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Describe the Process of Anaerobic Respiration

Worksheet Overview

QUESTION 1 of 10

Did you know that Usain Bolt is currently the fastest sprinter in the world? He ran 100 metres in a record 9.58 seconds!

 

Image of athletes running

 

In order to do this, Usain Bolt’s muscles need to respire super quick. He needs all that energy to sprint so fast. But his body can’t keep up with these demands - it can’t respire fast enough. This is where anaerobic respiration steps in. 

 

Image of females exercising

 

 

Anaerobic respiration is where glucose breaks down but without oxygen. Energy is released, but not as much as in aerobic respiration. Lactic acid is produced instead of carbon dioxide and water. Lactic acid can cause painful cramps - something we feel in our muscles that stops us from carrying on. To get rid of the lactic acid, the person must breathe in deeply in order to get a good supply of oxygen. You have to keep breathing hard for a while after you stop exercising in order to get oxygen into your muscles. This will convert the painful lactic acid which has built up into harmless carbon dioxide and water. The amount of oxygen needed to do this is called the oxygen debt.

Anaerobic respiration can be represented by the word and symbol equation: 

 

glucose → lactic acid 

C6H120 → 2C3H6O3

 

The reactant in anaerobic respiration is glucose. The product is lactic acid. A small amount of energy is also released.

Anaerobic respiration occurs in the cytoplasm of the cell rather than the mitochondria, as in aerobic respiration. 

Plants can also respire anaerobically. However, they don't produce lactic acid. Glucose is broken down into ethanol and carbon dioxide.

 

Image of plant and animal cell

 

Uses of anaerobic respiration

 

Image of alcohol

 

 

Yeast is a fungus that can respire anaerobically. It has many uses - the most common use is in bread making and alcohol brewing. Yeast will respire anaerobically, releasing alcohol and carbon dioxide. The carbon dioxide helps bread to rise, giving it its fluffy texture. This process is also known as fermentation.

 

glucose → alcohol + carbon dioxide

 

C6H12O → 2C2H5OH + 2CO2

 

Image of bread made with yeast

 

In the following activity, you will describe the process and uses of anaerobic respiration.

What is the name of X and Y in the equation below?

 

Image of anaerobic respiration equation

Some plants and microorganisms respire anaerobically.

 

Where can anaerobic respiration be used in industry?

Making paper

Making wine and beer

Making chocolate

Making bread

Fill in the blanks below describing anaerobic respiration.  

Making paper

Making wine and beer

Making chocolate

Making bread

 

Yeast respires anaerobically and is used to make beer.

 

Complete the word equation for the reaction that takes place: 


 

...A... → alcohol + ...B...

Column A

Column B

A
Carbon dioxide
B
Glucose

Lizzie is making bread. She adds yeast to her flour and other ingredients before placing it in the oven. Lizzie's bread rises nicely. 

 

How did the bread rise? 

 

Image of bread

Column A

Column B

The yeast respires anaerobically
releasing carbon dioxide
The carbon dioxide gets trapped
in the dough causing it to rise

Adding yeast to grapes that anaerobically respire, makes wine.

 

Why does the yeast need grapes to be able to respire?

 

Image of alcohol

The grapes are a source of energy

The grapes are a source of glucose needed for respiration

The grapes taste nice

 

When athletes train hard they can respire anaerobically. 

 

Which of the following statements about anaerobic respiration is true?

Lactic acid and carbon dioxide are produced

Lactic acid can build up, causing cramp

Water and carbon dioxide are produced

What is meant by the term oxygen debt? 

The amount of oxygen needed to break up glucose into carbon dioxide and water

The amount of oxygen needed to break up lactic acid into carbon dioxide and water

The amount of oxygen needed to break up lactic acid into energy

What are two differences between anaerobic and aerobic respiration? 

 

Note that ATP is the name for the molecule in cells that carries energy.

 

 1

  ATP is released in both anaerobic and aerobic respiration

 2

 Less ATP is released in anaerobic respiration than in aerobic respiration

 3

 Carbon dioxide isn't produced in anaerobic respiration but is in aerobic respiration

 4

 Glucose is a reactant in aerobic and anaerobic respiration

1 and 4

2 and 3

3 and 4

Plants, like animals, can respire anaerobically.

 

Describe how plants and animals differ when they respire anaerobically.

1 and 4

2 and 3

3 and 4

  • Question 1

What is the name of X and Y in the equation below?

 

Image of anaerobic respiration equation

CORRECT ANSWER
EDDIE SAYS
How did you get on with this first question? This equation is a very important one to know, so take some time to learn it if you weren't too sure. There is only one reactant (glucose) and one product (lactic acid) in anaerobic respiration. Carbon dioxide and water are the two products of aerobic respiration.
  • Question 2

Some plants and microorganisms respire anaerobically.

 

Where can anaerobic respiration be used in industry?

CORRECT ANSWER
Making wine and beer
Making bread
EDDIE SAYS
There were two correct options in this question. Just as in plants, yeast respires anaerobically. Bread making and brewing alcohol are the two most common uses of yeast and the products are carbon dioxide and alcohol. This process is known as fermentation.
  • Question 3

Fill in the blanks below describing anaerobic respiration.  

CORRECT ANSWER
EDDIE SAYS
This activity is useful for making revision notes. Have a few tries if you didn't get it correct the first time around.
  • Question 4

 

Yeast respires anaerobically and is used to make beer.

 

Complete the word equation for the reaction that takes place: 


 

...A... → alcohol + ...B...

CORRECT ANSWER

Column A

Column B

A
Glucose
B
Carbon dioxide
EDDIE SAYS
Try not to confuse the anaerobic respiration equation that occurs in the body with the one that occurs in yeast and plants! All types of anaerobic respiration require the same reactant - glucose, but they have different products. In our bodies, the product is lactic acid, but in plants and yeast cells, carbon dioxide is produced as well as ethanol or alcohol.
  • Question 5

Lizzie is making bread. She adds yeast to her flour and other ingredients before placing it in the oven. Lizzie's bread rises nicely. 

 

How did the bread rise? 

 

Image of bread

CORRECT ANSWER

Column A

Column B

The yeast respires anaerobically
releasing carbon dioxide
The carbon dioxide gets trapped
in the dough causing it to rise
EDDIE SAYS
Remember the equation for anaerobic respiration in yeast cells? The products are alcohol or ethanol, plus carbon dioxide. The carbon dioxide here proves to be useful! It helps the bread to rise, keeping it nice and fluffy.
  • Question 6

Adding yeast to grapes that anaerobically respire, makes wine.

 

Why does the yeast need grapes to be able to respire?

 

Image of alcohol

CORRECT ANSWER
The grapes are a source of glucose needed for respiration
EDDIE SAYS
Think back to that all-important equation for anaerobic respiration. Glucose is the reactant needed for anaerobic respiration to occur. Without the grapes, the yeast will have no source of glucose. No glucose, no respiration - aerobic or anaerobic!
  • Question 7

 

When athletes train hard they can respire anaerobically. 

 

Which of the following statements about anaerobic respiration is true?

CORRECT ANSWER
Lactic acid can build up, causing cramp
EDDIE SAYS
Remember that lactic acid is the only product of anaerobic respiration! Lactic acid builds up in muscles causing painful cramps. The athlete would need to stop and breathe fast and deeply to get rid of the lactic acid.
  • Question 8

What is meant by the term oxygen debt? 

CORRECT ANSWER
The amount of oxygen needed to break up lactic acid into carbon dioxide and water
EDDIE SAYS
The term debt means when you owe someone something, normally money! Here, the body owes oxygen, which is why you will have to breathe in quickly and deeply after exercising hard in order to take in as much oxygen as possible. This oxygen will then break up the lactic acid and convert it into carbon dioxide and water.
  • Question 9

What are two differences between anaerobic and aerobic respiration? 

 

Note that ATP is the name for the molecule in cells that carries energy.

 

 1

  ATP is released in both anaerobic and aerobic respiration

 2

 Less ATP is released in anaerobic respiration than in aerobic respiration

 3

 Carbon dioxide isn't produced in anaerobic respiration but is in aerobic respiration

 4

 Glucose is a reactant in aerobic and anaerobic respiration

CORRECT ANSWER
2 and 3
EDDIE SAYS
This is one of those questions that needs to be read carefully to avoid getting it wrong! All the four options are giving correct details about both sorts of respiration. 1 and 4 are similarities between aerobic and anaerobic respiration, since both types of respiration need glucose as a reactant and release energy. We were looking for differences, so the answer was options 2 and 3. More energy is released in aerobic respiration than in anaerobic, and also carbon dioxide is only a product in aerobic respiration.
  • Question 10

Plants, like animals, can respire anaerobically.

 

Describe how plants and animals differ when they respire anaerobically.

CORRECT ANSWER
EDDIE SAYS
The correct sentence should read: Plants produce ethanol (or alcohol) and carbon dioxide when they respire anaerobically, whereas animals produce lactic acid. You could have put either alcohol or ethanol to have got the mark because they are basically the same thing in this instance. Well done for completing this activity!
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