Question

In animal cell culture, a $CO_{2}$ enriched atmosphere in the incubation chamber is used:

• A. for supplying $CO_{2}$ for the metabolic reaction.
• B. to control pH by generating carbonic acid.
• C. to control pH by generating bicarbonate.
• D. to aid photosynthetic reaction.

Hint:

$CO_{2}$ Incubator = pH Control via Bicarbonate Buffer.

Answer 1

The Correct Option is B

Step 1: Concept
Maintaining a stable physiological pH (usually 7.2 to 7.4) is critical for animal cell survival in vitro.

Step 2: Meaning
Most culture media use a bicarbonate ($HCO_{3}^{-}$) buffering system.

Step 3: Analysis
The $CO_{2}$ in the incubator dissolves into the medium, reacting with water to form carbonic acid ($H_{2}CO_{3}$). This establishes an equilibrium with the bicarbonate in the medium. By keeping the $CO_{2}$ level constant (usually 5%), the incubator prevents the medium from becoming too alkaline as cells produce acidic waste.

Step 4: Conclusion
The $CO_{2}$ is primarily used for pH regulation through the bicarbonate-carbonic acid buffer system. Final Answer: (B)