Topic 4 - Investigating Respiration

Question 1

what can you use to show that living organisms produce CO₂ as they respire?

Answer 1

hydrogen-carbonate indicator - it changes from orange to yellow in the presence of CO₂

Question 2

how would you use beans to demonstrate CO₂ production?

Answer 2

1. set up one test tube with dried beans that have been soaked in water for a day. they should be starting to germinate
2. set up another test tube with beans that have been boiled - this is the control
3. put the same amount of hydrogen-carbonate indicator in 2 test tubes
4. place a platform made of gauze into each test tube and place the beans onto this
5. seal the test tube with a rubber bung
6. leave for a set amount of time
7. the hydrogen-carbonate indicator in the test tube with the germinating beans should be yellow

Question 3

how would you show the temperature change produced by respiration?

Answer 3

1. prepare 2 sets of beans (one boiled one germinating)
2. add each set of beaks to a vacuum flask (with some air in it)
3. place a thermometer in each flask and seal the top
4. record the temp daily for a week
5. the germinating beans should have a temp rise, the control beans should stay the same temp