Common Features of Aerobic and Anaerobic Bacterial Cultures: Glycolysis Explained

Glycolysis stands out as the key common metabolic pathway shared by both aerobic and anaerobic bacterial cultures. This process breaks down glucose without needing oxygen, making it essential for energy production in diverse environments. Understanding these shared and distinct features helps clarify bacterial metabolism in exams like GATE Biotechnology.

Correct Answer
The correct option is (A) Glycolysis. This pathway occurs universally in bacteria regardless of oxygen availability, serving as the initial step in glucose catabolism.​

Option Breakdown

• (A) Glycolysis: This 10-step process converts one glucose molecule to two pyruvates, yielding a net of 2 ATP and 2 NADH. It happens in the cytoplasm of all bacteria, acting as the anaerobic entry point to respiration or fermentation in oxygen-free conditions.​

• (B) NAD+ is the oxidising agent: NAD+ oxidizes glyceraldehyde-3-phosphate in glycolysis for both types, but in anaerobes, NADH regenerates via fermentation (e.g., lactate or ethanol), not always matching aerobic electron transport reliance.​

• (C) Oxidative phosphorylation: Exclusive to aerobic bacteria, this occurs in the membrane using oxygen as the final electron acceptor to generate up to 34 ATP via proton gradient-driven ATP synthase. Anaerobes lack this oxygen-dependent step.​

• (D) Two net ATP molecules formed per glucose molecule: True for anaerobic glycolysis or fermentation (after substrate-level phosphorylation), but aerobes gain far more (around 36-38 ATP total) through full oxidation, so not common.​