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Context:

Scientists have discovered bacteria that generate electricity through extracellular respiration.

News in Detail

Scientists at Rice University discovered that certain bacteria can "breathe" electricity instead of oxygen. This process, called extracellular respiration, helps them survive in places with no oxygen—like deep-sea vents or even human gut.

Normally, living beings (including humans) need oxygen to break down food and produce energy. But these bacteria use extracellular electron transfer (EET)—they push electrons out of their cells onto surfaces (like metals), creating an electric current.

How Exactly Do They Generate Electricity?

They use naphthoquinones (special molecules) as "electron couriers" to transfer electrons outside their cells.
This electron flow mimics how batteries work, allowing bacteria to generate energy without oxygen.
Researchers confirmed this using computer simulations of bacteria growing on conductive surfaces (like metals) in oxygen-free environments.

Significance of this Discovery

Renewable Energy from Waste

Microbial Fuel Cells (MFCs) can use these bacteria to turn organic waste (like sewage or farm waste) into electricity.
Example: Wastewater treatment plants could generate power while cleaning water.

Fighting Climate Change

These bacteria can use CO₂ (like plants in photosynthesis) to produce energy, offering a cleaner alternative to fossil fuels.

Bioremediation (Cleaning Pollution)

They can convert toxic metals (like arsenic or mercury) into less harmful forms by transferring electrons to them.
Useful for cleaning contaminated soil and water.

Bioelectronic Sensors

Since they work without oxygen, they can be used in:

Medical sensors (e.g., detecting gut infections).
Environmental monitors (e.g., tracking pollution in rivers).
Space missions (surviving harsh, oxygen-free conditions).

Future Possibilities

Self-Powered Waste Treatment: Factories could clean wastewater while generating electricity.

Space Exploration: These bacteria could help sustain life in oxygen-poor environments like Mars.

Carbon-Neutral Energy: If scaled up, they could provide a new form of green electricity.

Conclusion

This discovery opens doors for sustainable energy, pollution control, and advanced biotech. Instead of relying on fossil fuels, we might soon harness living batteries—tiny bacteria that breathe electricity.

Source:

NDTV

PRACTICE QUESTION

Q. The extracellular respiration process mediated by naphthoquinones allows bacteria to perform which of the following functions without the presence of oxygen?

1. Breaking down food

2. Generating energy

3. Synthesizing cell wall materials

Which of the functions given above is/are directly enabled by this process according to the sources?

A) 1 only

B) 2 only

C) 1 and 2

D) 1, 2 and 3

Answer: B

Explanation:

The extracellular respiration process mediated by naphthoquinones enables bacteria to generate energy in the absence of oxygen. This is achieved through extracellular electron transfer (EET), where naphthoquinones act as electron shuttles, allowing bacteria to maintain redox balance and produce energy without relying on oxygen as the terminal electron acceptor.

While this process supports energy generation, it does not directly involve the breakdown of food (i.e., the initial stages of metabolism) or the synthesis of cell wall materials. These functions are part of other metabolic pathways and are not directly enabled by naphthoquinone-mediated extracellular respiration.