The sixth step of glycolysis adds a second phosphate group to the sugar. What is notable about that phosphate?
AIt comes from the breakdown of a fatty acid
BIt comes from the reduction of an amino group
CIt comes from an inorganic ion, not from ATP
DIt comes from a molecule of carbon dioxide
Answer & Solution
Correct answer: C. It comes from an inorganic ion, not from ATP
1. In step six the sugar is oxidized and its high-energy electrons are picked up by the oxidized carrier, producing NADH.
2. The sugar is then phosphorylated by addition of a second phosphate group, producing 1,3-bisphosphoglycerate.
3. That second phosphate group does not require another adenosine triphosphate molecule.
4. This is why the pathway can turn a profit later, since only two adenosine triphosphate molecules were ever invested.
5. Carbon dioxide is never a phosphate donor, so that option confuses two different atoms.
6. Fatty acid breakdown feeds carbon into a later pathway and supplies no phosphate here.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.2 Glycolysis_
Related questions
In type 2 diabetes the oxidation efficiency of NADH is reduced, which affects:Where does the carbon dioxide released during cellular respiration come from?The citric acid cycle is described as amphibolic because its intermediates can also be useHydrogen ions pumped by the electron transport chain accumulate in the:The mobile carrier connecting the first and second complexes to the third is:How many complexes make up the electron transport chain?Making ATP by chemiosmosis is called oxidative phosphorylation because the process involveChemiosmosis accounts for roughly what share of the ATP made during glucose catabolism?