Video Transcript
The diagram provided shows a basic
outline of the process of glycolysis. The circles are used to represent
the number of carbons in the compounds involved. What compound has been replaced by
the letter Z?
The question asks us about
glycolysis, which is the first stage in the process of cellular respiration. Cells perform respiration to
extract energy from sugar and transfer this energy to a molecule called ATP. Aerobic cellular respiration is a
multistep process. These steps are glycolysis, the
link reaction, the Krebs cycle, and oxidative phosphorylation. Let’s discuss glycolysis in more
detail.
During glycolysis, a six-carbon
compound is converted, via a series of reactions, into two three-carbon compounds
called pyruvate. The pyruvate produced moves on to
the next stage in cellular respiration, the link reaction.
We have already discussed how
glycolysis is the first stage in cellular respiration, which is, by definition, a
process in living organisms through which carbon-containing compounds, such as
glucose, are broken down to release energy in the form of ATP. So, in glycolysis, we start with
our carbon-containing compound, the first reactant in this complex multistage
process. And following a series of reactions
and processes, we reach the final stage of respiration, oxidative phosphorylation,
during which many molecules of ATP are produced.
So, to answer the question, we need
to identify which six-carbon compound might be broken down to release ATP during
cellular respiration. The correct answer is given in our
definition. Glucose is a six-carbon compound
and the most common respiratory substrate. So the compound in our diagram that
has been replaced by the letter Z is glucose.
