Question

Assertion (A): In plant vacuole, the concentration is higher than the cytoplasm.
Reason (R): Tonoplast facilitates the transport of ions and other materials against concentration gradient.
Identify the correct option from the following
Options:

• (A) and (R) are true, (R) is correct explanation for (A)
• (A) and (R) are true, but (R) is not correct explanation for (A)
• (A) is true, but (R) is false
• (A) is false, but (R) is true

Hint:

For assertion-reason questions:
- Evaluate (A) and (R) independently for truth.
- Check if (R) directly causes or explains (A).
- Understand plant cell mechanisms (e.g., tonoplast’s role in active transport).

Answer 1

The Correct Option is A

Step 1: Evaluate the Assertion (A).
The plant vacuole stores ions, nutrients, and waste, typically having a higher solute concentration than the cytoplasm. This helps maintain turgor pressure and store materials, while the cytoplasm has a lower concentration due to its metabolic role.
Conclusion: Assertion (A) is true.
Step 2: Evaluate the Reason (R).
The tonoplast, i.e., the vacuolar membrane, contains proton pumps (e.g., H\textsuperscript{+}-ATPases) that generate a proton gradient. This gradient drives the active transport of ions and other materials into the vacuole against their concentration gradient. This process is well-documented in plant cells. Conclusion: Reason (R) is true.
Step 3: Determine if R explains A.
The higher concentration in the vacuole (A) is due to the tonoplast’s active transport of ions and materials against the concentration gradient (R). This mechanism directly explains the concentration difference.
Conclusion: R explains A.
Step 4: Check the options.
Option (1) matches: (A) and (R) are true, and (R) explains (A).
Step 5: Verify option (4) as requested.
Option (4) is: (A) is false, but (R) is true:
% Option (A) is true (vacuole concentration is higher), not false.
% Option (R) is true (tonoplast facilitates active transport).
Option (4) is incorrect since (A) is not false.
Final Answer: (1) (A) and (R) are true, (R) is correct explanation for (A).