Lesson video

- Hello and welcome to today's Oak Academy science lesson.

My name is Mrs. Bowes and I'm really, really looking forward to this lesson with you.

So make sure that you're ready to learn.

Have in front of you a pen and some paper, and then we can get going.

The title of today's lesson is prokaryotic and eukaryotic cells, and the outcome is to identify prokaryotic and eukaryotic cells and describe the differences between them.

This is a science lesson and it comes under the topic, cell biology.

If you need to pause the video now to write down the title, please do, and then press play when you're ready to get going.

The keywords for today's lesson are bacteria.

A bacteria is a microorganism that is unicellular.

And unicellular is our second keyword.

A unicellular organism is made up of only one cell.

Today we'll be talking about one example of a unicellular organism, and just remember that that organism only consists of that one cell.

And then finally, a sub-cellular structure are smaller parts that make up a cell.

So if you have one cell, it's made up of smaller parts and they are called sub-cellular structures.

So the three keywords for today, bacteria, unicellular, and sub-cellular.

The outline of today's lesson will be as follows.

We are going to start by defining prokaryotic and eukaryotic cells.

Then secondly, we will identify examples of prokaryotic and eukaryotic cells.

And then to finish off the lesson, we will be comparing prokaryotic and eukaryotic cells.

But to begin with, let's look at the definitions.

So my first question to you is, do both of these cells that are on the slide now have a nucleus? We've got a bacteria and we've got an animal cell.

You have a think.

Do both of them have a nucleus? Now hopefully, what you are thinking is, "No, the bacteria cell doesn't have a nucleus" because you can see in that picture there it says no nucleus and there's just this big loop.

It looks like a piece of string in the middle of the bacteria.

That's actually the DNA, and it's just in one continuous loop in the cytoplasm.

So bacteria do not have a nucleus but the animal cell does have a nucleus, which you can can see in the picture, it's shaded a slightly darker colour, and the DNA would be contained within the nucleus in the animal cell.

We just can't see it in this picture.

So bacteria have no nucleus.

Animal cells do have a nucleus.

So here again we've got our bacteria cell and we have our animal cell.

Prokaryotic cells do not contain a membrane bound nucleus.

So a bacteria is an example of a prokaryotic cell.

Bacteria does not have a membrane bound nucleus, whereas a eukaryotic cell does contain a membrane bound nucleus.

So our animal cell, which does have a nucleus, and it's membrane bound, is classed as a eukaryotic cell.

And those are the definitions that you need to know.

A prokaryotic cell does not contain a membrane bound nucleus and a eukaryotic cell does contain a membrane bound nucleus.

Let's check how much we have understood so far.

So I'm gonna ask you a series of questions, give you a little bit of time to think.

There'll be some options of answers, and you need to pick which you think is the correct answer.

So the first question is, what is the definition of a eukaryotic cell? A, a cell with no membrane bound nucleus, B, a cell with no cell wall, or C, a cell with a membrane bound nucleus.

Remember, this is a eukaryotic cell.

You have a go now.

Hopefully we are all going for C.

Eukaryotic cells do have a membrane bound nucleus.

Our example was the animal cell.

Next question, what is the definition of a prokaryotic cell? A, a cell with no membrane bound nucleus, B, a cell with a membrane bound nucleus, or C, a cell with no DNA? You have a think and come up with your answer.

Hopefully here we've gone for A.

Prokaryotic cells have no membrane bound nucleus and our example was the bacteria cell.

I think now we should be ready to move on to our first task of the lesson.

So your job is to complete the label to say if each of those cells is eukaryotic or prokaryotic and then fill in the missing words using the words below.

Pause the video now, and press play when you're ready for me to go through the answers.

Okay, let's go through the answers.

So the first picture there is showing you our bacteria cell, and that is a prokaryotic cell because it does not have a membrane bound nucleus.

The DNA we can see there is just a big loop that's floating in the cytoplasm.

The next picture is our animal cell, and we can see that that does have a nucleus, which is membrane bound.

So therefore it is eukaryotic.

The second part of this, filling in the missing words, prokaryotic cells do not have a membrane bound nucleus but eukaryotic cells do have a membrane bound nucleus.

Absolutely amazing if you got that right.

Really, really well done.

We're ready now to move on to our second learning cycle.

So we are going to now identify some examples of prokaryotic and eukaryotic cells.

We have actually already talked about two already but we're gonna add a few more in.

So first thing, and we should know two of these, can you identify any of the cells that are on the slide right now? And now hopefully we already know the first one because we've spoken about that previously.

That is a bacteria cell.

Notice again that it hasn't got the membrane bound nucleus, it's just got the DNA loop within it.

We should know this one as well.

This is an animal cell which does have a membrane bound nucleus.

And then the next type of cell is a plant cell, specifically that is a palisade cell which you find in the leaves of plants.

And then the last one, little bit harder this, this is a fungi cell, but it is called a yeast cell which is a type of fungi.

And these are the four cells that we are going to be looking at today.

The only one of those four cells that is prokaryotic is the bacteria.

So bacteria are unicellular, they consist of only one cell, and they don't have a membrane bound nucleus.

So therefore they are prokaryotic.

And I think it's quite.

you can see looking at the pictures on this slide that it is the only cell that doesn't have that nucleus within it.

So the animal plant and fungi, they are all eukaryotic because they have a membrane bound nucleus.

So if we look in a little bit more detail about prokaryotic cells and our bacteria cell, bacteria are some of the simplest organisms that have ever existed.

They are usually unicellular organisms. Remember unicellular means that they consist of only one cell.

Bacteria are actually thought to be the first organisms that evolved on Earth.

And they're very, very simple, they're not very complex.

They're just made up of this one cell.

But they've also been around on Earth for a very, very long time.

And like we said before, bacteria are prokaryotic.

Question for you, how can we tell that bacteria are prokaryotic or why are bacteria prokaryotic? You just have a think now.

It's because they have no membrane bound nucleus.

If you knew that, really, really well done.

Fantastic.

So these are our three examples of eukaryotic cells we've spoken about, animal cells, plant cells and fungi.

And they are all eukaryotic because they contain membrane bound nucleus.

Their structures are usually more complex than prokaryotic cells, and they contain membrane bound sub-cellular structures.

So not just the membrane bound nucleus, there are other structures within eukaryotic cells that are membrane bound.

The mitochondria is one such example of a membrane bound organelle and they are found in animals, plants and in fungi.

And then also, plant cells contain a membrane bound organelle called a chloroplast, which is where photosynthesis occurs and that is unique to plant cells.

Animal, plants, and fungi cells also contain a sub-cellular structure called ribosomes, but bacteria and prokaryotic cells also contain ribosomes because they are not membrane bound.

Let's check our understanding, again.

So I'm gonna ask some questions.

You have your best go at answering them.

So the first question is, what type of cell is shown in this image? A, fungi, B, animal, or C, bacteria? Nice and easy this one.

Hopefully we got a bacteria.

And think now, is that prokaryotic or eukaryotic? It's prokaryotic, has no membrane bound nucleus.

Next question, what type of cell is shown in this image? A, fungi, B, animal, C, bacteria.

This one is B.

It is an animal cell.

Next question.

Which of the following is prokaryotic? A, animal, B, bacteria, or C, plant? This one, remember, prokaryotic means no membrane bound nucleus.

So this is B, bacteria.

Amazing if you remembered that.

Well done.

Is this cell here eukaryotic or prokaryotic? This is eukaryotic.

Remember, that's our animal cell.

Are plant cells prokaryotic or eukaryotic? Plant cells are eukaryotic because they have a membrane bound nucleus.

True or false? This picture shows a prokaryotic cell.

You need to decide whether that's true or false and then justify your answer.

So A, it has no membrane bound nucleus, or B, it has a membrane bound nucleus.

So you pick true or false and your justification.

What do we think? Let's remember what this cell is.

First of all, it's our plant cell.

Is it prokaryotic? False, it is not.

It's eukaryotic, justifying the answer, that is because it has a membrane bound nucleus, which is B.

So you should have had false and B.

Amazing if you got that.

Well done.

I think it's time for us now to apply our knowledge again to our second task.

And your job is to complete the table to give examples of prokaryotic and eukaryotic organisms. And those are gonna be examples that we have spoken about within the lesson.

There'll be nothing new in there, just the examples from this lesson.

So pause the video now, give it your best go, and then press play when you are ready for me to go through the answers.

Okay, let's get going.

So examples of eukaryotic organisms are animal cells, plant cells, and fungi, and we specifically spoke about yeast cells.

And then our one example of a prokaryotic cell is bacteria.

So mark your work absolutely brilliant if you managed to remember all of those.

Check your spellings, just make sure that you've got those right, and then we will continue.

So your next task is to name each of the cells in those diagrams. So pause the video now and try and answer that question, and press play when you are ready to begin.

Okay, let's go through the answers.

The first picture on the left there is our bacteria cell.

Remember, that is prokaryotic.

The second cell is the animal cell with a membrane bound nucleus, so eukaryotic.

The plant cell is also eukaryotic, and our fungi, and that specifically is a yeast cell, that is also eukaryotic.

Absolutely amazing if you managed to get all of those right.

That is brilliant, brilliant work.

Right, it's time for us now to move on to our final learning cycle.

We are going to be comparing prokaryotic and eukaryotic cells.

So now we know what they are, what they look like, some examples, we're gonna compare the two against each other.

The first thing that we are gonna compare are the membrane bound sub-cellular structures within prokaryotic and eukaryotic cells.

Prokaryotic cells do not contain membrane bound sub-cellular structures, and we've already spoken about this, but one of those structures is the nucleus.

So prokaryotic cells do not contain a membrane bound nucleus.

And instead, as you can see on the diagram, the DNA is free floating within the cytoplasm.

Prokaryotic cells do contain cytoplasm though, and they do contain ribosomes because ribosomes are not membrane bound sub-cellular structures.

So that bacteria cell has cytoplasm, it has ribosomes, and it's also got free floating DNA, but it has no membrane bound nucleus.

Now, eukaryotic cells contain membrane bound sub-cellular structures.

And some examples of these are the nucleus, the mitochondria, and the chloroplasts.

And every single one of the cells below has got a nucleus and mitochondria.

We can see that the nucleus is labelled in the yeast cell and the mitochondria is labelled in the animal cell, but also the plant cell has also got a nucleus and it has also got mitochondria.

But on the plant cell we have a chloroplast labelled, and chloroplasts are membrane bound organelles but they are unique to plant cells because that's where photosynthesis takes place.

So what you need to know from this slide is that prokaryotic cells do not contain membrane bound sub-cellular structures.

Eukaryotic cells do, and eukaryotic cells that we have spoken about today, yeast, animal, and plant cells, they all contain a nucleus and mitochondria, but plant cells also contain chloroplasts.

Now we're gonna talk about the DNA in prokaryotic and eukaryotic cells.

So prokaryotic cells contain no membrane bound nucleus and the DNA is free floating in the cytoplasm, whereas in eukaryotic cells, the DNA is contained within the membrane bound nucleus.

Now let's compare the sizes of the two organisms. Now, I'm gonna give you some generic sizes, and these are not the exact size of every single organism.

They are kind of roughly in general the sizes.

So prokaryotic cells in general are much smaller than eukaryotic cells, and their length is between one to five micrometres.

So that funny looking little U there, the funny looking U with the M is micrometres.

There are 1,000 micrometres in one millimetre, just to give you some context of the size.

So prokaryotic cells, their length is one to five micrometres.

They're much smaller than eukaryotic cells.

Eukaryotic cells are larger.

Their length is between five to 100 micrometres, so they are bigger.

So here you can see that bacteria cell is roughly one micrometre, whereas eukaryotic cells are five micrometres, or can be up to 100 micrometres.

So they are larger.

Now let's talk about how prokaryotic and eukaryotic cells divide.

When we talk about division we're talking about replication of those cells.

So how do the cells go from being one cell to creating a copy of that cell and being two.

Bacteria divide by a process called binary fission.

So that picture there is showing us you've got one bacteria cell and it divides, makes a copy of itself, and now we've got two bacteria cells.

That process of division is called binary fission.

Now eukaryotic cells do the same thing.

So they can make copies of themselves, but that process is called mitosis.

So the process by which prokaryotic cells divide is called binary fission.

The process by which eukaryotic cells divide is called mitosis.

Now we're going to look at the cell wall.

So prokaryotic cells have a cell wall made of a substance called peptidoglycan.

And you can see on this picture of the bacteria you've got the cell membrane labelled, and then you've got the cell wall that runs on the outside of the cell membrane.

In eukaryotic cells, plant cells do have a cell wall but it's not made of peptidoglycan, it's made of a substance called cellulose.

Yeast cells also have a cell wall, but animal cells do not have a cell wall.

Right, let's check our understanding.

So first question, how do prokaryotic cells divide? A, meiosis, B, mitosis, or C, binary fission? That is C, binary fission.

Really well done if you got that.

Which sub-cellular structure does a prokaryotic cell not contain? A, mitochondria, B, ribosomes, or C, cytoplasm? This is A, mitochondria.

Remember, prokaryotic cells do contain ribosomes and cytoplasm but they don't contain membrane bound organelles.

Next question, true or false.

All eukaryotic cells contain a cell wall and a cell membrane.

True or false? And then once you've decided that you justify that answer.

So A, animal cells contain a cell wall and a cell membrane, or B, animal cells do not contain a cell wall.

Okay, let's see if you got that right.

The first part is false.

Not all eukaryotic cells contain a cell wall.

And the reason for that is because B, animal cells do not contain a cell wall.

Plant and yeast cells do that are eukaryotic, but animal cells do not.

Next question, true or false? Prokaryotic cells are bigger than eukaryotic cells.

True or false? And then justify your answer.

A, prokaryotic cells are five to 100 micrometres, or B, prokaryotic cells are one to five micrometres.

Have a go.

So the first part is false.

Prokaryotic cells are not bigger than eukaryotic cells, and this is because prokaryotic cells are one to five micrometres.

Eukaryotic cells are five to 100 micrometres.

Amazing job if you remembered that.

That was very specific.

So really good work.

It is time for us now to move on to our third and final task.

And your job to begin with is to complete this table to compare the features of prokaryotic and eukaryotic cells.

And we're going to be looking at the membrane bound sub-cellular structures, DNA, so where the DNA is located, the size of the cells, and be specific there, try and give the actual sizes, the type of cell division and naming that, and also whether or not those organisms have got cell walls.

So pause the video now, give it your best go, and then press play when you're ready to go through the answers.

Okay, let's go through the answers.

So for membrane bound sub-cellular structures, the prokaryotic cells do not have any membrane bound sub-cellular structures, but eukaryotic cells do have membrane bound sub-cellular structures.

And some examples are the nucleus, the mitochondria, and chloroplasts.

Now you might have also said that chloroplasts are only found in plant cells, which would be amazing if you have put that.

Moving on to DNA, the DNA in a prokaryotic cell is floating in the cytoplasm, whereas in a eukaryotic cell the DNA is found inside the membrane bound nucleus.

Now make sure that you have corrected any work, added in any missing detail.

If you need to pause the slide now and press play to go through the rest of them, then please do, and then pick up when you're ready.

Let's do the next view.

So comparing the sizes, prokaryotic cells are smaller, in general between one and five micrometres, whereas eukaryotic cells are bigger, between five and 100 micrometres.

Cell division, prokaryotic cells divide by a process called binary fission, whereas eukaryotic cells divide by a process called mitosis.

And cell walls, in prokaryotic cells, the cell walls are made of a substance called peptido, sorry, peptidoglycan.

Absolutely amazing if you remembered that word 'cause that's a very long word.

And eukaryotic cell walls, animal cells do not have a cell wall, whereas plant cells do have cell walls and they are made of cellulose.

Okay, your next task is to use these diagrams to answer the questions below.

So the first question is to identify three similarities between prokaryotic cell and the eukaryotic cell in the diagram.

And then the second part is to identify three differences between the prokaryotic and the eukaryotic cells in the diagram.

Pause the video now and give it your best shot, and press play when you are ready for me to go through the answers.

Let's go through the answers then.

So I'm gonna bring up some similarities between these two cells.

You might have written these in different orders, but as soon as I say something that you've got you can just mark it off as correct.

So we've got a bacteria cell here and we've got a plant cell.

So the first similarity is that they both have cytoplasm.

They also both have a cell membrane.

They both have got DNA.

We just can't see the DNA but it is inside the nucleus of the plant cell.

They do also both have ribosomes.

You might also have written that they've both got cell walls and that would be 100 percent correct as well.

Now moving on to three differences between the prokaryotic and the eukaryotic cell.

The prokaryotic cell has no nucleus, or you could say the DNA is free in the cytoplasm.

The prokaryotic cell has also got no mitochondria.

The prokaryotic cell has a loop of DNA.

The prokaryotic cell is smaller.

So look over your answers now.

Correct anything that you might need to.

Absolutely amazing if you managed to get three similarities and three differences.

That is really brilliant work.

Well done.

That is the end of our lesson today on prokaryotic and eukaryotic cells.

I think you've done an amazing job.

Really, really good work.

I'm just gonna go through a summary now of everything that we've been through.

So to begin with, we said that prokaryotic cells do not contain a membrane bound nucleus.

We said that bacteria were prokaryotic cells.

Eukaryotic cells do contain a membrane bound nucleus, and the examples were animal, plant and fungi cells.

We said prokaryotic cells are smaller, they have fewer sub-cellular structures and divide by binary fission.

Whereas eukaryotic cells are bigger, they have more sub-cellular structures and they divide by mitosis.

There's an exit quiz for you to finish at the end of the lesson.

Give it your best go.

I really, really look forward to seeing you next time with Oak Academy.

Bye.