RESPIRATION
Student Name ______________________________
1.
1. Complete the following equation, which is a summary of aerobic respiration.
C6H12O6 + 6O2  _________________________________
2. Aerobic respiration is a two-stage process. The first stage takes place in the _____________________. while the
second stage take place in the __________________________
3. Name a substance that yeast can use to make ethanol. _________________________________
4. Name a substance produced during aerobic respiration that is not produced during fermentation. __________
5. _____________________ respiration is the release of energy in the absence of oxygen
6. Give an account of a chemical test to demonstrate that alcohol (ethanol) has been produced. (Include the initial
colour and final colour of the test). _____________________________________________
_________________________________________________________________________________
7. Why does fermentation eventually cease? ________________________________________________
8. When lactic acid builds up in the blood, a person is said to be in oxygen debt. This debt must eventually be paid.
Suggest how the debt is paid. _________________________________________
9. Anaerobic respiration by micro-organisms is called fermentation. Give one example of industrial fermentation,
including the type of micro-organism and the substance produced. ________________
__________________________________________________________________________________
10. In the first stage of respiration there is a release of ATP as glucose is converted to another substance. Name this
other substance. _________________________________
11. In respiration the acetyl group enters a cycle of reactions.
What name is given to this cycle? _________________________________
Where in the cell does this cycle take place? _________________________________
12. To what is pyruvic acid (pyruvate) converted under anaerobic conditions in:
1. Yeast _________________________________
2. A human muscle cell _________________________________
13. Under aerobic conditions pyruvic acid (pyruvate) is converted to an acetyl group and in the process a small
molecule is released. Name this small molecule. _________________________________
14. Identify X and Y in the following equation which is a summary of aerobic respiration.
C6H12O6 +
6X

6Y +
6H20
_________________________________________________
15. If yeast cells are kept under anaerobic conditions, alcohol (ethanol) and another substance are produced.
(i) What are anaerobic conditions? _________________________________ __________________
(ii) Name the other substance produced. _________________________________
16. Comment on the amount of energy released in the first stage of respiration. ____________________
17. What name is given to the first stage of respiration? _________________________________
18. Where in a cell does this first stage of respiration take place? _________________________________
19. Does the second stage of respiration require oxygen? _________________________________
20. Where in the cell does the second stage of respiration take place? ____________________________
21. To what substance is glucose normally converted in the first stage of respiration? ______________
Is oxygen required for this conversion? _________________________________
22. Comment on the amount of energy released in the second stage of respiration.
__________________________________________________________________________________
23. Name a compound to which pyruvic acid (pyruvate) may be converted, in the absence of oxygen.
__________________________________________________________________
24. The first stage of respiration takes place in the cytosol. What is the cytosol?
__________________________________________________________________
25. Is oxygen required for the second stage of aerobic respiration? __________________
26. Suggest a situation in which some cells in the human body may not be able to engage in the second stage of
aerobic respiration __________________________________________________________
2. The apparatus below may be used to demonstrate
anaerobic respiration in yeast. The water was boiled and
cooled before adding the yeast.
(i) Why was the water boiled before adding the yeast?
____________________________________________
(ii) Why do you think a layer of oil has been put on top of the
water? ____________________________________
____________________________________________
(iii) Suggest a control for this experiment._________________________________________
________________________________________________________________________________________
(iv) Give two industrial uses of the anaerobic respiration of yeast. ________________________________
__________________________________________________________________________________
3. The diagram shows part of a plant cell.
(a) Name the organelle labelled A. ____________________
(b) (i) Name a tissue in plants and in animals where you might
expect to find a relatively large number of these organelles.
________________________________
(ii) Give a reason for your choice.__________________________
(c) Draw a large labelled diagram of this organelle