What vessel is used to produce useful substances from cells or their products?

• A. Fermentor
• B. Reactor
• C. Vessel
• D. Bioreactor

Answer: (D)

The idea being tested is using a specialized vessel designed for growing biological systems in order to make useful substances. A bioreactor is built to provide a controlled, sterile environment where cells—whether microbes, plant, or animal cells—can multiply or where products derived from those cells can be produced. It allows precise control of factors like temperature, pH, oxygen levels, nutrients, and mixing, which are essential for efficient production of substances such as proteins, enzymes, vaccines, or other metabolites.

A fermentor is related, but it’s specifically tied to fermentation processes, typically with microorganisms. The broader term bioreactor covers production from cells or their products beyond just fermentation, and a generic vessel or reactor lacks the biological production context.