When environmental conditions are unfavorable to their existence some bacterial species form: Answers: A – E A Sex pili B Endospores C Capsules D Protoplasts E Plasmids
The correct answer and explanation is:
The correct answer is B Endospores.
Explanation:
Certain bacterial species have the ability to survive harsh or unfavorable environmental conditions by forming endospores. Endospores are highly resistant, dormant structures produced inside the bacterial cell when conditions such as nutrient depletion, extreme temperatures, desiccation, or chemical exposure threaten survival. The formation of an endospore allows the bacterium to protect its genetic material and essential cellular components until favorable conditions return.
Endospores are characterized by their tough outer layers, which include a thick protective coat made of proteins and a cortex rich in peptidoglycan. This structure makes them resistant to heat, radiation, desiccation, and many chemical disinfectants. When environmental conditions improve, the endospore can germinate, returning to a metabolically active vegetative bacterial cell.
This process is mainly seen in certain Gram-positive bacteria, especially genera like Bacillus and Clostridium. For example, Bacillus anthracis, the causative agent of anthrax, and Clostridium botulinum, which causes botulism, form endospores to survive in adverse conditions.
The other options do not serve the same function:
- A Sex pili are hair-like appendages used for bacterial conjugation, allowing transfer of genetic material between bacteria, but they do not help survive unfavorable environments.
- C Capsules are protective layers around some bacteria that help evade the immune system or prevent desiccation, but they are not dormant survival structures.
- D Protoplasts are bacterial cells stripped of their cell walls, often artificially created in labs, and are usually more vulnerable rather than protective.
- E Plasmids are small, circular DNA molecules independent of chromosomal DNA, involved in genetic exchange, but they do not protect bacteria from harsh conditions.
In summary, endospores are the specialized survival structures enabling certain bacteria to withstand extreme environmental stress until conditions become suitable for growth again.