Video Transcript
What three-carbon compound is the
final product of glycolysis? (A) Glyceraldehyde 3-phosphate, (B)
3-PGA, (C) NAD+, (D) glucose, or (E) pyruvate.
Aerobic cellular respiration is the
primary method by which plant and animal cells extract energy from sugars. The first step in this process is
called glycolysis. The main reactant of this reaction
is glucose, a simple six-carbon sugar. The products of glycolysis include
two three-carbon molecules. Let’s take a look at the answers
and determine which correctly names this molecule.
First, we can eliminate all of the
answers that are not three-carbon molecules. We know glucose is a six-carbon
molecule and is the reactant of glycolysis, so we can eliminate answer (D). NAD contains many more carbons than
three, so answer (C) can be eliminated. Now let’s discuss answer (A). Glyceraldehyde 3-phosphate is a
three-carbon molecule that occurs as an intermediate in glycolysis. It contains an additional phosphate
group that the final product of glycolysis does not have. So this answer is also incorrect
because it is an intermediate and we are looking for the final product of
glycolysis. 3-PGA is the conjugate of
glyceraldehyde 3-phosphate, so answer (B) can be eliminated.
The correct answer is (E). The three-carbon molecule that is
the final product of glycolysis is pyruvate.
