CHAPTER 7 REVIEW
(Pages 232–233)
Part 1
1. C
2. B
3. B
4. D
5. C
6. B
7. B
8. 4, 1, 6, 5
9. 32.4 %
Part 2
10. The energy is lost as heat or thermal energy.
11. (a) The net gain in ATP after one molecule of glucose undergoes cellular respiration is
36 ATP.
(b) The net gain in ATP after one molecule of glucose undergoes alcoholic fermentation is
2 ATP.
12. Glycolysis occurs in the cytoplasm. Pyruvate oxidation occurs in the mitochondrial matrix.
The Krebs cycle occurs in the mitochondrial matrix. The electron transport chain and
chemiosmosis occur in the inner membrane of the mitochondria.
13. NADH must be converted into NAD in the electron transport chain for hydrogens to attach to
NAD in glycolysis. If oxygen is not present, the electron transport chain will not work,
resulting in a buildup of NADH and a lack of NAD, causing glycolysis to stop.
14. Yeast cells produce ATP from glucose by alcoholic fermentation. NADH passes its hydrogen
atoms to acetylaldehyde, which is formed when a carbon dioxide molecule is removed from
pyruvate using pyruvate decarboxylase. This produces ATP, ethanol, and carbon dioxide.
15. Lactic acid is more likely to accumulate.
16. Walking breaks would allow lactic acid to be transported to the liver, where it is converted
into pyruvate, and continue through the process of aerobic respiration.
17. It is essential that muscle cells continue to convert pyruvate to lactate or else the muscle cells
would cease to contract and the cells would die.
18. Test tube A contains aerobic yeast. You can identify it because it has a faster growth rate as a
result of higher ATP production.
19. Seal the test tubes and observe the effect of decreased oxygen on yeast growth.
20. Ethanol is produced commercially in anaerobic environments using plant material mixed with
bacteria, resulting in the formation of ethanol. The ethanol can be purified and extracted
using distillation. Sugar cane and grain are the primary sources of ethanol production.
By replacing petroleum products with ethanol, fewer greenhouse gases will enter the
environment, resulting in reduced greenhouse effect.
A great deal of energy is input into the production of ethanol currently. Each of these
inputs comes from petroleum products. With further research, the production of ethanol will
increase the difference between the energy output and the energy input as technologies
improve.
Genetic engineering is being used to increase the efficiency at which bacteria
produce ethanol during anaerobic cellular respiration. Research is also underway to allow for
greater storage of sunlight as chemical energy during photosynthesis.
Copyright © 2008 Thomson Nelson
Unit 20 C Solutions Manual
119
Canada has the ability to produce large amounts of ethanol due to our large crop
production of grain and other plant material. Canada’s ethanol production is expected to triple
to produce over 650 million litres by 2010.
21.
22. The runner’s resting VO2 max is 15 mL/kg/min.
23. The runner’s oxygen consumption is 1125 mL/min (15 mL/kg/min × 75 kg) at rest and
6750 mL/min (90 mL/kg/min × 75 kg) during his highest VO2 max.
24. During the first 60 min, the runner’s body is acclimating to the exercise. From 60 to 150 min,
his body is unable to keep up a high VO2 max and plateaus at 65 mL/kg/min. After 150 min
and until the end of the race, his body slowly lowers its VO2 max.
25. The oxygen consumption after the race will still be high due to oxygen debt. The excess
oxygen requirement will be made by the liver to convert the lactate into pyruvate using
oxygen. This will occur only after the muscle requirements for oxygen are met.
UNIT 20 C PERFORMANCE TASK: STUDENT AQUARIST
Please note that what follows is an example of a performance task. Students’ results will vary
depending on the condition on which the student focuses.
Purpose
To determine how temperature, light conditions, pH, dissolved ammonia, dissolved oxygen, and
dissolved carbon dioxide affect the metabolic health of plants, fish, and snails in a freshwater
ecosystem
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Unit 20 C Solutions Manual
Copyright © 2008 Thomson Nelson