Video Transcript
Which of the following examples is
a situation where the muscle cells in the body are most likely to be relying mainly
on aerobic respiration to supply their energy requirements? (A) A person running a marathon
distance of 26 miles over four hours. (B) A child sprinting 50 meters
down a hallway in eight seconds. (C) A rabbit in a garden spotting a
fox and immediately jumping away.
Cellular respiration is the process
of converting the energy in glucose to ATP for our cells. It can occur in either the presence
or absence of oxygen. Aerobic respiration uses oxygen and
is often the favored process because it produces a large amount of ATP per glucose
molecule. However, sometimes oxygen is not
available for this process to occur. When there’s no oxygen available,
the body will utilize anaerobic respiration in order to continue generating
energy.
Now that we have reviewed how the
body generates energy, we can take another look at our question.
We are presented with three
situations requiring energy. The first situation describes a
person running a marathon over the course of four hours. Because these energy demands are
spread over a long period of time, this person should be able to get enough oxygen
for aerobic respiration. So this seems to be the correct
answer, but let’s look at the other two choices to be sure.
The second situation involves a
child sprinting down a hallway, which would require a burst of energy in a short
amount of time. Because this child requires high
amounts of energy over a period of eight seconds, it’s unlikely they’ll be able to
take in enough oxygen to meet this demand. So the child’s cells are likely
using anaerobic respiration. And this answer is incorrect.
In the last situation, a rabbit
immediately jumps away after spotting a fox. This is similar to the child
sprinting down the hallway, because the rabbit will need to use high amounts of
energy in a short period of time. So an adequate amount of oxygen is
unlikely to be delivered to the cells in this time, and anaerobic respiration will
predominate. So this answer is incorrect.
Therefore, the option that
correctly identifies aerobic respiration is given by answer choice (A): a person
running a marathon distance of 26 miles over four hours.
