Question

Endospore resistance is due to
(a)Dipicolinic acid
(b)Impervious coat
(c)Dehydrated protoplasm
(d)All of the above

Answer 1

Hint: An endospore is a structure produced at unfavorable environmental conditions by some bacteria. Bacterial endospores are immune to antibiotics and most disinfectants as well as to physical agents such as heat, boiling, and drying. Their chemical compound causing dormancy, thick coating, and removal of endospore water are few factors leading to endospore resistance.

Complete answer:
The endospore is composed of DNA, ribosomes, and significant quantities of dipicolinic acid from the bacterium. Dipicolinic acid is a chemical that helps to sustain dormancy and resistance for endospores. 5 to 15 percent of the dry weight of bacterial spores is composed of dipicolinic acid.
Calcium dipicolinate, which is abundant inside the endospore, can stabilize and protect DNA from the endospore. This complex binds molecules of free water, causing spore dehydration. The heat resistance of macromolecules inside the core increases as a consequence. The calcium-dipicolinic acid complex also works by inserting itself between the nucleobases to protect DNA from heat denaturation, thus increasing DNA stability.

Additional Information:
Small acid-soluble proteins (SASPs) saturate the DNA of the endospore and protect it against heat, drying, chemical substances, and radiation. They also work as a source of carbon and energy during germination to form vegetative bacteria.
So, the correct answer is, ‘Dipicolinic acid’.

Note: An endospore is a dormant, tough, and non-reproductive structure that some bacteria make up. Endospore formation is typically caused by a scarcity of nutrients and generally occurs in gram-positive bacteria. Endospores allow bacteria to lie in a dormant position for long periods, even centuries. The endospore can reactivate itself to a vegetative state when the atmosphere becomes more favorable. Examples of endospore-forming bacteria include Bacillus and Clostridium.