Question

In cryopreservation, tissues or seeds are preserved and maintained at ________ temperature for the purpose of long-term storage.

• A. -150 to -190 degree C
• B. 0 degree C
• C. -18 degree C
• D. -50 to -60 degree C

Hint:

Cryopreservation strictly refers to ultra-low temperature storage using liquid nitrogen (ranging from \(-150^{\circ}\text{C}\) down to \(-196^{\circ}\text{C}\)).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Cryopreservation is a preservation technique used to store delicate biological materials (such as seeds, pollen, or plant tissue cultures) at ultra-low temperatures, halting all metabolic and biochemical processes to ensure long-term genetic stability.

Step 2: Detailed Explanation:
To successfully preserve tissues without forming intracellular ice crystals that damage cell walls, specimens are cooled to ultra-low temperatures using liquid nitrogen.
Liquid nitrogen exists in a liquid state at temperatures below \(-196^{\circ}\text{C}\).
Cryopreservation facilities typically maintain samples in the vapor or liquid phase of liquid nitrogen, keeping temperatures in the range of \(-150^{\circ}\text{C}\) to \(-196^{\circ}\text{C}\) (or up to \(-190^{\circ}\text{C}\)).
Standard freezing at \(-18^{\circ}\text{C}\) or \(-50^{\circ}\text{C}\) is insufficient to halt metabolic degradation completely and does not qualify as cryopreservation.

Step 3: Final Answer:
The cryogenic temperature range used for cryopreservation is -150 to -190 \(^{\circ}\text{C}\).