Cell metabolism
Processes within cells depend on biological molecules whose structure is related to their function. Inside every cell are reactions that are essential for life. Students need to be able to describe the process of cellular respiration and understand it is continuously occurring in all living cells. Students need to be able to compare the processes of aerobic and anaerobic respiration. Students should appreciate that enzymes are important proteins, essential for reactions to take place. Other biological molecules are also important and students need to be able to explain the importance of sugars, amino acids, fatty acids and glycerol in the synthesis and breakdown of carbohydrates, lipids and proteins.
Students commonly hold the misconception that ventilation is respiration, this misconception is held because of the respiratory system. It is very important therefore to address this at the beginning of teaching this topic through clear definitions of the terms respiration, ventilation and breathing. One approach is to ask students to develop concept maps for each term ( see examples at: http://www.sci-culture.com/advancedpoll/GCSE/differencebetweenbreathinga... ). Another approach is through the use of analogies.
Students also struggle with both the word and symbol equations for respiration and often confuse these with the equation for photosynthesis. Using a sort card activity often helps with this particular difficulty.
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 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.
Screaming Jelly Babies
This would be a memorable introductory demonstration to the topic of cellular respiration. The demonstration involves putting a jelly baby into molten potassium chlorate. The reaction shows the oxidation of the sugar in the jelly baby. Sometimes a high pitched screaming noise can be heard during the reaction. Jelly babies can be used since they have a small enough surface area that the reaction can take place at an appreciable rate, without being explosive
Staying Alive
Although quite a dated publication, section 2 of this booklet (page 16) provides a circus of experiments which illustrate respiration in plants and animals. With each experiment there is a student question sheet (and teacher answers), as well as additional student sheets providing information and asking further questions. This then allows students to compare aerobic and anaerobic respiration on a cellular level. It would be possible to just use some of the question sheets rather than the whole section.
Article on Aerobic respiration
This detailed article, which might prove challenging for some GCSE students, provides useful information about the processes of aerobic respiration, anaerobic respiration, fermentation and photosynthesis. It could be a useful end of topic assessment activity by asking students to produce comparisons of the processes. The task could be differentiated by providing key words which the students should include and a writing frame to scaffold the comparison
Practical Microbiology for Secondary Schools
This practical guide produced by the Society for General Microbiology details a series of practical investigations suitable for GCSE. Included in this guide are investigations on alcohol production using immobilsed yeast cells and effect of antiseptics on microbes.
Practical Biofuel Activities
This booklet contains background information about the science involved in the field of bioenergy and biofuels. There are also a range of practical activities with instructions. The topics look at sustainable development plant science, microbiology, chemistry and a range of other areas of science and technology.
Using analogies
This is an interesting article about the similarities between combustion in an engine and cellular respiration. The idea could be adapted to provide a useful assessment activity or homework by asking students to produce their own comparison of the two processes. The task can be differentiated by providing key words which the students should include (such as fossil fuels, sugar, piston, muscle) and a writing frame to scaffold the comparison.