Diffusion is the movement of a molecule from an area of higher concentration to an area of lower concentration.

True or False?

Choice A rationale: Starch solution is not a protein solution, but a carbohydrate solution. Starch is a polysaccharide, which is a polymer of glucose molecules. Starch does not contain peptide bonds, which are the bonds that link amino acids in proteins. Therefore, starch solution would not react with the biuret reagent and would not produce a violet color.

Choice B rationale: Olive oil is not a protein solution, but a lipid solution. Olive oil is mainly composed of triglycerides, which are esters of glycerol and fatty acids. Olive oil does not contain peptide bonds, which are the bonds that link amino acids in proteins. Therefore, olive oil would not react with the biuret reagent and would not produce a violet color.

Choice C rationale: Albumin solution is a protein solution. Albumin is a globular protein that is found in blood plasma and egg white. Albumin contains many peptide bonds, which are the bonds that link amino acids in proteins. Therefore, albumin solution would react with the biuret reagent and would produce a violet color.

Choice D rationale: Distilled water is not a protein solution, but a pure solvent. Distilled water is water that has been purified by boiling and condensing. Distilled water does not contain any solutes, such as proteins, carbohydrates, or lipids. Therefore, distilled water would not react with the biuret reagent and would not produce a violet color.

Choice E rationale: Glucose solution is not a protein solution, but a carbohydrate solution. Glucose is a monosaccharide, which is a simple sugar. Glucose does not contain peptide bonds, which are the bonds that link amino acids in proteins. Therefore, glucose solution would not react with the biuret reagent and would not produce a violet color.

Choice A rationale: The cell membrane did not change at all because of the protection of the cell wall is incorrect because the cell wall does not prevent the movement of water across the cell membrane. The cell wall only provides mechanical support and prevents the cell from bursting in a hypotonic solution.

Choice B rationale: The cells burst because the solution was hypotonic is incorrect because the solution was hypertonic, not hypotonic. A hypertonic solution has a lower concentration of water than the cell, so water moves out of the cell and into the solution by osmosis, causing the cell to shrink.

Choice C rationale: The cell membrane shrank, but the central vacuole remained full is incorrect because the central vacuole also loses water in a hypertonic solution. The central vacuole is a large organelle that stores water and other substances in the plant cell. When water leaves the cell, the central vacuole shrinks and the cell loses its turgor pressure.

Choice D rationale: The cell membrane shrank away from the cell wall because the solution was hypertonic is correct because this is what happens when a plant cell is placed in a hypertonic solution. The cell membrane and the cytoplasm contract and pull away from the cell wall, creating a gap between them. This is called plasmolysis and it can damage the cell.

Choice E rationale: The cell became turgid is incorrect because the cell becomes turgid in a hypotonic solution, not a hypertonic one. A hypotonic solution has a higher concentration of water than the cell, so water moves into the cell and out of the solution by osmosis, causing the cell to swell and press against the cell wall. This is called turgor and it helps the cell maintain its shape and rigidity.