Lesson video

Hello and welcome to this lesson from the Oak National Academy on aerobic cellular respiration.

We talked about cellular respiration earlier in this unit, and today we're gonna talk about a specific type called aerobic cellular respiration.

Hi there, I'm Mrs. Wheat, and by the end of today's lesson you'll be able to describe the reactants and products of aerobic cellular respiration and describe where it takes place.

Let's look at our keywords.

So the keywords we have, aerobic cellular respiration, cytoplasm, mitochondria, oxygen and carbon dioxide.

So on the next slide I'm gonna show you the definitions so you don't need to try and memorise all of them now, if you wanna pause, make some notes on them or just read through them to get yourself more familiar with them, all those options are fine.

So here are our definitions for our keywords.

Today's lesson is in two parts.

First of all, we'll talk about where aerobic respiration happens.

Then we'll move on and we'll talk about the reactants and products of aerobic cellular respiration.

But first of all, where it all happens.

In previous lessons in the unit, I've gone on and on about how important aerobic cellular respiration really is.

It's incredibly important, all living things do it.

It provides energy for life processes.

It's one of the seven key life processes that all living things do.

And today we're talking about a specific type of cellular respiration called aerobic cellular respiration.

Aerobic cellular respiration is a chemical process that happens inside the cytoplasm and mitochondria of cells.

I've got three cells here, can you recognise them? Can you tell me what type of cells they might be? One of them's a lot harder than the others, but I believe in you.

still have a go, pause the video here while you think about your answer, and then click play when you're ready to get back to the lesson.

Let's see if you're right.

So first of all, we have an animal cell.

You can tell it's an animal cell because it has a nucleus, it's got cytoplasm, it's got mitochondria and it's got a cell membrane.

In the middle, we have a plant cell.

You can tell it's a plant cell because it's got a nucleus, mitochondria, chloroplast in green.

It's got a vacuole, a permanent vacuole, a cell wall, and a cell membrane.

Really great job if you've got this last cell, it's a fungal cell.

You might not have heard of that one before and that's okay.

Let's look at the things it has in common with the animal cell and the plant cell.

It's got a nucleus, cytoplasm, cell membrane, mitochondria.

It's got a cell wall like a plant cell, but it doesn't have chloroplast.

So fungi are things like mushrooms and yeast.

And so this is the type of cell that belongs to that kingdom of organisms. So let's look at where aerobic cellular respiration happens in these types of cells.

So they all have mitochondria.

So aerobic cellular respiration happens in the mitochondria.

They all have cytoplasm.

So aerobic cellular respiration is also happening in the cytoplasm.

So what is cytoplasm? Maybe you remember from year seven cells lessons, cytoplasm is the jelly-like substance inside a cell where chemical reactions of the cell take place.

So here we've got a plant cell, we've got the cytoplasm labelled.

All of the other subcellular structures are suspended inside the cytoplasm.

Cytoplasm is mostly liquid, which is really useful 'cause that means that all the other chemicals are dissolved in it, which makes it super easy for chemical reactions to occur.

Right, let's look at the mitochondria.

So mitochondria are subcellular structures.

This means they are small structures inside cell, so they're smaller than cells.

Again, here's my plant cell.

Plant cells have got mitochondria as well because they also carry out aerobic cellular respiration.

Mitochondria are an important site of aerobic cellular respiration, right, let's see how you're doing.

Where does aerobic cellular respiration take place in the cell? Pause the video here and have a think whilst you come up with your answer.

Right, let's check those answers.

So the answers are A, the mitochondria and E, the cytoplasm.

Great work if you got that right.

Some cells need lots of energy to perform their function.

Have a think about what kind of cells those might be.

So which type of cells in the human body will need more energy, so more mitochondria, and which kind of cells in your body might need less energy and therefore less mitochondria? Pause the video whilst you think about that.

Great job, working hard trying to think back to year seven when you learned about cells.

It was a long time ago, so anything you might have remembered is really impressive.

One cell you might have come up with is a sperm cell.

Sperm cells need lots of mitochondria because they need lots of energy to swim to the egg in order to fertilise it.

Another cell you might have come up with is a muscle cell.

Muscle cells need lots of energy as well, and that's the one we're gonna focus on in this example.

I wonder what you came up with in terms of examples for cells that don't need very much energy.

Skin cells, for example, need relatively less energy than a sperm cell or a muscle cell.

Let's look at muscle cells in more detail.

Muscle cells contract and relax to move the skeleton.

This requires a lot of energy, which makes sense, right? Think about athletes like bodybuilders.

They need to eat a huge amount of food.

Food because that food is the fuel for aerobic cellular respiration.

So their muscle cells are working really hard, which means they need a lot of energy.

They have lots of mitochondria to carry out lots of aerobic cellular respiration.

So have a look at the muscle cell here.

You can see that it's got more mitochondria than the cells I showed you before.

That's to represent the fact that because this cell is so active and requires lots of energy to perform its function, it needs to be doing lots and lots of aerobic respiration.

So all those mitochondria are doing aerobic respiration, which providing lots and lots of energy for the muscle cell to do its thing, to contract and relax.

Okay, how are we doing? Let's take a moment now to check our understanding of everything we've just learned.

What would this animal cell need in order to carry out aerobic cellular respiration? Would it be A, chloroplasts? B, mitochondria C, a nucleus, D ribosomes.

So what do I need to add to this drawing of an animal cell in order for it to be able to do aerobic cell or respiration? Pause the video whilst you think about your answer.

It is B, mitochondria.

Great work, let's do our first practise task.

So number one, label the cytoplasm and one of the mitochondria in both cell A and cell B.

Number two, suggest why cell A has more mitochondria than cell B.

Pause the video here for a few minutes while you think about your answer really carefully and write it down.

Good luck, right, let's check your answers.

Here is the cytoplasm, the jelly-like substance that all the other structures in the cell are suspended in.

Here are the mitochondria, another site of aerobic cellular respiration.

Let's look at the answer for number two.

Suggest why cell A has more mitochondria than cell B.

The function of mitochondria is to carry out aerobic cellular respiration.

Aerobic cellular respiration provides energy for life processes.

Cell A has more mitochondria than cell B because it must have a function that requires more energy than cell B.

So maybe you had a guess about what that function could be like being a muscle cell.

Any of that would be fine as well.

Really, really good work.

So we've talked about where aerobic cellular respiration happens.

Now we're gonna look at the reactants and products of aerobic cellular respiration.

Aerobic cellular respiration is a series of chemical reactions.

You might remember from other science lessons that in a chemical reaction, something brand new is made.

So unlike a physical change, a physical reaction like ice melting into water, ice and water are the same thing.

They're both H2O, they're just in different states of matter.

Nothing fundamentally new is made when you melt ice, no atoms have been rearranged, but in a chemical reaction, atoms are rearranged, new substances are formed.

So aerobic cell respiration is lots of a series of those chemical reactions.

During chemical reactions, one or more substances are broken down.

These are the reactants.

I kind of like to think of those as ingredients.

You're starting with flour, with eggs, with sugar to make a cake.

They get mixed all together to make something brand new.

The cake or the products, one or more new substances are made.

These are the products.

So here's a general idea of what one looks like.

So A plus B, that arrow means reacts to make C plus D.

We've got the things before the arrow.

Those are our reactants, the things after the arrow.

Those are our products.

So that was just a quick recap for how chemical formula kind of work.

And we are gonna learn now of the reactants of aerobic cellular respiration and the products of aerobic cellular respiration.

Like any chemical process, aerobic cellular respiration has reactants and products.

So this is mainly happening in the mitochondria and cytoplasm of cells.

Let's zoom in on a mitochondria.

There we go now it's a bit bigger.

So the reactants, what we've got coming into our mitochondria and our cytoplasm are oxygen from the air that we breathe and glucose from food that we eat or for plants they don't eat, they photosynthesize.

So oxygen's coming from the air and glucose is coming from either eating or photosynthesizing, something like that.

Those are our reactants, our products leaving the mitochondria, leaving the cytoplasm are water and carbon dioxide.

Aerobic cellular respiration is not just one chemical reaction.

It's a series of chemical reactions that happen inside cells.

But it's useful to remember a word summary of reactants and product, right? So let's look at that word summary.

We have oxygen and glucose as our reactants before the arrow, so they react to make water and carbon oxide, oxygen, glucose, those are our reactants.

Water and carbon dioxide, those are our products.

Right now you're more towards the beginning of your scientific education.

So there isn't really time to go into the huge amount of detail every single scientific process we're gonna come across.

So this word equation is a huge simplification of what's really happening, but it does summarise what's going on.

If you're really interested in all the ins and out of aerobic cellular respiration then please pursue biology, pursue science at a higher level when you get the chance.

Let's check our understanding of what we just went through.

Two of the boxes below can be joined together to form a correct sentence to describe aerobic cellular respiration.

Draw a line to link the correct start of the sentence to the correct end.

Pause the video here, have a read through those.

Draw one line to connect the correct start of the sentence to the correct end of the sentence.

Let's check your answers.

So you should have joined, it's a series of chemical reactions, to, that takes place inside cells.

Great work if you got that.

Right, next one, which of the following is the correct word summary of aerobic, cellular respiration? Is it A, carbon dioxide plus water reacts to make glucose and oxygen? Is it B, glucose plus oxygen reacts to make carbon dioxide plus water? Or is it C, glucose plus carbon dioxide reacts to make oxygen plus water.

Pause the video here whilst you think about your answer.

Right, how did you do? Let's look at the answer.

It is B, glucose plus oxygen reacts to make carbon dioxide plus water.

Great work everyone.

So now we're gonna look at each of the reactants and products of aerobic cellular respiration in turn.

One reactant of aerobic cellular respiration is oxygen.

Let's look at the word aerobic cellular respiration.

So the beginning part here has specific meaning.

So the beginning part of the first word, aerobic, aero, means air and that comes from Greek.

So hopefully by remembering that that will give you a bit of a reminder for what one of the reactants of aerobic cellular respiration is.

It's oxygen which comes from the air aerobic.

So all kinds of different organisms do aerobic cellular respiration and they have different ways, different strategies of getting the oxygen they need.

So some animals get oxygen by breathing in air.

Not even all animals do that.

Fish, for example, they don't breathe, they don't have lungs, they've got gills.

So lots of different ways of getting that oxygen.

Plants don't breathe, they don't have lungs either.

So in plants the oxygen diffuses right into leaves through tiny holes on the onside of the leaf.

There are a variety of different strategies to get this oxygen, but all organisms need it if they want to do aerobic cellular respiration.

Let's talk about glucose now.

Another reactant of aerobic cellular respiration is glucose.

Again, there's lots of strategies that living things have in order to get the glucose they need.

Animals get glucose by eating and digesting carbohydrates.

So here we've got a chicken.

It looks like it's eating some grain.

So that grain is gonna go into the chicken's mouth through the rest of its digestive system and it's gonna break it down to release glucose.

That glucose is then used as the fuel in cellular respiration.

Plants get glucose by carrying out a chemical process called photosynthesis.

So in this picture I've got some cells.

Photosynthesis is a series of chemical reactions that happen inside some certain plant cells.

So we don't need to go into tonnes of detail about it now, you'll learn about it in a future unit in a different lesson.

But the reason I'm bringing it up now is to show you a contrast between animals and plants.

They both need glucose, but they both get it in really different ways.

So glucose is another really important reactant of cellular aerobic respiration.

Let's move on to the products then, carbon dioxide.

One of the products of aerobic cellular respiration is carbon dioxide.

Too much carbon dioxide is poisonous to cells.

Some animals excrete, that's getting rid of, carbon dioxide by breathing out.

In plants, carbon dioxide diffuses out of the leaves through holes in the underside of the leaf.

So again, there's different ways that different living organisms have of getting rid of carbon dioxide, but they all must get rid of it, otherwise it poisons their cells.

The final product of aerobic cellular respiration is water.

Water has many uses in living organisms. I can't possibly go through all of them here.

We're just gonna look at one.

So most of the cytoplasm in a cell is made up of water, which connects to the beginning part of our lesson.

Remember, the cytoplasm is the site of aerobic cellular respiration, living organisms excrete, that means get rid of excess water.

So in humans that means urinating.

In plants, that means water vapour leaving through those tiny holes at the under side of the leaf.

So again, living organisms have many different strategies for getting rid of this waste product.

Let's check to see if you understood that.

Put some of the words into the table to state the reactants and products of aerobic cellular respiration.

So the words you can choose from are mitochondria, oxygen, water, cytoplasm, carbon dioxide, nitrogen, glucose and animal cell.

Pause the video here, what you think about which of those words belong in each column of the table.

Let's see how you did.

So our reactants.

We should have oxygen and glucose, for our products, we should have water and carbon dioxide.

Well done.

So here is our last practise task of the lesson.

Keep going, you're doing so well.

You've asked a friend to look after your pet hamster whilst you're away on holiday.

This friend has never had a pet before so needs some instructions.

Using your knowledge of aerobic cellular respiration, explain the following as fully as you can.

Number one, why is it important that the hamster is fed regularly? Number two, why is it important to keep the hamster in a cage that's ventilated? That means it's got air holes in it.

Pause the video here whilst you think about your answer and write it down, then come back when you're ready to hear the answers.

Right, let's check those answers.

Why is it important that the hamster is fed regularly? The hamster needs food so that its cells have a supply of glucose.

Glucose is are reacting of aerobic cellular respiration.

Living organisms carry out aerobic cellular respiration to provide energy for life processes.

Number two, why is it important to keep the hamster in a cage that's ventilated? The cage needs to be well ventilated so that the hamster has access to oxygen.

Oxygen is a reactant of aerobic cellular respiration.

Living organisms carry out aerobic cellular respiration to provide energy for life processes.

Without ventilation, the hamster could run out of oxygen and not be able to carry out aerobic cellular respiration.

As the hamster respires, it produces carbon dioxide.

The buildup of carbon dioxide is poisonous to cells.

Without ventilation, carbon dioxide would build up in the cage and poison the hamster cells.

Good job on all your hard work.

That was the last practise task.

You can take a breath now and relax.

We've learned so much today about aerobic cellular respiration.

We're gonna recap it one more time to really help it stick in our minds.

Aerobic cellular respiration is a chemical process that takes place in the cytoplasm and mitochondria of cells.

Cells like muscle cells have lots of mitochondria.

This is because they require more energy to do the work they need to do.

Aerobic cellular respiration can be summarised as oxygen plus glucose reacts to make carbon dioxide plus water.

Good work everyone.

Really fantastic effort on all your hard work today.

Take a break now and I'll see you again soon for our next lesson.