Vacuole in a plant cell

Options

A. Lacks membrane and contains water and excretory substances
B. Is membrane - bound and contains storage proteins and lipids
C. Is membrane - bound and contains water and excretory substances
D. Lacks membrane and contains air

Answer

### Step-by-Step Solution for the Question: Vacuole in a Plant Cell

1. **Definition of Vacuole**:
- A vacuole is a membrane-bound organelle found in eukaryotic cells, particularly prominent in plant cells.

**Hint**: Remember that vacuoles are not just any structure; they are specifically membrane-bound.

2. **Structure of Vacuole**:
- Vacuoles are essentially closed sacs or vesicles that can vary in shape and size depending on their contents.

**Hint**: Think of vacuoles as flexible storage bags that can change based on what they hold.

3. **Composition of Vacuole**:
- The liquid inside a vacuole is known as cell sap, which primarily consists of water, inorganic ions, organic molecules, and waste products.

**Hint**: Focus on the idea that cell sap is a mixture, not just water.

4. **Function of Vacuole**:
- The main functions of vacuoles include storing waste products, maintaining turgor pressure (which helps keep the plant cell rigid), and isolating harmful materials from the rest of the cell.

**Hint**: Consider how vacuoles help in keeping the cell healthy and functional by managing waste.

5. **Analyzing the Options**:
- The options provided are:
1. Lacks membrane and contains water and excretory substances.
2. Membrane-bound and contains storage proteins and lipids.
3. Membrane-bound and contains water and excretory substances.
4. Lacks membrane and contains air.

- Evaluating these options:
- Option 1 is incorrect because vacuoles are membrane-bound.
- Option 2 is incorrect because vacuoles do not primarily store proteins and lipids.
- Option 3 is correct as it accurately describes vacuoles as membrane-bound and containing water and excretory substances.
- Option 4 is incorrect because vacuoles do not lack membranes.

**Hint**: When evaluating options, always refer back to the definitions and functions you’ve learned.

6. **Conclusion**:
- The correct answer is Option 3: "It is membrane-bound and contains water and excretory substances."

**Hint**: Summarize what you’ve learned to reinforce the correct answer.