Video Transcript
Which of the following correctly
describes the correlation between the rate of respiration and carbon dioxide
concentration? (A) The more cells respire, the
lower the carbon dioxide concentration in the blood. (B) The more cells respire, the
higher the carbon dioxide concentration in the blood. (C) There is no correlation between
the rate of respiration and the carbon dioxide concentration in the blood.
This question is asking us to look
for a correlation, which is another word for relationship. And we’re looking for the
relationship between the rate of cellular respiration and the concentration of
carbon dioxide, also written as CO2, in the bloodstream.
When we talk about relationships, I
immediately think graphs. So first, we’ll sketch out three
little graphs, one for each answer. And the 𝑥-axis will represent the
rate of cellular respiration, while the 𝑦-axis represents the carbon dioxide
concentration.
Our first choice states that the
more cells respire, the lower the carbon dioxide concentration in the blood. And we’d expect a graph of this
relationship to look something like this. Choice (B) states that the more
cells respire, the higher the carbon dioxide concentration in the blood. And we can expect a graph of this
relationship to look something like this. Our last answer choice states that
there’s no correlation between the rate of respiration and the carbon dioxide
concentration. So a graph of this relationship
might look something like this.
Let’s start by recalling that
cellular respiration is the process by which our cells convert oxygen and glucose
into water and carbon dioxide, which releases energy that our cells store as
ATP. But what does this all have to do
with our blood?
Well, our lungs take in oxygen from
the atmosphere, which I represented here in blue. And then our bloodstream carries
that oxygen to all the cells of the body that use it to carry out cellular
respiration. As a byproduct of cellular
respiration, our cells generate carbon dioxide, which I’m using black to show
here. And then, once again, our blood
carries that carbon dioxide back to the lungs where it’s removed when we exhale. So if there’s an increase in the
cellular respiration occurring within our cells, we’d expect to see an increase in
the carbon dioxide being produced as a result. And since our blood carries that
carbon dioxide to the lungs to be removed, we’d also expect to see an increase in
carbon dioxide concentration there. And we’d expect the graph of this
information to look something like this.
So the correlation can be described
as the more cells respire, the higher the carbon dioxide concentration in the
blood.
