Question

What is used to provide a constant flow of growth medium to keep microorganisms in a logarithmic phase of growth?

• A. Chemostat
• B. Autoclave
• C. Laminar flow
• D. Fermentor

Hint:

Think of a continuous culture system, not a batch culture.

Answer 1

The Correct Option is A

Step 1: The key phrase here is constant flow of fresh medium plus keeping cells in log phase, which points to continuous culture technique rather than sterilization or containment equipment.

A chemostat works on the principle of a fixed dilution rate: fresh medium enters and spent medium with cells leaves at the same rate, so growth rate can be controlled and held at a steady exponential state indefinitely.

Autoclave (moist heat sterilization), laminar flow (sterile air workstation) and fermentor (a bioreactor vessel, which may run in batch, fed batch or continuous mode) do not by themselves describe this specific continuous-feed, log-phase-maintaining function. Answer: Chemostat.