Question

Endospores are formed to overcome unfavorable conditions in
A. Mucor and Bacillus
B. Bacillus and Clostridium
C. Monococcus and Clostridium
D. Saccharomyces and Clostridium

Answer 1

Hint: The name "endospore" means something of a spore or seed-like from within, but it is not a true spore or not a true offspring as endospore is a dormant, tough structure, and cannot reproduce that is produced by some bacteria in the phylum Firmicutes.

Step by step answer:Lack of nutrients triggers the formation of endospores, and the endospores usually occur in gram-positive bacteria like Bacillus and Clostridium and the examples of such bacterial species that can form endospores are Bacillus cereus, Bacillus anthracis, Bacillus thuringiensis, Clostridium botulinum, and Clostridium tetani. Endospores formation allows bacteria to remain dormant for extended periods, even centuries as there are many reports saying the spores remain viable for over 10,000 years, and even revival of spores millions of years is possible.
In endospore formation, the bacterium divides within its cell wall, and when the environment becomes suitable, the endospore can reactivate itself to the vegetative state but this characteristic of reverting back to the active state is present in very few bacterias. Bacteria produce a single endospore internally and the spore is covered by a thin covering known as the exosporium, that overlies the spore coat and the spore coat is resistant to many toxic molecules and possess certain enzymes that play a role in germination. The cortex is present beneath the spore coat and consists of peptidoglycan in the core structure, while the core wall is present beneath the cortex, and the protoplast or core of the endospore is surrounded by the cortex.
Hence, the correct answer is option (B).

Note: Endospores are found to be resistant to ultraviolet radiation, desiccation, high temperature, extreme freezing, and chemical disinfectants and can survive in conditions lacking nutrients and it has been found that endospores are commonly found in soil and water, and can survive for long periods of time.