Lesson video

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

My name's Mrs. Bowes.

I'm really, really looking forward to the next lesson with you.

To make sure that you're ready to learn, have a pen and some paper and then we can get going.

The title of today's lesson is specialised plant cells, and the learning outcome is to identify specialised plant cells, describe the structure of specialised plant cells and relate this to their function.

This is a science lesson and it comes in the Key Stage 3 topic called cells.

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

The keywords that are going to help us to access the learning in this session are photosynthesis.

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

Chlorophyll is a green pigment that absorbs sunlight and is found in the chloroplasts.

And active transport is where particles are moved from an area of low concentration to an area of high concentration.

So the three keywords for today's lesson are photosynthesis, chlorophyll and active transport.

But our lesson today on specialised plant cells is going to follow this order.

So to begin with, we are going to identify some specialised plant cells from diagrams. Then we will state the function of those different specialised plant cells.

And finally, to finish off, we will explain how cell structures link to their function in specialised plant cells.

But to begin with, let's look at some diagrams and identify some specialised plant cells.

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

So by specific functions, I mean specific jobs.

So all of the specialised cells that we're going to look at today in plants, they all have a specific function and because of that, they have specific features that enable 'em to carry out that function.

But just to take it back to basics, let's look at this picture of a plant.

And you should know there's three main parts of a plant.

The first part is the stem, and that provides support and it transports water and nutrients around that plant.

Then at the bottom of the plant, you've got the roots.

And you can see here the roots are embedded within the soil and the job of the roots is to absorb water and nutrients.

So once the plant has absorbed water and nutrients from the roots, it will then travel up the stem and eventually, we'll get to the leaves.

The leaves absorb sunlight and they also let gases into and out of the plant.

So water travels from the roots up the stem and then eventually will get to the leaves.

Those were three bigger parts of the plant.

Today we're gonna talk about specialised cells.

Cells are a lot smaller.

We would need a microscope to see them.

This is a picture of one type of specialised plant cell.

Do you know what this specialised plant cell is? Maybe you remember it.

Okay if you didn't.

This is a root hair cell.

Now, funnily enough, a root hair cell we find in the roots of plants and the roots penetrate into the soil in all directions.

Remember, their job is to absorb water and minerals from the soil.

So the first specialised plant cell we're going to look at is a root hair cell found in the roots and they have this really particular shape with quite a long projection that comes out of it.

This is another type of specialised plant cell.

Any ideas what this one might be? This is called a palisade cell.

Really, really well done if you knew that.

Some of you might have just looked at this picture and thought, oh, that's a plant cell because when you learn about cells, often that picture on the screen is the the plant cell that you will learn about, but it's actually a specific type of plant cell and it's called a palisade cell, which you find in the leaves of plants.

So here we find the palisade cells on the top sides of leaves.

Now, this one is really hard.

Is there anybody that knows what this type of cell is? I wouldn't expect to know this.

This is called a xylem cell.

And xylem cells are found in the stem of the plant and their job is to transport water up through the plant.

Again, this one's very tricky.

Anyone know what this cell is? This is called a phloem cell.

And again, like the xylem, the phloem is also found within the stem of the plant.

So the four types of specialised plant cell we've spoken about are the root hair cell, the palisade cell, the xylem and the phloem.

Why do you think that leaves have veins? Because if you've ever looked at a leaf up close, like in this picture here, you can see that there are little veins that run across the leaves.

Why do you think that they are there? Well, actually, those veins are called the vascular bundle.

And the vascular bundle contains the xylem and the phloem and they transport water, glucose and minerals around the plant.

Now, as humans, we have veins and arteries that we can see underneath our skin, which carry blood around our body.

And plants don't have blood but they do still have the vessels which are contained within their vascular bundle that transport water, glucose and minerals.

Right, let's see how much we have understood so far.

So I'm gonna ask a series of questions.

There might be some multiple choice answers for you to pick from, or you might just have to come up with the answer on your own.

Give it to your absolute best.

It doesn't matter if you get it wrong, but let's begin.

So the first question is what cell is this diagram showing? A, xylem, B root hair cell, or C, palisade cell? Now, this is our palisade cell.

It is C.

Remember, I said to you at the beginning of the lesson that this cell is what we would normally kind of look at when we say this is a plant cell but actually, it is a palisade cell.

It's a specialised plant cell.

Next question, what cell is this diagram showing? A, xylem, B, root hair cell, or C, phloem? This one is B, the root hair cell.

Remember I said the root hair cell has that long projection that comes out of it? Really well done if you remember that.

Next question, what cell is this diagram showing? A, xylem, B, phloem, C, root hair cell.

This one is A, it is the xylem.

And then finally, what cell is this diagram showing? A, xylem, B, phloem, or C, palisade cell? This is B.

It is the phloem.

To distinguish the difference between the xylem and the phloem, the phloem has got those little sieve plates that run upwards through it that have the little holes within it.

Amazing job if you managed to correctly identify those cells.

We are now ready to go through our first task together.

So using a line, match each picture of the specialised plant cell to the correct name.

This shouldn't take you too long, nice and simple to get going.

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

Okay, so we're going from the names on the bottoms and we're starting from left to right.

So that is your xylem cell.

The phloem cell, remember is the one that has the kind of discs within it with the holes.

The root hair cell is the one that has the long projection coming out of it.

And then our palisade cell is what we would typically use to describe the features of plant cells.

Give yourself a mark if you managed to get those correct and correct anything you didn't.

Amazing work.

We are ready to move on.

So we now know how to identify specialised plant cells and we are now going to state the function of those specialised plant cells that we can now identify.

So remember that this cell here is our palisade cell.

The function of palisade cells is to absorb energy for photosynthesis.

And photosynthesis is an extremely important process.

It's how plants are able to make glucose, which is a sugar.

So it's the food for the plant.

We get our food as humans from eating food and drink but plants use photosynthesis to make their glucose.

So that picture there is showing you that the palisade cell absorbs light energy from the sun.

And there are many palisade cells in the upper surface of leaves to absorb as much light energy as possible.

So if that was a leaf, all of the palisade cells are packed at the very top layer of the leaf, and that's so that they can absorb as much light as possible.

This is a root hair cell, that long projection.

The function of the root hair cell is to absorb water and minerals from the soil.

So you can see here on that long projection there's loads of water and minerals that are constantly being absorbed by the roots.

Now, the xylem, the xylem transports water from the roots up the stem to other parts of the plant.

So if you remember that water and minerals are absorbed in the roots, that's the job of the root hair cells, well, once that water has been absorbed, it then needs to travel from the roots, up the xylem to the rest of the plant.

So the water moves only in one direction in the xylem from the roots up through towards the leaves.

So that would be the direction it travelled through the xylem.

But if you look at it next to a plant, the water would only travel in one direction from roots up towards the leaves.

The phloem, on the other hand, transports sugars from the leaves to the rest of the plant.

Now, remember what I said just a couple of minutes ago that the leaves absorb light for photosynthesis while sugars are made through photosynthesis, and that occurs in the leaves.

So the sugar is made in the leaves and then it has to be transported to every single cell in the plant.

The reason why sugars need to get to every single cell in the plant is because all cells respire and sugar, glucose is needed for respiration.

Those sugars need to get to every cell in the plant.

So therefore, it needs to move both up and down because it's being made in the leaves.

So if that was the phloem, the sugars move both up and down in both directions, and it would look like that if we were looking at the plant.

Okay, let's see how much of that we have understood and remembered.

First question, what is the function of the root hair cell? A, the cells where most photosynthesis takes place.

B, to absorb water and minerals from the soil.

Or C, to transport water from the roots to the rest of the plant.

Hopefully here you've got B.

The job of the root hair cell is to absorb water and minerals from the soil.

Really good if you remembered that.

Next question, what is the function of the palisade cell? A, absorb sunlight as most respiration takes place here.

B, absorb sunlight as most photosynthesis takes place here.

Or C, absorb water as most photosynthesis takes place here.

Now, these answers are are quite similar, so just look at the wording in particular.

I'll give you a little bit of time to think about this.

So you should have got B for this one.

Remember, palisade cells absorb sunlight and that's because photosynthesis takes place here.

Next question.

What is the function of the xylem? A, to transport sugar and minerals from the leaves around the plant.

B, to transport water from the leaves to the roots, or C, to transport water from the roots to the rest of the plant.

Now again, this one was a bit trickier because the answers are relatively similar but you should have had C for this one.

The xylem transports water, first of all, and the direction is from the roots to the rest of the plant in that one direction.

Amazing if you got that one right.

And then what is the function of the phloem? A, to transport sugar from the leaves to the rest of the plant.

B, to transport water from the leaves to the roots, or C, to absorb water and minerals from the roots.

And this one is A, the phloem transports sugar from the leaves to the rest of the plant.

Amazing.

Okay, now a little bit different.

You are going to complete the sentences by filling in the word gaps.

So the first one, the xylem transports something from the roots up to other parts of the plant.

The missing word there you should have is water.

Next one, the phloem transports something and minerals from the leaves to the rest of the plant.

This one is sugar.

Hopefully we're on a roll now.

Last one, the something absorbs water and minerals from the soil.

This is the root hair cell.

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

These are gonna help you with our next task, which we are ready to now complete.

So for task number two, you need to complete the table showing types of cell and their function.

So in one column, you've got the cell name, and in the other column, you've got the function.

Now, if you've been given the name of the cell, your job is to complete the function in as much detail as possible.

If you've been given the function, you need to identify the specialised cell that that is the function of.

So pause the video now, have a really good go at this and then press play again when you're ready to get going.

Amazing job.

Let's go through the answers.

So the function of the root hair cell is to absorb water and minerals from the soil.

Which cell traps light for photosynthesis? That is the palisade cell.

The function of the xylem is to transport water from the roots to the rest of the plant.

And the cell that transports sugar and minerals around the plant is the phloem.

If you need to pause a video now to improve your work or correct anything, please do and then we will carry on with the rest of the lesson.

Well, you are doing an amazing job.

We have identified our specialised plant cells.

We know the function of our specialised plant cells.

And now we're moving on to the final part of our lesson, which is we are gonna explain how the cell structures link to their function.

So we're going to start with our palisade cell.

Now remember, the function of the palisade cell was to absorb sunlight for photosynthesis.

Now, the first feature of a palisade cell that makes them excellent at absorbing sunlight for photosynthesis is that they contain many chloroplasts.

And you can see that the chloroplast is labelled on this palisade cell here.

They're is specific subcellular feature that animal cells do not have within their cells and that's because animal cells don't photosynthesize.

Plants do photosynthesize and photosynthesis occurs in the chloroplasts.

So palisade cells are packed with chloroplasts so that as much photosynthesis can take place.

And these contain a green pigment called chlorophyll that can absorb sunlight, and photosynthesis takes place in the chloroplasts.

So you've got the chloroplasts and they contain this green pigment.

That is what makes plants look green.

And that green pigment is called chlorophyll.

The chlorophyll absorbs the sunlight and then that is where photosynthesis takes place.

So the first thing we need to know is that palisade cells have got lots and lots of chloroplasts that contain chlorophyll.

The second thing we need to know is that palisade cells are found at the very tops of leaves so that they can absorb as much energy from the sun as possible.

And because they're placed at the top of the leaf, they're able to absorb more light than if they were placed anywhere else.

Imagine if you had lots of palisade cells at the bottom of leaves, they wouldn't get as much direct sunlight and therefore, having them all packed right at the top means they're constantly trying to absorb as much sunlight as possible.

Now, linked to the last thing we've just said, not only are the palisade cells located at the tops of leaves, they've also got this column shape.

Now, palisades are the column shaped so that they can be packed really closely together at the top of the leaf.

It means that you can put as many of these palisade cells in as small a area as possible because they have a column shape.

The more palisade cells that you have, obviously, the more sunlight that can be absorbed, and the more photosynthesis will take place.

So moving on now to our root hair cell.

The outer surface of a root is covered with many root hair cells.

So if that was the root network that a plant or a tree had, if you took one section of that root, so one root branch and zoomed in, then every single part of that root would be covered in many, many, many root hair cells.

So every single surface of the root is covered with root hair cells.

So what about the root hair cell makes it excellent at absorbing water and minerals? Well, not only are there many, many root hair cells that cover all the surface area of the roots, each root hair cell also have this long, thin projection, which increases the surface area for absorption of water and minerals.

The more surface there is for the water and minerals to diffuse or be actively transported through, the more can get into the root hair cell.

So the job of the root hair cell is to try and provide as much surface as possible for the water and minerals to get into.

And this long, thin projection increases that surface area.

They also have a very large vacuole to store as much water as possible.

And if you look at that little subcellular structure there, that's called a mitochondria.

There are many mitochondria in root hair cells because they release energy, which is needed for the active transport of minerals from the soil.

Aerobic respiration takes place inside of the mitochondria.

And one of the things that's released in aerobic respiration is energy.

Any cell that needs energy for some part of its function will have mitochondria.

And the root hair cell needs energy because it's actively transporting minerals from the soil, which is an energy requiring process.

So therefore, there are lots of mitochondria in the root hair cells to release that energy for active transport.

Okay, so let's see if we can answer these questions about the features of those specialised cells and how they relate to their function.

So first question, where are palisade cells located in a plant? A, bottom of the leaf, B, top of the leaf, or C, roots? This is B, they're at the top of the leaf to absorb as much sunlight as possible.

For photosynthesis to occur, palisade cells have a lot of which subcellular structure? A, ribosomes, B, mitochondria or C, chloroplasts.

This is C, it is the chloroplasts.

Remember, photosynthesis takes place inside the chloroplasts.

What is the name of the green pigment that absorbs light? A, chlorophyll, B, chloroplasts or C, vacuole? This one is A, it is the chlorophyll.

Hopefully we're on a roll.

We're doing really well.

Another question, why is it useful that palisade cells have a column shape? A, so that they can be far apart.

B, so that they can be closely packed together.

Or C, so that they can hold as much water as possible? This one is B.

The column shape means they can get as many of those palisade cells as closely packed together as possible to absorb as much sunlight as possible.

Really good if you remembered that.

Which statement explains why root hair cells have a large vacuole? A, to increase surface area to absorb more water.

B, so that they can absorb more light.

Or C, so that they can hold as much water as possible.

Remember, the vacuole is so that they can hold as much water as possible, which is C.

Which subcellular structure in a root hair cell releases energy for active transport? A, mitochondria, B, vacuole, or C, chloroplasts.

This one is A, mitochondria.

Respiration occurs in the mitochondria, which releases energy.

Well done if you got that one.

And finally, which is not a feature of root hair cells? A, long projections to increase surface area.

B, lots of chloroplasts to absorb light.

Or C, large vacuole to store water.

This one is B.

Remember, root hair cells, they are in the soil.

Chloroplast is where photosynthesis takes place.

You don't need chloroplasts in the root because there's no light, there's no photosynthesis taking place.

So B is the correct answer for that one.

Absolutely amazing work so far.

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

So some questions for you to answer here in full sentences.

So palisade cells contain a lot of which subcellular structure? Ii, what process takes place inside this structure? And finally, describe how the structure of palisade cells helps them to carry out photosynthesis using the keywords below.

I'm sure you're gonna do a really good job of this.

Pause the video now, give it a go and then press play.

And I will be there to go through the answers with you.

Okay, so remember to mark your work as we go.

And we should have done this in full sentences.

So for the first one, you should have palisade cells contain a lot of chloroplasts.

And then the second one.

Photosynthesis takes place in the chloroplasts.

We're going to move on to the third question.

So palisade cells contain lots of chloroplasts that absorb sunlight for photosynthesis.

That's the first feature.

You might have written these in a slightly different order.

As long as you've got the features and what they're for, you can mark them off as we go.

The second feature is that the palisade cells are found at the tops of leaves.

This means they absorb more sunlight for photosynthesis.

And then finally, the third thing.

Palisade cells have a column shape, which means they can be packed closely together.

If you need to pause the video now to give yourself a little bit of time to just correct anything or add in any detail, please do and we will pick up the next task once you have finished.

So part B of task three, what type of specialised cell do plant roots have? And then i, use the sentence prompts to explain how the features of root hair cells relate to their function.

So you've got some sentence starters there and you need to complete the sentences.

The first one is root hair cells have long projections to.

The second one, root hair cells have lots of.

You need to fill in that word gap so that.

And then finally, root hair cells have a large vacuole so that.

I'm sure, again, we're gonna do a really, really good job of this.

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

Okay, so the first one.

Plant roots have specialised cells called root hair cells.

And then completing these sentences.

Root hair cells have long projections to increase their surface area so they can absorb more water.

You might have also written and minerals there, which is fine.

The second one, root hair cells have lots of mitochondria so that they release energy for the active transport of minerals into the root.

And then the third one.

The root hair cells have a large vacuole so that lots of water can be stored.

Again, there's quite a lot of really important words here.

So the idea of increasing the surface area, if you haven't written about that, add that in.

The reason why there's lots of mitochondria is to release energy and you might have missed off that that's for the active transport of minerals.

So just give yourself a bit of time now to make sure you've got everything within your answers that you do need.

That is the end of today's lesson.

I hope that you have enjoyed it and also learned lots as well.

I'm just gonna do a really, really quick summary of everything that we've learned.

So the first thing we said was that different parts of a plant have got specific functions, and there're three parts were the roots, the stems, and the leaves.

We then said that cells can be specialised to contain structures that help them to carry out their functions.

We looked specifically at root hair cells.

We said they were long, they had thin projections that increased the surface area and this means that they can absorb more water.

They also have lots of mitochondria that release energy for active transport of minerals, and they also have a large vacuole to store water.

Photosynthesis takes place in the chloroplasts.

Palisade cells have many chloroplasts and are found at the top of leaves.

And that palisade cells are column shaped so that they can be closely packed together.

There is now an exit quiz for you to have a go at.

I'm sure you're gonna do a brilliant job.

You've done an amazing job so far throughout the lesson.

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

Bye.