Cellular respiration
Life depends on the transfer of energy. ATP is an important source of energy for biological processes. Energy is transferred from molecules such as glucose, to an intermediate energy source, ATP.
ATP is a reservoir of potential chemical energy and acts as a common intermediate in metabolism, linking energy requiring and energy yielding reactions. Students need to know the structure of ATP, its uses and its role in biological processes.
For core and further science concepts, students will need to understand how substrate molecules such as glucose are broken down in cells to yield energy in the form of ATP, and how this involves both oxidation and reduction reactions. For the occupational area of laboratory science, a more detailed understanding of the biochemical pathways involved in each stage of aerobic respiration is required, including glycolysis, link reaction, Kreb’s cycle and the electron transport chain. Students studying this occupational area will also need to understand the main activities and outputs of beta-oxidation and the role of beta-oxidation in aerobic respiration when an alternative initial substrate such as fat is used.
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or other recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.
ATP and energy (interactive tutorial)
This is a link to an American website which provides a comprehensive discussion on the structure and function of ATP and how it is involved in energy storage and release. The website includes self-assessment quizzes that can be completed as students read through the material to check their understanding. This would be useful for students to study as part of a pre-reading task before a lesson or as part of a consolidation or revision activity. Some of the images and diagrams used would also be useful for reference in a lesson.
The screaming jelly baby
Now regarded as something of a classic demonstration, this procedure vividly illustrates the release of over 100kJ of energy from a sugar-based substrate (a jelly baby). The resource provided here is from the Royal Society of Chemistry and provides a full protocol for the demonstration with a link to the CLEAPSS website for up to date safety considerations. The demonstration is an excellent way of starting a discussion about the process of combustion and comparing the sudden release of energy to the more gradual and sustained release that features in aerobic respiration.
Cellular respiration tutorials
This is a link to an American website which provides a series of interactive tutorials based on each stage of aerobic respiration, from glycolysis through to the electron transport chain. The tutorials include detailed notes, diagrams and quizzes that can be completed as students read through the material. There is also a downloadable student learning guide booklet, videos and instruction on the use of a respirometer. The resources could be used in a variety of ways by both teachers and students, either for pre-reading, revision or for lesson planning.
Cellular respiration
Produced by Wellcome, this poster summarises the main reaction pathways involved with aerobic respiration. This could be used as part of a wall display but could also be used as a teaching or revision tool – students could be tasked with verbally explaining what is happening at each point in the diagram or covering up parts of the diagram and checking their recall of the key facts.
Measuring the rate of metabolism
Practical investigations are essential for students to be able to relate theory to practice and observations. This investigation involves handling whole living organisms and provides a quantitative method of exploring metabolism. Measurements of gas exchange, particularly the rate of uptake of oxygen, give a clear indication of the activity of respiratory metabolism. The equipment used is called a respirometer – not to be confused with a spirometer.
Respiration Changes During Fruit Ripening and Storage
This resource from Science and Plants for Schools provides an original investigation on the changes to respiration during fruit ripening and storage processes. The investigation consists of two protocols, one of which could be altered by students to investigate a range of variables and which involves titration – thereby providing a good cross-over activity that uses chemical techniques in a ‘biology’ investigation. The activity would be of benefit to all students, but particularly those that are focused or interested in food science.
Measuring Respiratory Quotient
Respiratory quotient provides a way of determining the type of respiratory substrate that is being used, based on the volume of carbon dioxide produced and oxygen consumed by an organism. This investigation uses a respirometer to measure volumes of gas production/consumption and allows a respiratory quotient value to be calculated. This links directly to areas of the specification where beta oxidation of alternative substrates are discussed and the investigation provides a good opportunity to develop practical skills. There is a downloadable sheet for this investigation with answers included.
Unfamiliar contexts
Purpose: Some topics are difficult to teach and may benefit from providing additional contexts, so helping students make links between the topic and the wider picture.
Teaching approach: Respiration is a topic that students find challenging. In the past, there has only been a limited range of practical activities available that promote student understanding. Digital technology can provide tools to locate information about a broader range of contexts, and can also provide means by which they can be studied.
Preparation: Students may be asked to investigate respiration by comparing the rate at which different samples of food bring about a colour change in hydrogencarbonate indicator. This could be enhanced by using a web search to find information on respiration rates in vegetables, and linking this to food spoilage. A carbon dioxide gas sensor could then be used to measure rates of carbon dioxide release for a five-minute period from a range of vegetables or fruits.
