A microorganism that is resting and has a hard, shell-like outer covering is called a?

A microorganism that is resting and has a hard, shell-like outer covering is called a?

• A. Spore
• B. Cyst
• C. Bacillus
• D. Pathogen

Answer: (A)

A microorganism that is resting and possesses a hard, shell-like outer covering is known as a spore. Spores are a dormant form of bacteria that can survive extreme conditions such as heat, desiccation, and chemical exposure. They are formed by certain bacteria, primarily within the genera Bacillus and Clostridium, as a survival mechanism. This protective external layer enables spores to withstand unfavorable environments until conditions are suitable for germination and growth. While cysts, another type of protective structure formed by some microorganisms, can also be resistant to environmental stresses, they are generally associated with protozoa and serve a different biological role compared to bacterial spores. Bacillus refers specifically to a rod-shaped bacterium and does not denote a resting form, and pathogens are microorganisms that can cause disease, which may or may not form spores. Therefore, the term spore is the most precise descriptor for a resting microorganism with a hard outer covering.

A microorganism that is resting and possesses a hard, shell-like outer covering is known as a spore. Spores are a dormant form of bacteria that can survive extreme conditions such as heat, desiccation, and chemical exposure. They are formed by certain bacteria, primarily within the genera Bacillus and Clostridium, as a survival mechanism. This protective external layer enables spores to withstand unfavorable environments until conditions are suitable for germination and growth.

While cysts, another type of protective structure formed by some microorganisms, can also be resistant to environmental stresses, they are generally associated with protozoa and serve a different biological role compared to bacterial spores. Bacillus refers specifically to a rod-shaped bacterium and does not denote a resting form, and pathogens are microorganisms that can cause disease, which may or may not form spores. Therefore, the term spore is the most precise descriptor for a resting microorganism with a hard outer covering.