What prevents a plant cell from bursting in a hypotonic solution?

Choice A rationale: Albumin solution is not a negative control, but a positive control for the test for protein. Albumin is a type of protein that reacts with the biuret reagent and produces a violet color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.

Choice B rationale: Starch solution is not a negative control, but a positive control for the test for starch. Starch is a type of carbohydrate that reacts with the iodine solution and produces a blue-black color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.

Choice C rationale: Glucose solution is not a negative control, but a positive control for the test for sugar. Glucose is a type of sugar that reacts with the Benedict's solution and produces a red-orange color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.

Choice D rationale: Olive oil is not a negative control, but a positive control for the test for lipids. Olive oil is a type of lipid that reacts with the Sudan III solution and produces a red color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.

Choice E rationale: Distilled water is a negative control for the tests for protein, lipids, sugars, and starch. Distilled water is a pure solvent that does not contain any of these substances. It does not react with any of the reagents and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.

Choice A rationale: The solute concentration of the cytoplasm inside the cell is correct because tonicity is a measure of how the solution affects the movement of water across the cell membrane by osmosis. Osmosis is the process by which water moves from a region of high water concentration to a region of low water concentration. The water concentration of a solution is determined by the solute concentration of the solution. The higher the solute concentration, the lower the water concentration, and vice versa. Therefore, tonicity compares the solute concentration of the solution outside the cell to the solute concentration of the cytoplasm inside the cell.

Choice B rationale: The permeability of the cell membrane is incorrect because permeability is a property of the cell membrane that determines how easily molecules can pass through it, not a measure of tonicity. The cell membrane is selectively permeable, meaning that it allows some molecules to cross, but not others. The cell membrane is permeable to water, but not to most solutes.

Choice C rationale: The swelling of the cell is incorrect because swelling is a result of tonicity, not a measure of it. Swelling occurs when a cell is placed in a hypotonic solution, which has a higher concentration of water and lower concentration of solute than the cell. In a hypotonic solution, water moves into the cell and out of the solution by osmosis, causing the cell to swell.

Choice D rationale: The number of cell fragments inside the cell is incorrect because cell fragments are pieces of broken cells that have no relation to tonicity. Cell fragments can be produced by mechanical damage, apoptosis, or necrosis, but they do not affect the solute concentration of the cytoplasm or the solution.

Choice E rationale: The presence of a cell wall is incorrect because the cell wall is a structure that surrounds the cell membrane in some cells, such as plant cells, but it does not affect tonicity. The cell wall is made of cellulose, a polysaccharide that is resistant to water. The cell wall provides mechanical support and prevents the cell from bursting in a hypotonic solution, but it does not change the solute concentration of the cytoplasm or the solution.