Lesson video

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

My name is Mrs. Bowes.

I'm really looking forward to today, so make sure that you're ready to learn.

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

The title of today's lesson is Specialised Animal Cells.

And the outcome is to identify specialised animal cells, describe the structure of specialised animal cells, and relate this to their function.

This is a science lesson, and it comes in the key statutory topic called Cells.

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

The key words for today's lesson are respiration.

Respiration is a chemical reaction that releases energy.

Every single cell in our bodies is respiring and it releases energy, which is what keeps us alive.

Aerobic means with oxygen.

Photosynthesis is a chemical reaction that plants use to make their own food.

So the key words for today's lesson are respiration, aerobic, and photosynthesis.

The lesson structure today is going to be as follows: So, the first thing that we're going to learn about is to identify some specialised animal cells from diagrams, and then we're going to state the function of those different specialised animal cells.

And then to finish with, we will explain how the structures of those specialised cells link to their function.

But to start, let's just identify some specialised animal cells.

Let's get going.

So, first of all, there's three pictures on this slide.

What do you think these images are showing? Have any idea? Well, the first picture is showing you some sperm cells under a microscope.

The second picture is showing you some cheek cells.

And the final picture is showing you some red blood cells.

These are all specialised cells that you would find in animals.

Specialised cells have structures that allow them to carry out specific functions.

So each of those different cells has a different function, a different job, and because of that they have different structures.

Any idea what this specialised cell could be? I'll give you a clue.

It was one of the ones on the previous slide.

It is a red blood cell.

A red blood cell is a specialised cell, it's got a specific function; and because of that it's got specific features, and that could be the shape of it and the subcellular structures that are contained within the red blood cell.

Now, red blood cells are found in the blood and they form part of the circulatory system.

So, this picture that you can see on the slide now is showing you a human body and all of the different arteries and veins and the heart, and also in there will be capillaries as well.

And it's showing how the red blood cells travel around the body as part of the circulatory system.

A red blood cell is the first example of an animal specialised cell that we are gonna talk about today.

Any ideas what this specialised cell might be? This is a nerve cell.

And nerve cells form part of our nervous system.

And the nervous system controls pretty much everything that we do.

So in this picture, we can see the nervous system consists of the brain, the spinal cord, and the nerves.

So that one picture of the nerve cell on the left hand side is just showing one nerve, but in reality we've got nerves that connect to each other going across all parts of our body, and that is what allows us to talk, to think, to move.

They're very, very important.

And if you notice, the the diagram of the nerve cell looks quite different to the picture of the red blood cell, and that's because it's got different shape and different features to make it very good at its job.

What do we think this specialised cell is? This is a sperm cell.

And sperm cells are produced by males and they are needed to begin the process of reproduction, so they form part of the reproductive system in humans.

Any ideas what this specialised cell might be? This is an egg cell.

And again, eggs are one of the sex cells, but this time they are produced by females, and they combine with the sperm in fertilisation to produce an embryo.

So the sperm and the eggs are both sex cells, but they are specialised cells, and they are part of the reproductive system.

And then this one, this is a really, really tricky one.

Have you any idea what this specialised cell or these specialised cells, there are four of them, what they could be? These are called ciliated cells.

Now, ciliated cells line all of our airways, which includes the lungs and the trachea.

And this forms part of the respiratory system.

So just to go over all of those.

The specialised animal cells that we are going to be looking at today are the red blood cell, the nerve cell, the sperm cell, the egg cell, and the ciliated cells.

Now, notice when you look at these pictures, all those specialised cells have very different shapes and within them they have different subcellular structures, and that is what makes them very good at carrying out their function.

We will look at that later on in the lesson.

We should be ready now to check our understanding.

So I'm gonna ask some questions.

There will be some options or sometimes there might not be options, but you need to try and give me what you think is the correct answer.

And I'm sure you're gonna do really, really well.

So the first question is: Which cell is this diagram showing? A, an egg cell; B, a nerve cell; or C, a red blood cell.

This is C.

It is a red blood cell.

Amazing if you got that.

Next question.

Which cell is this diagram showing? A, a sperm cell; B, a nerve cell; or C, an egg cell.

This one is A.

It is a sperm cell.

Next question.

Which cell is this diagram showing you? Nerve cell, A; B, a sperm cell; or C, ciliated cell.

This is our ciliated cell, so it is C.

And which cell is this diagram showing you? A, A nerve cell; B, a ciliated cell; or C, A sperm cell.

Are we on a roll? This one is A.

It is our nerve cell.

And then finally, which cell is this diagram showing? A, a sperm cell; B, an egg cell; or C, a red blood cell.

This is our egg cell, so it's B.

Amazing if you manage to recognise and identify all of those specialised cells.

Really, really good work.

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

Now, your job is to name the specialised cells in these pictures.

So you just have to write the name next to the cell.

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

Right.

Let's see how we did.

A is our red blood cell.

B is the nerve cell.

C are the ciliated cells.

D is the egg cell.

And E is the sperm cell.

Absolutely brilliant if you managed to remember all of those.

Maybe just check your spelling now and see if you've spelled all the names correctly.

You can pause the video if you need to and then press play and we'll carry on for the rest of the lesson.

Right, so now we should be able to identify specialised animal cells from diagrams. And we're going to move on to state the function of those different specialised animal cells.

The function of something is the job of that cell.

So what does that cell do in the body? What is its job? So we're gonna start with our red blood cell.

When we breathe in oxygen from the air, that oxygen travels down our trachea and into our lungs.

And the oxygen diffuses into the red blood cells in the lungs.

So if that's our red blood cell, it will have lots of oxygen contained within it.

And the function of the red blood cells is to deliver that oxygen to all cells of the body for respiration.

So every single cell in our body is respiring, it needs oxygen for respiration.

And in respiration you release energy, which is what keeps us alive.

So the red blood cells are very, very important because they deliver the oxygen to cells of the body for respiration.

And red blood cells move around the body in the blood vessels, which you can see in this picture, and it forms part of the circulatory system.

Moving on to nerve cells now.

This is showing you two different nerve cells.

The function of nerve cells is to transmit, which means to carry, electrical impulses throughout the body, and they form part of the nervous system.

So these nerve cells, they have to carry and transmit electrical impulses along them and pass them between different nerve cells.

So you might be thinking: "How does that happen?" Well, let's say an impulse arrives in the first nerve cell.

The impulse here is represented by the purple lines.

So we've got the impulse arriving, and then the impulse travels down the whole length of the nerve cell.

And you can see that both ends of the nerve cell are branched, which connects one nerve cell to another.

So that impulse can then travel from the end of one nerve cell to the start of another nerve cell.

So the branched ends connect different nerve cells, and then that impulse can just travel down the connecting nerve towards the end of that nerve cell.

So the function of the nerve cells is to transmit electrical impulses throughout the body.

Here we've got our sperm cell.

Sperm cells are the male sex cells, and they have to swim to meet the egg before fertilisation can occur.

Now, there are actually millions of sperm cells that are released, but only one of those sperm cells is able to fertilise the egg.

So you can see in that picture there we've got more than one sperm.

In reality there are millions of sperm, but only one of them is going to be able to get to the egg and fertilise that egg.

So the sperm cell has to swim towards the egg before fertilisation can occur.

Now, here we've got a sperm and the other cell is the egg.

So we're gonna look now what's the function of the egg cell.

Now, the egg cells are the female sex cell, and they join with the sperm during fertilisation to form that embryo.

So once the sperm cell has swam towards the egg, the egg has to be ready to fertilise with the sperm so that a zygote can form and then an embryo will develop.

So that very first cell that occurs after fertilisation is the zygote, and then that will divide until it forms an embryo.

These are our ciliated cells.

Remember ciliated cells line the airways.

And you can see that the ciliated cells are covered with tiny little hairs, and the tiny hairs move together to push mucus out of the airways.

So sometimes when you've got a cold or a cough and you cough, you can hear crackling, and that sometimes is mucus buildup.

And the job of your cilia is to try and move that mucus up and out of your lungs, and they've got these little tiny hairs on them that help them to do that job.

And they line all of our airways, again, to help us move that mucus up and out the lungs.

Right, we should be ready now to do a quick check for understanding how much have you remembered.

Remember, it doesn't matter if you get any wrong.

Just give it your 100% best.

So first question.

What is the function of the sperm cell? A, to swim and join with the egg for fertilisation to occur; B, to send electrical impulses around the body; or C, to carry oxygen around the body for respiration.

This one is A.

It is swimming to try and find the egg.

Next question.

What is the function of the red blood cell? A, to move mucus up and out of the lungs; B, to carry oxygen around the body for respiration; or C, to combine with the sperm during fertilisation and produce an embryo.

Hopefully this one was nice and easy.

This is B.

Red blood cells carry oxygen around the body for respiration.

And this question: What is the function of a nerve cell? A, to carry oxygen around the body; B, to move mucus up and out of the lungs; or C, to send electrical impulses around the body.

This one is C.

It sends or they send electrical impulses around the body.

Amazing if you're getting these right, well done.

Okay, last question.

Little bit harder this one because you don't have the same prompts.

But can you complete the sentences? So the first sentence is: An something cell is the female sex cell.

It joins with the sperm during fertilisation to produce an embryo.

We do that one first.

What do we think that is? That is an egg cell.

Amazing if you remembered that.

And then the last question: The something cells line the airways and move mucus up and out of the lungs.

What is that missing word? This is the ciliated cells.

Brilliant work if you managed to get all of those right, well done.

I think now we are ready to move on to our second task.

And your job here is to complete the table, showing the types of cells and their function.

So it could be that you've been given the function and you need to write the name of the cell or you've been given the name of the cell and you need to complete the function in as much detail as you can.

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

Right.

Let's get going.

So the first cell, swim to the air where fertilisation occurs, that's our sperm cell.

Transmit electrical impulses around the body, they are our nerve cells.

The function of the ciliated cells is that they line the airways and move mucus up and out the lungs.

And then finally, the function of the red blood cells is to carry oxygen around the body for respiration.

Absolutely amazing if you managed to identify the cells from the function and then write the functions for the latter too.

If you need to pause the video to just add anything into your work, please do, and then press play when we're ready to carry on with the lesson.

So we've reached our third and final learning cycle.

So now we can identify specialised animal cells and we know their function.

We're now going to explain how the cell structures link to that function.

And for this we're talking about the shape of the cells and the subcellular structures that are contained within it.

So specialised cells have specific features that help them to carry out their function.

When you link a feature to an explanation, we use the words so that in our answer.

So we've got our feature, which could be, for example: Bears have got fur so that, and then the explanation.

So we would have: Bears have fur so that they are well insulated.

And this just makes sure that we link our explanation to our feature.

So we try and use the words so that to make sure that we explain what that feature does.

So the first cell we're going to look at is our red blood cell.

And remember the function of the red blood cell is that they carry oxygen around the body which is used for respiration.

Now, the features of a red blood cell are that they have a biconcave shape.

Biconcave means that it is a flat shape and it has dips on either side.

So a red blood cell is flat and it's got dips on either side, and that is called biconcave.

The reason why it has this biconcave shape is so that the cell has a large surface area to absorb more oxygen in the lungs.

Because we said that when you breathe in, the oxygen goes into the lungs, and that oxygen needs to get from the lungs into your red blood cells.

And the bigger the surface of the red blood cell, the more oxygen can diffuse into it.

The second feature of red blood cells that make them really good at carrying oxygen around the body is that they have no nucleus, this means that there's more space inside of that red blood cell to carry the oxygen.

So we're trying to make as much space as possible inside that red blood cell.

So we've taken out the nucleus.

Or there is no nucleus, it's not been taken out, there is just no nucleus.

And that means that you can fit more oxygen inside the red blood cell.

So both of these features are to get as much oxygen into the red blood cell as possible.

We're going to look at a nerve cell now.

Remember the function of a nerve cell is to transmit electrical impulses throughout the body.

The first feature of a nerve cell that makes them really good at that is that they have these branched connections at each end, which I did speak about previously.

And you can see on the diagram they've got these branched endings and they connect nerve cells together so that those electrical impulses can travel very, very quickly.

They're also long and thin so that they can carry impulses over long distances quickly.

So some nerves in our body are very, very long.

And obviously we are moving and making decisions every second of every day.

And those decisions, we don't even think about, they happen very, very quickly, and that's because our nerve cells are adapted to transmit electrical impulses extremely quickly.

They've also got something called a myelin sheath that surrounds the nerves so that the impulses can travel faster.

And the myelin sheath on these diagrams are like the little rectangles that are surrounding the longer part of the nerve cell.

Now moving on to our sperm cell.

Remember, sperm cells are the male sex cell.

Their job is to swim to meet the egg before fertilisation can occur.

So what features does the sperm cell have that makes them very good at swimming towards the egg cell and for fertilisation to occur? The first thing is that they have a tail.

This gives them a really streamlined shape and it enables them to swim towards the egg cell.

Secondly, just before you get to the head of the sperm there are many mitochondria so that lots of energy can be released for movement.

Mitochondria are the subcellular structure where aerobic respiration occurs.

In aerobic respiration, energy is released.

So a sperm cell has lots of mitochondria, so lots of energy can be released, and that is to provide energy for movement so that the sperm can get to the egg cell.

And then the third and final thing is that in the tip of the head there is a feature called an acrosome.

That acrosome contains enzymes so that the cell membrane can be broken down once the sperm meets the egg.

So the egg cell has got a membrane around it.

And as soon as a sperm gets to the egg, the head will fuse with the egg cell and the acrosome will release these enzymes that help break down that egg cell membrane so that fertilisation can occur.

And then moving on to our egg cell.

The egg is the female sex cell.

Its job is to join with the sperm during fertilisation to form an embryo.

So what features does the egg cell have that make it really good at its job? Well, the first thing is that the cytoplasm, which is the jelly-like substance that surrounds the subcellular structures, it contains lots of nutrients, and it has those so that the early embryo has got lots of nutrients so that it can grow.

And also the cell membrane changes after fertilisation so that no more sperm cells can enter that egg.

Remember, only one sperm can fertilise one egg.

So to stop more sperm from fertilising the egg, once one sperm has joined with the egg cell and the acrosome is releasing enzymes to break down that membrane, once fertilisation has occurred, the egg cell membrane changes so that no more sperm cells can fertilise that egg.

And then finally are ciliated cells.

Remember their job is to line the airways to help mucus move up and out of the lungs.

So we said that they've got these tiny little hairs on the top of them, and they are called cilia, and they move together, so in unison; so all of them might be upright, and then together they'll move to the side, and then they'll move back up again.

And they do that so they can move mucus up and out of the airways.

They sort of waft the mucus along.

We should be ready now to answer some questions.

Again, just give it your best go.

First question.

Which of the following is a feature of red blood cells? A, they have a tail; B, they have no nucleus; or C, they are long and thin.

This is B, they have no nucleus.

Remember no nucleus means they can pack more oxygen inside that red blood cell.

Next question.

Which of the following is not a feature of a nerve cell? A, have a fatty myelin sheath; B, have a tail; or C, they're long and thin.

This is B.

Nerve cells do not have a tail, that would be a sperm cell.

Well done if you got that.

What feature is on the tip of a sperm cell's head? A, a tail; B, tiny hair cells called cilia; or C, an acrosome containing enzymes.

Remember this is asking you what feature is on the tip of the sperm cells head.

This is C.

It is an containing containing enzymes.

Now, remember, the sperm cell does have a tail to help it swim, but it doesn't have tiny hairs called cilia, so it would not have been B.

But in the tip of the head is the acrosome.

Which part of the cell contains lots of nutrients? Sorry, which part of the egg cell contains lots of nutrients? A, cytoplasm; B, cell membrane; or C, the nucleus.

This is A, the cytoplasm.

Amazing if you remember that.

Really, really good work.

And then why does the acrosome in a sperm cell contain enzymes? A, to allow the embryo to grow; B, to break down the egg cell membrane; or C, to release energy for movement.

This is B.

It contains enzymes which break down the egg cell membrane.

Then a true or false question.

Egg cells change their membrane once fertilisation has taken place.

Is that true or is that false? And then justify your answer.

A, many sperm cells can enter the egg cell; or B, only one sperm cell can enter the egg cell.

You have to think about these two parts.

This is true.

Egg cells do change their membrane after fertilisation; and the reason that they do is because B, only one sperm cell can the egg cell.

Right, we are ready now to move on to our third and final task.

So you have got some questions to answer, please answer them in full sentences in as much detail as possible.

So question A is: Why do sperm cells have lots of mitochondria? B, why do sperm cells have an acrosome? C, why do sperm cells have a tail? And D, why are nerve cells long and thin? Pause the video now, give it your best go, and then press play when you're ready for me to go through the answers.

Okay, let's go through this.

So for A: Sperm cells have many mitochondria to provide energy for movement.

You might also have written in there that aerobic respiration occurs inside the mitochondria, which releases energy.

And that is amazing if you've added in that extra detail.

But the key points are that the mitochondria provide or release energy for movement.

B: The acrosome contains enzymes so that the egg cell membrane can be broken down.

And then C: Sperm cells have a tail so that they can swim to the egg cell for fertilisation.

And D: Nerve cells are long and thin so they can send impulses over long distances quickly.

If you need to pause the video to add any extra detail into your answer and mark yours, please do.

Amazing job if you managed to get those correct.

Let's move on to the next part of our task.

So answer each question using the given keywords.

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

Okay, so the first one we're talking about the structure of ciliated cells and how they relate to their function.

The first thing is that ciliated cells have these tiny hairs called cilia that move together so that mucus can be moved up and out of the lungs.

How does the egg cell relate to its function? The egg cell membrane changes after fertilisation to stop more sperm entering.

Also, you might have written: The cytoplasm has lots of nutrients to help the embryo grow.

And finally: Describe how the red blood cell relates to its function.

Red blood cells have no nucleus so that they can carry more oxygen.

They also have a biconcave shape so they can absorb more oxygen.

If you need to pause the video to go through any of those answers, then please do, and then we'll pick up once you have finished.

That is the end of today's lesson on specialised animal cells.

I'm sure you've done an amazing job answering all of those questions, filling in the task sheets.

Really, really good work.

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

So the first thing we said is that specialised cells have structures that help them to carry out specific functions.

Nerve cells are long and thin, they have branched ends, and a myelin sheath to help them send impulses quickly.

Red blood cells have got no nucleus and a biconcave shape so they can absorb and carry as much oxygen as possible.

Sperm cells have a tail to swim and lots of mitochondria to release energy for movement.

In the head of the sperm is an acrosome containing enzymes to break down the egg cell membrane.

And then an egg cell membrane changes once fertilisation has occurred, and the cytoplasm is filled with nutrients to support a growing embryo.

So those are our specialised animal cells, and we have learned all about their structures and how they link to their function.

There's an exit quiz now for you to complete.

I'm sure you're gonna do an amazing job.

I've really enjoyed today's lesson.

I look forward to seeing you next time.

Have a good day, and bye.