Question

Where does the Krebs Cycle occur in a prokaryotic cell?

Answer 1

The Krebs Cycle takes place in the cytoplasm of prokaryotic cells due to the absence of organelles like mitochondria, with oxidative phosphorylation occurring at the plasma membrane.

Step-by-step explanation:

The Krebs Cycle in Prokaryotic Cells

In prokaryotic cells, such as bacteria, the Krebs Cycle occurs in the cytoplasm, as opposed to eukaryotic cells where it takes place within the mitochondria. Prokaryotic cells lack organelles like mitochondria, so processes typically associated with these structures in eukaryotes instead occur in the prokaryotic cytoplasm or at the plasma membrane. Furthermore, in prokaryotes, the electron transport chain and the associated process of oxidative phosphorylation, which is closely related to the Krebs Cycle, take place at the plasma membrane.

For instance, the Citric Acid Cycle, another name for the Krebs Cycle, and glycolysis are important metabolic pathways for energy production. In all organisms, glycolysis occurs in the cytoplasm or cytosol. Prokaryotes capable of aerobic respiration utilize these pathways directly in the cytoplasm, using the generated NADH and succinate to fuel ATP synthesis through oxidative phosphorylation at the plasma membrane.

Answer 2

In prokaryotic cells the Krebs cycle takes place in the cytosol.

This is basically because prokaryotic cells have no mitochondria like the eukaryotic cells.

This is somehow advantageous to the prokaryotes because the net yield of ATP is higher than in eukaryotes. Prokaryotes manage to produce 38 molecules of ATP per glucose molecule while eukaryotes produce only 36.

This is because the 2NADH generated in the mitochondria of eukaryotes contribute only 2 ATP instead of 3 because they cannot cross through the inner membrane of the mitochondria while in prokaryotes the 2NADH are free in the cytosol and contribute 3 ATPs each to yield two more than the eukaryotes.

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