Video Transcript
Which of the following best defines metabolism? (A) Metabolism is the sum of all the energy lost from an organism. (B) Metabolism is the sum of the chemical reactions that occur in each cell of an
organism. (C) Metabolism is how quickly the body digests a meal. (D) Metabolism is how quickly a person can lose weight. Or (E) metabolism is the total energy input divided by the total energy output of an
organism.
There are many misconceptions about metabolism in humans. This question is asking us to find the answer choice that best defines
metabolism. And to do this, we will need to address some of these misconceptions that have been
stated in the answer choices.
You might have heard before that slim, particularly fit, or energetic people have an
especially high metabolism. This is not necessarily correct, as metabolism is not simply how quickly someone
digests food, how little weight someone might gain from their food, nor does it
describe how quickly they might lose this weight. With this information, we can eliminate answer options (C) and (D) as they both
simplify metabolism too much.
Metabolism has more to do with the chemical reactions that occur within our body
cells or the cells of any other living organism for that matter. In fact, metabolism is the sum of all the chemical reactions that occur in a cell or
body of any living thing. Metabolic reactions are occurring in all of your cells all of the time, and our
metabolism is what helps us to maintain life.
Now we are able to answer our question correctly. The answer choice that best defines metabolism is (B). Metabolism is the sum of the chemical reactions that occur in each cell of an
organism.
