Video Transcript
Which of the following statements
about respiration in animals is correct? (A) Aerobic respiration transfers
less energy than anaerobic respiration. (B) Anaerobic respiration transfers
less energy than aerobic respiration. (C) Anaerobic respiration generates
more carbon dioxide than aerobic respiration. (D) Aerobic respiration generates
more lactic acid than anaerobic respiration. Or (E) over the same period of
time, anaerobic and aerobic respiration will transfer the same amount of energy.
The answer choices are all
comparing anaerobic and aerobic respiration. Which of these statements is true
about respiration in animal cells? Let’s review what aerobic and
anaerobic respiration in animal cells require and what these reactions produce to
work out the correct answer.
Aerobic respiration converts
glucose and oxygen into carbon dioxide and water, in addition to releasing energy
for cells to use. Aerobic respiration releases quite
a lot of energy and temporarily stores it in the high-energy bonds of 38 molecules
of ATP per molecule of glucose. ATP molecules can be broken down
quickly to release this energy again when it’s required for cellular processes.
Anaerobic respiration also requires
glucose. However, it does not require
oxygen. It produces a substance called
lactic acid and releases far less energy than aerobic respiration. Only two molecules of ATP are
produced in anaerobic respiration compared to 38 in aerobic. As anaerobic respiration does not
produce any carbon dioxide, let alone more than aerobic respiration, which produces
six molecules of carbon dioxide per molecule of glucose, option (C) is
incorrect. Option (D) is also incorrect, as
anaerobic respiration produces lactic acid, not aerobic respiration.
The remaining answers, (A), (B),
and (E), compare which method of respiration releases more energy, which would be
transferred to molecules of ATP. Anaerobic respiration in animals
functions effectively as a backup system of producing ATP when not much oxygen is
available. It has some important
disadvantages, one of which is that it is less efficient. Aerobic respiration produces 38
molecules of ATP per molecule of glucose, while anaerobic respiration only produces
two.
With this information, we can
confirm that the correct answer is option (B). Anaerobic respiration transfers
less energy than aerobic respiration.
