instructions and they're written using letters A to Z.

So that is like our genetic code.

So our genetic materials stores instructions, but it's written with chemical molecules, A, T, C, and G.

Now, if we put together the instructions that's in our recipe book, we can make something, so for example, a cake.

If we use the genetic code inside our DNA, we can use it as instructions to make a living organism.

So hopefully that analogy has made it a little bit clearer what the difference between those different key words is and how we get from this code to all of the features that make up a living organism.

So it's time for a quick check now.

So true or false? DNA and genetic code are the same thing.

And once you've decided whether you think that statement is true or false, I want you to decide underneath which of these statements would justify your answer? Is it that DNA is a chemical substance that stores the genetic code? Or is it DNA is just another name for the genetic code? So pause the video while you decide.

Okay, this statement, DNA and the genetic code are the same thing, is false.

They're not the same thing.

It's like the difference between the recipe book that's made of paper and the recipe that's made of letters.

And the correct justification is that DNA is a chemical substance and stores the genetic code.

Okay, so we've got a little practise test for you to do here.

Might take you a little bit of time, but they're two puppies and each have a different genetic code.

So we've got the code here on the top.

So we've got puppy number one, and it's got yellow, purple, blue or brown.

So that's its code.

And we've got puppy number two, and it's got pink, red, orange, and green.

So that's its code.

So what I want you to do is to use the code using the tables below, so the colour code, to find out which features those puppies have inherited in their genetic code, what instructions have they inherited.

And then I want you to draw me a picture of two puppies with the features that you found in their genetic code.

Now, don't worry how good your pictures are.

It's not about being a great artist, okay? We haven't, not got very long to do it.

Maybe only a few minutes, all right, to do your drawing.

So just do the best that you can, but just make sure that those key features are clear and that they're labelled in your diagram.

So pause the video while you do this.

Okay, hopefully you've got two pictures of puppies now with all the features labelled on them.

So let's have a look.

So we've got the code, remember for puppy number one and the code for puppy number two.

So let's look at puppy number one, first.

There, it's now I can't admit that I drew this, okay, but I did colour it in.

Okay, and here's our puppy number one, and you can see that he has got pointy ears and he has got ginger fur and he has got curly fur and he's got brown eyes.

Okay? So that's what you should have on your drawing of puppy number one.

So have a look at puppy number two.

So puppy number two should have floppy ears.

It should have black fur.

The fur should be straight, and he should have blue eyes.

So you have decoded the genetic instructions in order to show the features that have been passed on from the parents to the offspring.

So now we come to the end of our lesson.

So let's go through our summary.

All plant, animal and fungi cells are made of parts including a cell membrane, a cytoplasm, and a nucleus.

And the nucleus stores the genetic material of the organism.

Bacteria are unicellular organisms and have no nucleus.

Their genetic material is stored in the cell cytoplasm.

Genetic material is made from a chemical substance called DNA.

DNA is built from four different molecules called A, T, C and G, which form a genetic code used as the instructions to build inherited features and control life processes in living organisms. Well done with your work in today's lesson.