Topic Three (1.3): Respiration

Topics Icon.png Objectives

By the end of this topic, you should be able to:

  • explain how the body responds to increased demands for energy during exercise.

Revision Tasks Icon.png Retrieval starter questions

What type of tissue would contain sieve plates? What is the function of a sieve plate?

Introduction Icon.png Introduction

In this topic, you will learn how the body makes energy and what happens during exercise. The body constantly needs energy to carry out many processes; you even need energy in your sleep! Respiration is the process of energy production and takes place in the mitochondria of cells. You will have learnt about respiration in previous modules. You may wish to spend time reactivating your knowledge of respiration.

A common misconception is the difference between respiration and respiratory systems.

  • Respiration is the chemical reaction that takes place in all living cells to release energy from glucose.
  • The respiratory system is the organs involved in gas exchange.

Interact Icon.png Working through your course book

Reactivate activity - optional

Before applying your knowledge to new concepts in this topic, you can check your understanding of previous concepts. If you want to check your understanding and reactivate your knowledge, please complete this reactivate activity:

Watch the Revision Monkey video to revise aerobic respiration:

  • Read ‘Aerobic Respiration’ on page 21 in your Activate 3 coursebook and answer the Reactivate your knowledge questions at the top of page 26.

Apply your knowledge

You are now ready to apply your knowledge of respiration and extend your learning.

Aerobic respiration uses oxygen and glucose. Oxygen from the air enters our lungs and is transported in the blood to the mitochondria in the cells. Glucose also reaches the mitochondria from the food that we eat. Energy is produced and during the reaction there are some waste products: carbon dioxide and water.

Remember: aerobic respiration takes place in plants too.

  • Read pages 26-27 in your Activate 3 coursebook.
  • Write out the word equation for aerobic respiration.
  • Use Figure 1 at the bottom of page 26 to summarise how glucose and oxygen get into cells.

During exercise, muscles need more energy. They need to respire at a faster rate, so they need more oxygen and glucose. Our breathing rate increases to increase the supply of oxygen. More carbon dioxide is also produced and needs to be removed at a faster rate. Watch this video to see what happens during exercise:

  • Why does the heart beat faster during exercise?
  • Optional activity - you can complete the respiration practical below to find out what happens to the breathing rate during exercise. You can take part yourself, with the help of an observer/friend or family member, or somebody else can do the activity to obtain the results. Note: please make sure, before you begin, that anyone who is doing the activity (yourself included) is not unwell. Use the support sheet to record your results. If you need to reactivate your knowledge of line graphs, read page 13 of your Activate 3 coursebook.

COMPLETE - B3 1.4 Practical: Respiration Instructions (Kerboodle) [Not available on sample course]

COMPLETE- B3 1.4 Support: Respiration Worksheet (Kerboodle) [Not available on sample course]

  • Complete Summary questions 1-6. 
  • Maggots carry out aerobic respiration. Watch this video, which demonstrates how their respiration rate can be measured: 

WATCH - Aerobic respiration in maggots experiment (Twig) [Not available on sample course]

  • Why did the water rise up the tube? 
  • What gas do maggots use? What gas do maggots produce?

Stretch Icon.png Extension activities for this topic

Respiration can take place when oxygen is not present. This is called anaerobic respiration. Humans can respire anaerobically, but only a small amount of energy is produced and the waste products are different. Watch the Revision Monkey video below about anaerobic respiration in animals and yeast.

  • Write the word equation for anaerobic respiration in humans.
  • Write the word equation for anaerobic respiration in yeast.
  • Think about how this differs from aerobic respiration.

Download Icon.png Check your answers

CHECK - Topic question answers - Module One (Kerboodle) [Not available on sample course]

CHECK - Student Book Answers – B3 Chapter 1 (Kerboodle) [Not available on sample course]