Question

What is totipotency in biology?

• A. The ability of a cell to differentiate into various specialized cell types
• B. The ability of a cell to divide by mitosis
• C. The ability of a cell to replicate its celluar components
• D. The ability of a cell to replicate its DNA

Hint:

In plant tissue culture, auxin and cytokinin concentrations are used to regulate totipotent cells:
- High Auxin : Low Cytokinin $\rightarrow$ induces root differentiation.
- Low Auxin : High Cytokinin $\rightarrow$ induces shoot differentiation.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Cellular totipotency is the biological capacity of an individual cell to divide, differentiate, and regenerate into a complete, multicellular organism when provided with appropriate environmental and hormonal signals.

Step 2: Detailed Explanation:
- In plants, somatic cells retain their complete genetic blueprint and do not lose their developmental potential during differentiation.
- Under appropriate in vitro conditions, these differentiated cells can be induced to de-differentiate back into a meristematic state (callus) and subsequently re-differentiate into specialized tissues (roots, shoots, or vascular systems). This property is known as totipotency.
- Cellular totipotency is the theoretical foundation of plant tissue culture. It enables techniques such as micropropagation, somatic embryogenesis, and the regeneration of transgenic plants from single transformed cells.
- Gottlieb Haberlandt first proposed this concept in 1902. It was later demonstrated experimentally by Steward (1958) using isolated carrot phloem cells, which regenerated into complete carrot plants.
- Simple mitotic division (Option 2) or DNA replication (Option 4) are common to most dividing cells, but they do not describe the capacity to differentiate into multiple cell types or regenerate a whole organism.

Step 3: Final Answer:
Totipotency is the ability of a cell to differentiate and develop into a complete organism.