Final answer:
Sporulation allows some gram-positive bacteria to survive harsh conditions by forming protective endospores, a process not possible for gram-negative bacteria due to the absence of genes and suitable cell wall structure for endospore formation.
Step-by-step explanation:
Some gram-positive bacteria produce spores under harsh conditions to protect their genetic material and ensure survival. This process is called sporulation, which usually begins when nutrients become scarce or environmental conditions worsen. The gram-positive bacteria have a thick peptidoglycan cell wall that allows for the formation of this protective structure, whereas the thinner cell wall of gram-negative bacteria, with its outer membrane, is not conducive to spore formation. Due to these structural differences, the ability to form endospores is almost exclusively seen in gram-positive bacteria, particularly in the genera Bacillus and Clostridium. These spores can withstand extreme conditions for extended periods, making bacteria like B. anthracis and C. botulinum difficult to eliminate.
Sporulation is stated as never occurring in gram-negative bacteria because they lack the necessary structural components for endospore formation. The genes responsible for endospore formation are not present in the gram-negative bacteria, and their cell wall architecture does not support the complex endosporulation process. This characteristic is strictly associated with certain gram-positive bacteria, and it has significant implications for medical sterilization practices, as endospores require special methods to be effectively destroyed.