ATI TEAS (Test of Essential Academic Skills) Version 7ScienceEasy
A scientist is investigating a newly discovered bacterium and wants to determine its primary mode of energy production. They observe that the bacterium thrives in environments lacking oxygen and produces lactic acid as a byproduct. What metabolic pathway is this bacterium most likely utilizing?
- AAerobic respiration
- BPhotosynthesis
- CFermentation
- DChemosynthesis
Show answer & explanationAnswer & explanation
Correct answer: C. Fermentation
Fermentation is an anaerobic metabolic process that converts glucose into lactic acid (or ethanol) in the absence of oxygen. The bacterium's thriving in anaerobic conditions and lactic acid production are direct indicators of fermentation.
Why the other options are wrong
- A. Aerobic respiration requires oxygen and produces a much higher ATP yield, with CO2 and H2O as byproducts.
- B. Photosynthesis uses light energy to produce glucose, not relevant to this energy production scenario.
- D. Chemosynthesis uses chemical energy from inorganic compounds, not indicated by lactic acid production.
Fermentation
An anaerobic metabolic process that breaks down glucose without oxygen, typically producing ATP and byproducts like lactic acid or ethanol.
- Occurs in the absence of oxygen.
- Yields a small amount of ATP (2 molecules per glucose).
- Common in bacteria, yeast, and muscle cells during strenuous activity.
Memory trick: No O2? Ferment for the Fuel!