Question

In prokaryotic cells, the number of ATP generated from one glucose molecule is _______
(a)36
(b)38
(c)34
(d)32

Answer 1

Hint: in the bacterial cell, since there are no mitochondria, the whole process of respiration occurs within the cytoplasm so no ATP is consumed in transporting across the organelle. In eukaryotes, the Electron Transport Chain that yields the maximum ATPs is located in the inner membrane of the mitochondria. So, the NADH made during the glycolysis in the cytoplasm has to be transferred to the mitochondria using the shuttle system and for this, 2 ATPs are consumed.

Complete answer:
In prokaryotes, there are no mitochondria, the whole process of respiration occurs within the cytoplasm so no ATP is consumed in transporting across the organelle. Therefore, 38 ATPs are made from one glucose in bacteria while 36 are made in a eukaryotic cell. In Prokaryotes, the respiratory chain and phosphorylation chain are located in the Plasma membrane. In prokaryotes and eukaryotes, some of the NADH is generated by the cytosolic Glycolysis. The oxidation of NADH is essentially not only to provide electrons for the electron transport chain but also to feed free NAD back to the glycolytic pathway. Thus oxidation occurs in the respiratory chain, which is located in plasma membranes in Prokaryotes, and in the inner mitochondrial membrane in eukaryotes. The plasma membrane of prokaryotes is permeable to NADH. So, NADH can readily and directly get into the plasma membrane. But, the inner mitochondrial membrane is impermeable to NADH. So, the electrons from the cytosolic NADH are carried across it as reducing equivalents. This is accomplished by an appropriate shuttle system through an indirect route with the help of a reduced substrate. For this, 2 ATPs are consumed.

Additional Information: -NADH is the major source of electrons for the respiratory chain.
-The shuttle system collects cystolic hydrogen and transports it across the mitochondrial membrane as a metabolite constituent.
-It the all shuttle system two are important; malate aspartate shuttle cycle and glycerol -3- phosphate shuttle cycle.
So, the correct answer is ‘38’

Note: - Glycolytic degradation of one molecule of glucose involves the utilization of 2 ATP molecules and the production of 4 ATP molecules.
-So, there is a net gain of 2 ATP molecules. If the initial substrate is glycogen, there would be a net yield of 3 ATP molecules.
-The degradation of glucose to pyruvic acid involves the release of about 195 kilojoules of free energy also.