Question

Which of the following is NOT correct for vacuole?

• A. Storage of reserves
• B. Contains different types of enzymes involved in breakdown and recycling
• C. Accumulate toxic compounds used in defense against microbial pathogens
• D. Present in a fixed number and size

Hint:

The vacuole membrane is called the tonoplast. It helps maintain turgor pressure, which keeps plants upright.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The vacuole is a membrane-bound organelle found in all plant and fungal cells and some protist, animal, and bacterial cells. In plants, the large central vacuole can occupy up to 90% of the cell volume.

Step 2: Detailed Explanation:
- Option 1: Vacuoles act as storage reservoirs for water, salts, nutrients (reserves like proteins in seeds), and metabolic waste. This is correct.
- Option 2: Vacuoles (specifically in plants and fungi) function similarly to lysosomes in animal cells; they contain hydrolytic enzymes that degrade proteins, nucleic acids, and lipids for recycling. This is correct.
- Option 3: Many secondary metabolites, such as alkaloids or tannins, which are toxic to herbivores or microbes, are sequestered in the vacuole as a defense mechanism. This is correct.
- Option 4: Vacuoles are highly dynamic. Their size and number change significantly during the life of a cell. Young plant cells often have several small vacuoles that fuse into a single large central vacuole as the cell matures. Their size also fluctuates depending on the osmotic state (turgor) of the cell. They are not present in a "fixed number and size."

Step 3: Final Answer:
Since vacuoles are dynamic and vary between cell types and ages, statement 4 is incorrect.