Question

Sequentially arrange the steps involved in cryopreservation of plant cells in order of their occurrence.
A. Raising sterile tissue culture
B. Determination of viability
C. Freezing, Storage
D. Addition of cryoprotectants.
Choose the correct answer from the options given below:

• A. A, D, C, B
• B. A, B, C, D
• C. B, A, D, C
• D. C, B, D, A

Hint:

Think of cryopreservation like preparing a valuable item for long-term storage. First, you get the item (A. raise culture). Then, you wrap it in protective material (D. add cryoprotectants). Next, you put it in the storage unit (C. freeze). Finally, when you take it out, you check if it's still in good condition (B. determine viability).

Answer 1

The Correct Option is A

Step 1: Concept Overview:
This question concerns the correct sequence of steps in cryopreservation, a method for preserving biological material (like plant cells) at extremely low temperatures, typically in liquid nitrogen (\(-196^\circ\)C).
Step 2: Step-by-Step Breakdown:
Let's examine the logical order of the process:

A. Sterile Tissue Culture Establishment: The process begins by establishing a healthy, sterile, and actively growing culture of plant cells or tissues. This provides the starting material for preservation.
D. Cryoprotectant Application: Prior to freezing, cells must be treated with cryoprotectants (e.g., DMSO, glycerol). These agents prevent ice crystal formation, thus protecting cells from damage during freezing. This is a critical pre-treatment.
C. Freezing and Storage: Following cryoprotectant application, cells undergo controlled cooling to freeze them before being transferred to liquid nitrogen for long-term storage.
B. Viability Assessment: After storage and thawing, it's crucial to assess cell viability to determine if they survived the freezing and thawing process. This can be done using staining methods (e.g., TTC or fluorescein diacetate) as a quality control measure.
Step 3: Solution:
The correct sequence is: Culture establishment (A), cryoprotectant application (D), freezing and storage (C), and viability assessment (B). Therefore, the correct order is A, D, C, B.