Lesson video

<v Instructor>Hello and welcome to this lesson from the Oak National Academy.

Today's lesson is all about breathing, respiration, and gas exchange, and it's the first lesson in the unit all about "Breathing and respiration." I wonder what connections your brain is already making with those keywords.

I'm sure you've heard of breathing, maybe you've heard of respiration, and a small number of you might have heard of gas exchange, but what are they? How are they different? How do they work? Are they different? That's what this lesson is all about.

I'm Mrs. Wi.

At the end of today's lesson, you'll be able to describe the differences between breathing, respiration and gas exchange.

Now don't worry if you thought those were all the same things.

It's really, really common to get them confused.

We're gonna spend plenty of time talking about what they achieve, where they happen, and all those sorts of things, and that's gonna support your understanding about this topic.

Let's have a look at our keywords.

So we have breathing, lungs, cellular respiration.

I want to pause and look at that word in more detail.

Cellular respiration is more commonly known as just respiration, but I think it's more helpful to kind of use its full name, cellular respiration, because it gives us some more information about the process and it helps us tell the difference between respiration and breathing.

Breathing happens in the lungs, which are an organ, but for some reason, it's really common for people to get the words breathing and respiration confused.

So if we kind of always remember breathing happens in the lungs, respiration happens in cells, that helps our brain remember these things are different.

So that's why I call it cellular respiration.

But if you see it written as just respiration, they are the same thing.

Okay, let's keep going.

Mitochondria, gas exchange.

Those are our keywords for today.

Let's look at the definitions.

Before we go through these, I just wanna mention that I don't want you to try and memorise all of these right now.

I want you to be familiar with them and hopefully, it will jog your memories.

But every time each of these keywords comes up in the lesson I will re-explain it again.

So please don't feel pressured to, "Oh my gosh, I have to cram all of this into my brain." We'll go through it.

Okay, so breathing is the process in which air moves in and out of the lungs.

The lungs are a pair of organs found in humans and some other animals.

Cellular respiration is a chemical process in cells, which uses sugar as a fuel to provide energy for life processes.

Subcellular structures called mitochondria use sugar and oxygen for cellular respiration.

The process of oxygen diffusing from the lungs into the blood, and carbon dioxide diffusing from the blood to the lungs is known as gas exchange.

So maybe, you knew some of that already, maybe that is all completely new to you.

Again, please don't stress.

Don't worry about trying to cram it all in your brain.

Every time each one of these words comes up in the lesson, we'll look at it in its context and redefine it again.

Today's lesson is in two parts.

The first part is all about breathing and respiration, what they are and how they're different.

We're gonna spend lots of time looking at those two keywords.

Then once we're comfortable with that, we'll talk about gas exchange and do exactly the same thing.

But first, let's get started with breathing and respiration.

Well think about breathing first.

That's probably the one that you're most familiar with.

Humans can't stay underwater for too long, but why is that? Pause the video and have a think or a chat with the person next to you about why humans can't stay underwater for very long.

What did you come up with? The reason humans can't stay underwater indefinitely is 'cause we need air to breathe.

There isn't any air that we can access underwater, so we need to come up to the surface to breathe air.

Some other animals like dolphins or turtles are better at holding their breath, but they still need to come to the surface every once in a while to breathe air.

Why is that? Why is breathing so important? Breathing is a process in which air is moved in and out of the lungs.

Look at my arrow, that's showing the air move into the mouth and nose through a series of tubes, which we'll talk about in detail in the next lesson, and then down into our lungs.

That's the process of breathing.

So breathing is about moving air in and out of these organs called the lungs.

But why is air so important? What do you already know about air? Pause the video now and have a think about that question.

Air is a mixture of different gases.

This pie chart is gonna show us the proportion of gases that are in the air.

Let's start with the most abundant gas in the atmosphere, the white section of my pie chart.

What gas do you think that is? Have a little think about that.

It's nitrogen, which surprises a lot of people.

Some people think that should be oxygen, but most of the air is actually made up of a really unreactive gas called nitrogen that isn't involved with the process of breathing, respiration or gas exchange at all.

What about the next most abundant gas, the red section? What do you think that is? That one is oxygen.

Well done.

What we have left over are some gases that are present in the air in really small amounts.

Carbon dioxide takes up less than 1% of the air, and then we have a mixture of other gases like argon or methane, which also take up less than 1% of the air.

So which parts of the air do you think are the most important for breathing and respiration? Pause the video and have a think.

It's oxygen.

Humans and other animals need oxygen from the air to keep their cells alive.

Let's check our understanding of that.

True or false, our body needs all of the gases in the air to keep our cells alive.

Is that true or is that false? Pause the video so you can have a think about your answer.

It is false.

Okay, but why is it false? Let's try and justify the answer to that question.

So is it false because A, cells only need oxygen to stay alive, or B, cells only need carbon dioxide to stay alive? Pause the video and have another think.

It is A, cells only need oxygen to stay alive.

Good job if you got that right.

So when we breathe, air enters our lungs.

Here are our lungs.

They are a pair of organs in our chest.

The oxygen from our breath is absorbed into our blood and transported through blood vessels to cells all over our body.

Here we have the blood vessels.

They go everywhere in our body bringing the oxygen from our breath to the cells that need them.

So we've looked at breathing and now we're gonna look at how oxygen is involved in respiration.

What do you think this might be then? Have a think back to previous science lessons.

What might this be? Pause and think about that.

It's a cell.

We are made up of trillions of cells, which all need oxygen to function.

Body cells contain structures called mitochondria that use oxygen for cellular respiration.

Here in the mitochondria, you can see that they're smaller than a cell.

They're inside a cell in fact.

Cellular respiration in mitochondria is a chemical process.

It uses oxygen and sugar from food as fuel to provide energy for life processes.

So that's how breathing and respiration are connected.

Breathing in provides ourselves with the oxygen they need to carry out cellular respiration.

Let's recap what we've learned about breathing and respiration so far.

Breathing and cellular respiration are different processes.

They're linked, they're related to each other, but they are different things.

They happen in different places and they achieve different things.

During breathing, air is moved in and out of the lungs.

So where does breathing happen? It happens in the lungs.

What does breathing achieve? It's about moving air in and out of the body.

Respiration.

During respiration, the mitochondria in cells combine oxygen with sugar to provide energy.

So where does respiration happen? It happens in our cells.

It happens in every single cell in our whole body.

What does respiration achieve? It's all about providing energy.

Hopefully you're starting to see why these two processes are different.

Let's check our understanding.

Complete the sentences about cellular respiration.

Use the words from the list.

Energy, mitochondria, oxygen, sugar.

Pause the video and have a think about those questions.

Let's go through our answers.

During respiration, oxygen from the air and sugar from food are used to provide energy for life processes.

This takes place in cell structures called mitochondria.

Well done if you've got that right.

We've already said oxygen diffuses into mitochondria for cellular respiration.

But there's another gas that's involved in cellular respiration, which we're gonna look at now.

Let's make the mitochondria a bit bigger though.

Okay, so that's the oxygen diffusing into the mitochondria.

Now the other gas that's involved is carbon dioxide.

Carbon dioxide is produced during cellular respiration and diffuses out of the mitochondria.

The carbon dioxide produced during cellular respiration is a waste product.

It's transported back to the lungs by the blood.

It's then breathed out.

So this is another gas that links the processes of respiration and oxygen.

It's made during cellular respiration and we remove it from our bodies by breathing out.

Let's see if we've understood that.

Put these statements about breathing and respiration in the correct order.

The first one's been done for you.

So number one, air is breathed into the lungs.

Then we've got carbon dioxide is transported by the blood back to the lungs.

The blood takes oxygen to all the cells in the body.

Oxygen from the air in the lungs moves into the blood.

Carbon dioxide is produced during cellular respiration.

The oxygen is used by cells for cellular respiration.

So put those remaining sentences into order.

Pause the video while you have a think about the correct order those sentences should go in.

Let's check our answers and see how you did.

So the first one was already done for you.

Air is breathed into the lungs.

Then we have oxygen from the air in the lungs moves into the bloods.

The next one should be the blood takes oxygen to all the cells in the body.

Then we've got the oxygen is used by the cells for cellular respiration.

Carbon dioxide is produced during cellular respiration.

Carbon dioxide is transported by the blood back to the lungs.

Really good job if you've got that right.

Here's that pie chart again.

Remember, it's showing us the proportion of gases in the air we breathe in.

This next pie chart is showing us the proportion of gases in the air we breathe out.

So you should be able to see there's some differences between these.

What are they and why are they different? Pause the video and think about that.

So one of the differences is, is there is less oxygen in the air we breathe out.

Why is that? It's because some of the oxygen in our breath has been used for cellular respiration.

What about the carbon dioxide? So there's more carbon dioxide in the air we breathe out, and that's because our cells make carbon dioxide during respiration and we remove it from our bodies by breathing out.

Well done if you've got some of that.

Now let's check our understanding.

How do the gases in the air we breathe out compare to the the air we breathe in? Is it A, the amount of oxygen has decreased.

B, the amount of carbon dioxide has increased.

C, the amount of oxygen has decreased and the amount of carbon dioxide has increased.

Or D, the gases are present in exactly the same amounts? Pause the video.

What do you think about that question? It is C, the amount of oxygen has decreased.

The amount of carbon dioxide has increased.

Remember, the oxygen has decreased because that oxygen was used in cellular respiration.

The carbon dioxide has increased because that's a product of respiration.

Good job if you've got that.

Here is our first practise task for today's lesson.

Candles need oxygen to burn.

A student places burning candles inside two jars of air.

So in jar A, we've got air from the room.

In jar B, we've got air breathed out by a person.

Already have a think, how might the gases in air from the room, jar A, be different from jar B, air breathed out by a person.

What's changed in the gases there? So question one, predict what will happen to the candle in each jar.

Question two, explain why you think this will happen.

And it's all about the gases inside those jars.

Pause the video now for a few minutes while you write down your answer.

Let's see how you did.

Predict what will happen to the candle in each jar.

At first, both candles will burn.

The candle inside jar B containing air breathed out by a person will go out first.

Then the candle inside jar A containing air from the room will go out.

Explain why you think this will happen.

At first, both candles will burn because both jars contain some oxygen.

The candle inside jar B will go out first because there's less oxygen and more carbon dioxide in air breathed out by a person.

This is because some of the oxygen is used for cellular respiration in the person's cells.

The extra carbon dioxide was produced by cellular respiration and breathed out.

Both candles eventually go out when all the oxygen in the jars is used up, has been combusted.

How did you guys do? Well done on the first practise task for today's lesson.

We've looked at breathing and respiration now we're gonna look at gas exchange.

Gas exchange is a process that happens between breathing and cellular respiration.

It links those processes together.

Which gases might be being exchanged here? Pause the video and have a think about that.

That's right, it's carbon dioxide and oxygen again, and they are switching or changing places.

That's what gas exchange is about.

Gas exchange moves oxygen and carbon dioxide between the air and the blood.

We're going to look at gas exchange in detail now.

We're starting with the air we breathe in.

Air containing particles of oxygen and carbon dioxide are breathed in.

Let's zoom in on a part of the lungs and see what's going on.

This structure here is an air sac.

We're gonna go into lots of detail about this in a future lesson, but for now, just know that it's a tiny part of the lungs.

So air fills tiny air sacs in the lungs.

Each sac is surrounded by blood vessels.

So this tiny part of the lung is called an air sac and the blood vessel surrounding it is where gas exchange takes place.

The gases are being exchanged between this air sac and the blood vessel.

We're gonna look at what oxygen is doing during gas exchange first.

Particles of oxygen from the air sac diffuse into the blood.

The oxygen is transported around the body by the blood.

Oxygen from the blood diffuses into cells and is used for cellular respiration.

So the oxygen is starting inside the air sac diffusing into a blood vessel that goes all around the body, takes the oxygen to cells, and the oxygen is then used there for cellular respiration.

Let's see if we understood that.

Complete these sentences about gas exchange.

Pause the video now whilst you have a go at these sentences.

Let's see how you did.

When we breathe in, air moves into our air sacs in our lungs.

Oxygen diffuses from the air sacs into our blood.

This is then transported to cells all around our body where it is used for cellular respiration.

How did you find that? Now we're gonna look at what carbon dioxide is doing during gas exchange.

Carbon dioxide is formed in the mitochondria of cells during cellular respiration.

The carbon dioxide diffuses out of the cells and into the blood.

This carbon dioxide is brought back to the air sacs in the lungs by the blood.

The carbon dioxide diffuses into the air sacs and is breathed out by the lungs.

Okay, carbon dioxide is made in cells during cellular respiration, goes into the blood vessels, diffuses back into the air sacs, and then we breathe it out.

And that's everything.

That's all the new content for today's lesson.

Really, really good job, guys.

Let's now check our understanding and practise that.

Complete the sentences about gas exchange.

Use some of the words from the list below.

Lower, blood, oxygen, carbon dioxide, higher, lungs.

Pause the video now while you complete those sentences.

Let's check our answers.

During cellular respiration, cells make carbon dioxide.

This diffuses from the cells into our blood and then into an air sac in the lungs.

We breathe out air that has a higher concentration of carbon dioxide and a lower concentration of oxygen.

How did you find that? Okay, this next task, we are matching the keywords to their definitions.

Pause the video while you match those keywords.

Let's check our answers.

Respiration, a chemical process in the mitochondria of the cells that provides energy for life processes.

Breathing, the process in which air is moved in and out of the lungs.

Gas exchange, the process of oxygen diffusing from the lungs into the blood and carbon dioxide diffusing from the blood into the lungs.

Great job if you got that one right.

That is the point of today's lesson.

Being able to tell the differences between those processes.

Let's keep practising.

This is our final practise task for today's lesson.

Who is right and who is wrong? Explain your answers.

So Alex thinks breathing and respiration are the same thing, Andeep thinks Alex is wrong.

Breathing involves the lungs, and respiration happens in cells, so they're different.

Izzy thinks it's gas exchange and respiration that are the same thing.

Who is right, who is wrong? Remember to explain your answers.

Pause the video now for a few minutes whilst you write the answer to your question.

Let's check our answers.

Alex and Izzy are wrong, Andeep is right.

Respiration, breathing and gas exchange are all different processes.

Breathing happens in the lungs, respiration happens in cells, and gas exchange occurs between air sacs and blood vessels.

Well done on that.

Let's sum up what we've learned today.

Breathing is the process in which air is moved in and out of the lungs.

Cellular respiration is a chemical process in the cells which uses sugar as a fuel to provide energy for life processes.

During respiration, mitochondria in cells combine oxygen with sugar to provide energy.

The process of oxygen diffusing from the lungs into the blood and carbon dioxide diffusing from the blood to the lungs is called gas exchange.

The air we breathe out contains more carbon dioxide and less oxygen than the air we breathe in.

This is because our cells have used some of the oxygen and produced carbon oxide as a waste product during the process of cellular respiration.

Incredible work today, learning all those new key terms and processes.

Go take a well-deserved break, and I'll see you back here for our next lesson.