Question

Oxidation of glucose is one of the most important reactions in living cells. What is the number of ATP molecules generated in a cell from one molecule of glucose?
A) \[32\]
B) \[12\]
C) \[18\]
D) \[28\]

Answer 1

Hint: The number of ATP molecules generated via the catabolism of glucose can vary substantially. For example, the number of hydrogen ions the electron transport chain complexes can pump through the membrane varies between species. Another source of variance occurs during the shuttle of electrons across the membranes of the mitochondria.

Complete answer:
Adenosine triphosphate, also known as ATP, is a molecule that carries energy within cells. It is the main energy currency of the cell, and it is an end product of the processes of photophosphorylation. In a eukaryotic cell, the process of cellular respiration can metabolize one molecule of glucose into 30 to 32 ATP. The process of glycolysis only produces two ATP, while all the rest are produced during the electron transport chain. Clearly, the electron transport chain is vastly more efficient, but it can only be carried out in the presence of oxygen. The NADH generated from glycolysis cannot easily enter mitochondria. Thus, electrons are picked up on the inside of mitochondria by either \[NA{D^ + }\]or\[FA{D^ + }.\]These\[FA{D^ + }\]molecules can transport fewer ions; consequently, fewer ATP molecules are generated when \[FA{D^ + }\]acts as a carrier. \[NA{D^ + }\]is used as the electron transporter in the liver, and \[FA{D^ + }\]acts in the brain.

So, the correct answer is “Option A”.

Note:
We have to remember that the lipids, such as cholesterol and triglycerides, are also made from intermediates in these pathways, and both amino acids and triglycerides are broken down for energy through these pathways. Overall, in living systems, these pathways of glucose catabolism extract about $34$ percent of the energy contained in glucose.