Lesson video

Welcome to this lesson from the Oak National Academy.

Today's lesson is all about anaerobic cellular respiration in humans.

We've talked a lot about cellular respiration, and now we're gonna introduce a new form of respiration, anaerobic respiration.

This type of respiration is different depending on what organism it occurs in.

So today's lesson is just about how it happens in human beings.

Hi there, I'm Mrs. Wheat and I'll be taking you through today's lesson.

By the end of today's lesson, you'll be able to describe the differences between aerobic and anaerobic cellular respiration in humans.

Let's have a look at our keywords.

So we have four keywords for today's lesson.

Let's go through them.

First we've got aerobic cellular respiration, anaerobic cellular respiration, lactic acid, and cytoplasm.

Okay, so let's look at our definitions.

I'm going to show you the definitions for our keywords.

Don't worry about trying to memorise these now.

I'll explain each one of these in tonnes of details when it comes up during the lesson, but if it helps you, you can pause the video now, read them through, or even copy them down into your exercise book so it's easier for you to refer back to them.

So here they are.

Today's lesson is in two parts.

First of all, we'll talk about aerobic and anaerobic respiration in humans.

We'll look at the process in a tonne of details, and then once you're comfortable with that, we'll move on to comparing these two processes.

But first of all, aerobic and anaerobic cellular respiration in humans.

A chemical process called cellular respiration takes place in our cells to provide the energy we need for life processes.

I want you to have a little think now, can you think of any life processes that require energy, anything that happens in our bodies that requires energy? I'll give you five seconds to think about your answer, but you might wanna pause the video to give yourself a bit of extra time.

Then press play again when you're ready.

What did you come up with? There's so many different things our bodies do that you could have mentioned.

You could have talked about some parts of digestion, you've talked about active transport or how we build molecules that we need from smaller molecules in order to survive.

We're gonna talk about one key process now, we're talking about muscle contraction.

Muscle contraction is a life process that requires energy from cellular respiration.

We've got three main types of muscle contraction we'll talk about.

We'll talk about the muscle contraction that makes our heart beat, the muscle contraction that moves food through our digestive system and the type of muscle contraction that moves our bones.

So that last one tends to be the one that we think about all the time when we think about muscles.

But muscles don't just move our skeleton.

They do other things on our body as well.

So that's our skeletal muscle, but we also have cardiac muscle and smooth muscle that have really important roles in our body too.

Aerobic cellular respiration is a form of respiration that occurs in cells when they have plenty of oxygen.

So right now I'm sitting down, I'm reading, I'm thinking, but I'm not doing tonnes of strenuous activity.

So my cells are doing aerobic cellular respiration.

I can get enough oxygen for all of them in order for them to do that.

The reactants and products of aerobic cellular respiration are glucose plus oxygen reacts to make carbon dioxide plus water.

So glucose and oxygen are reactants.

Carbon dioxide and water, those are our products.

Aerobic cellular respiration takes place in the cytoplasm and mitochondria in our cells.

So here we have a muscle cell and those are little kidney bean shaped things.

Those in the mitochondria.

And then we've got this jelly-like substance that all the other parts of cell is suspended in.

That's a cytoplasm.

The oxygen that is needed for cellular respiration comes from the air we breathe in.

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

Oxygen from the air in the lungs is transported to every cell in the body by the blood.

Let's see if we understood that.

Which statements explain why muscle cells have a lot of mitochondria, is it A, they are animal cells, is it B, the mitochondria are needed for aerobic cellular respiration, is it C, the mitochondria make food for the cells, or is it D, cellular respiration provides energy for muscle contraction? So you've got five seconds to think about it, but if you wanna pause the video to give yourself a bit of extra time, that's totally fine.

Click play when you're ready to hear the answers.

Let's go through the answers.

So is it A, they are animal cells? It is not I'm afraid.

Sorry if you thought it was that one.

Some animal cells have lots of mitochondria, but others don't, so it's not that one.

Is it B, the mitochondria are needed for aerobic cellular respiration? Yes, it is, mitochondria are an important site of aerobic cellular respiration along with the cytoplasm.

So that's why muscle cells have lots of mitochondria.

Okay, is it C, the mitochondria make food for the cells? No, it is not, I'm afraid again, sorry if you thought it was that one.

You're getting a bit confused there I think with photosynthesis, mitochondria don't make food.

They use glucose as a fuel to release energy.

That's cellular respiration.

Okay, is it D, cellular respiration provides energy for muscle contraction? Yes, it is, well done if you've got both of those correct.

Our muscle cells work hard when we exercise.

So we look at those pictures, we've got people playing basketball, we've got someone swimming, we've got someone racing, that requires tonnes and tonnes of energy.

Right now I'm just sitting.

So as I said before, all of my cells are getting all the oxygen they need in order for aerobic respiration to happen.

Sometimes our muscles need to work a bit harder than that.

The mitochondria and the contracting muscle cells need a lot of oxygen for cellular respiration.

Sometimes oxygen cannot be transported to the muscle cells fast enough.

So what happens then? So anaerobic cellular respiration takes place when there is no oxygen available for aerobic cellular respiration.

So if I started doing exercise right now, if I started doing really strenuous exercise and I don't know, lifting weights, sprinting, then I wouldn't be able to breathe fast enough in order to get the oxygen I need for all my cells.

I'd start doing anaerobic cellular respiration instead.

We look at these two words, they've got lots in common, and the part I wanna focus on is that aero part.

Do you remember what that means? Take five seconds or pause the video, have a think.

What does aero mean? It means air.

So that is to do with the fact that we need oxygen from the air in order for aerobic respiration to happen.

So anaerobic respiration, what does that, those two letters, what does that mean, A-N, an? That's adding meaning to our word, what does it mean? It means without.

So that whole word means without air.

So hopefully that will help you remember that anaerobic respiration is the type of respiration that occurs when there's not oxygen available.

Okay, let's check our understanding of that.

True or false, anaerobic respiration takes place when oxygen is not available, is that true or is that false? Take five seconds or pause the video to think about your answer.

It's true, okay, let's justify that answer though.

Why is it true? Is it true because I know this because anaerobic means without oxygen or B, I know this because respiration means without oxygen? Take five seconds or pause the video to think about your answer.

It is A, great work if you got that right.

The an, the A-N part of anaerobic, that means without, the aero part of anaerobic, that means air.

So altogether it's without air or without oxygen from the air.

Well done if you got that right.

Let's look at the word summary for anaerobic cellular respiration.

But actually before we do that, I wanna put a little note about respiration equations and (indistinct) equation in general.

So as you hopefully know, respiration is a multi-stage process.

It's not as simple as one reactant turning into one product or a few reactants turning into a few products.

There's tonnes and tonnes of different individual steps, and what these word equations are, they're not really technically word equations.

They're summaries, even though I will call them word equations, but what they do is they summarise the whole process with the inputs and the outputs.

Our input is glucose, our output is something we'll talk about in a sec.

So they're summarising a huge amount of information.

They're really, really useful for our science education right now, okay? But if you wanna know the full story, I highly encourage you to study biology in Post 16 education.

So have that in the back of your mind as we talk about this equation.

So the word summary for anaerobic cellular respiration in humans is glucose, the reactant reacts to make lactic acid.

So glucose is the only reactant that's different from aerobic respiration where oxygen is also reacting.

And lactic acid is the only product of anaerobic cellular respiration in humans.

So I've already kind of teased there are different types of anaerobic cellular respiration.

Today's just about how it happens in humans.

I'm sure we can all relate to this situation.

Sometimes when we exercise, we can get muscle cramps.

So the reason for that is that it's caused by a buildup of lactic acid in our muscle tissue.

This is because anaerobic cellular respiration has taken place 'cause there was not enough oxygen reaching the cells for aerobic cellular respiration to take place.

The lactic acid produced during anaerobic cellular respiration is a waste product.

It is transported to the liver by the blood.

The lactic acid is broken down in the liver to remove it from the body.

So in anaerobic cellular respiration, glucose is broken down incompletely.

It's broken down to a thing called lactic acid.

Our bodies don't like it very much.

It doesn't like it being there.

And so eventually when we stop exercising, we need to kind of get rid of it so it gets taken to the liver and broken down, and then we excrete it, remove it from our bodies.

Let's see if we understood that.

Fill in the gaps to complete the word equations for aerobic and anaerobic cellular respiration in humans.

Use some of the keywords from the list.

Oxygen, glucose, carbon dioxide, lactic acid and water.

Take five seconds or pause the video if you need a bit more time to think about your answer.

Let's look at our answers.

So aerobic cellular respiration.

Our reactants are glucose and oxygen and our products are carbon dioxide and water.

Anaerobic cellular respiration in humans, our reactants are just glucose, our products, just lactic acid.

Great work if you got that right.

Let's have a go at our first practise task for today's lesson.

So here we have James, James is playing football.

James is warming up in a PE lesson.

At first he feels fine.

He and the rest of his class are jogging around the pitch.

The next exercise is to do sprint training to improve their speed during football matches.

James quickly gets a cra.

Oh, James quickly gets a cramp in his calf.

I didn't think that was a tongue twister, turns out it is.

Explain in terms of cellular respiration why James felt fine whilst he was jogging, but got on muscle cramp when he started sprinting.

So you'll need to pause video here to give yourself a few minutes to have a go at writing your answer.

Click play when you're ready to see the answer.

Good luck, everyone.

Let's see how you did.

At first, James feels fine because he is able to take in enough oxygen by breathing in air for aerobic cellular respiration to take place.

When they start sprinting, he can't take in oxygen fast enough for his muscles to aerobically respire.

His muscles carry out anaerobic cellular respiration instead, lactic acid is made during anaerobic cellular respiration and causes muscle cramps.

Great work with your first practise task, having a go at everything we learned in that first part of the lesson.

So we've had a look at the word summaries for aerobic and anaerobic cellular respiration in humans.

Now we're gonna have a go at comparing aerobic and anaerobic respiration in humans.

So when you see the word compare, you should already be thinking, okay, that's to do with similarities and differences.

Let's have a look at some of the similarities and differences between aerobic and anaerobic respiration in humans.

So they are both chemical reactions, which use glucose as a fuel to provide energy for life processes.

Let's have a look at the word summaries and compare those.

Reactants for aerobic respiration, we've got glucose and oxygen, products, we've got carbon dioxide and water.

For anaerobic respiration, we have just glucose, so again, that glucose they have in common, but oxygen is not a reactant in anaerobic respiration.

So that's a big difference.

Products, products are completely different.

There's only one and it's lactic acid.

So one difference between the two processes is that anaerobic cellular respiration is a shorter process that provides energy more quickly, which is really useful.

When we're doing anaerobic cellular respiration, we're exercising, we're doing something strenuous like that.

So we do need energy fast.

However, it provides less energy for life processes than aerobic cellular respiration.

So anaerobic respiration is a shorter process, provides energy super fast, but it provides less energy overall.

So that's a bit of a downside.

We can't do anaerobic cellular respiration indefinitely, it provides way less energy.

Let's check to see if you understood that.

Which of the following statements are true, A, anaerobic respiration provides energy more slowly than aerobic respiration, anaerobic respiration provides less energy than aerobic respiration, anaerobic respiration provides more energy than aerobic respiration, anaerobic respiration provides energy more quickly than aerobic respiration? Take five seconds or pause the video.

Come back when you're ready to hear the answer.

Okay, let's look at the answers.

B, anaerobic respiration provides less energy than aerobic respiration and D, anaerobic respiration provides energy more quickly than aerobic respiration.

Great work if you've got those.

Another difference between the two processes is the location where they occur inside cells.

Aerobic respiration takes place in the cytoplasm and partly in the mitochondria.

Anaerobic respiration takes place only in the cytoplasm.

Let's see how you're doing.

Where does anaerobic cellular respiration take place in the cell? Take five seconds or pause the video.

Click play when you're ready to hear the answer.

Okay, let's have a look at the answers.

So is it A, A is pointing to a mitochondrion, which is the site of aerobic cellular respiration, but not a site for anaerobic cellular respiration? Could it be B, what was B? B is a nucleus, which is where DNA is stored in the cell.

So it's not that.

Could it be C? C is the cell membrane.

That's what controls what goes in and outta the cell.

So it's not that either.

What about D? Well, D is a ribosome where protein is made in the cell.

So it's not that.

So it must be E, the cytoplasm, which is this jelly-like liquid, which all of the other organelles or subcellular structures are suspended in within the cell.

And cytoplasm is where a lot of chemical actions like anaerobic cellular respiration happens in the cell.

Well done if you got that right.

Okay, this is our final practise task for today's lesson.

Great work for getting here.

You've done really, really well so far.

Okay, so placed each statement into the correct section of a Venn diagram to show whether it refers to aerobic respiration, anaerobic respiration, or both.

So remember a Venn diagram, we've got those two circles.

The overlapping section is where the both statements go.

And then either other section is either for anaerobic respiration or aerobic respiration.

So statements are produces lactic acid, oxygen is a reactant, provides a lot of energy for life processors, provides less energy for life processes, happens in mitochondria, happens in cytoplasm, glucose is a reactant, it's a series of chemical reactions, carbon dioxide and water are produced, provides energy for life processes, provides energy faster, can cause muscle cramps.

So remember, you need to put those in the correct section of the Venn diagram.

You are gonna need to pause video now for a few minutes so that you can have a chance to do that task.

Click play when you're ready to see the answers.

Okay, let's look at the answers.

So produces lactic acid, where does that go? That is anaerobic respiration.

Oxygen is a reactant, where does that go? Aerobic respiration.

Provides a lot of energy for life process.

That's aerobic respiration.

Provides less energy for life processes, anaerobic respiration.

Happens in mitochondria, aerobic respiration.

Happens in cytoplasm, that is both processes.

Glucose is a reactant, that is also both processes.

It's a series of chemical reactions.

Again, that's both.

Provides energy faster, that's anaerobic respiration.

Carbon dioxide and water are produced, that's aerobic respiration.

Provides energy for life processes, that's both.

Can cause muscle cramps, anaerobic respiration.

Really, really great work.

That's our task that's summarising comparing aerobic and anaerobic respiration.

If you got that right, feel super proud of yourself.

Great work on today's lesson.

Let's summarise it to help it stick in our minds.

The word summary for anaerobic cellular respiration in humans is glucose reacts to make lactic acid.

The word summary for aerobic cellular respiration in humans is glucose plus oxygen reacts to make carbon dioxide and water.

So let's look at our table, cellular respiration in humans.

So our key points for aerobic respiration, oxygen is the only reactant, provides more energy, it's a slower chemical process and it takes place in the cytoplasm and the mitochondria.

Let's look at our summary for anaerobic respiration.

Oxygen is not a reactant, provides less energy.

It's a faster chemical process.

It takes place in the cytoplasm only, and lactic acid, the product of anaerobic respiration, can cause muscle cramps.

It's been great working with you today.

Well done on all your amazing effort.

Have a break now and I'll see you back really soon for our next lesson.