To demonstrate that plasmolysis occurs in living cells
Answers
Plasmolysis is when plant cells lose water after being placed in a solution that has a higher concentration of solutes than the cell does. This is known as a hypertonic solution. Water flows out of the cells and into the surrounding fluid due to osmosis. This causes the protoplasm, all the material on the inside of the cell, to shrink away from the cell wall. Severe water loss that leads to the collapse of the cell wall can result in cell death. Since osmosis is a process that requires no energy on the part of the cell and cannot be controlled, cells cannot stop plasmolysis from taking place.
Plasmolysis and Osmosis
Osmosis is responsible for the occurrence of plasmolysis. Osmosis is a special type of diffusion that occurs when water flows into or out of a membrane such as a cell’s plasma membrane. It occurs based on the type of solution that a cell is in. A solution is a mixture that contains a fluid, or solvent (usually water), and a solute that is dissolved in the solvent. When a cell is placed into a hypertonic solution, there is a higher concentration of solutes outside the cell, so water flows out of the cell to balance the concentration on both sides of the membrane. Since plasmolysis is the loss of water from a cell, it occurs when a cell is in a hypertonic solution. Conversely, when a cell is placed into a hypotonic solution, there is a lower solute concentration outside the cell than inside, and water rushes into the cell. In an isotonic solution, solute concentrations are the same on both sides, so there is no net gain or loss of water.
Plant cells fare best in hypotonic solutions. This is because when plant cells are full of water, they push against each other to form the basic support structure for the plant and allow it to stand upright. Plant calls full of water are known as turgid cells; they exert turgor pressure on each other. The cells’ rigid cell wall keeps them from bursting. Unlike plant cells, animal cells do not have a cell wall in addition to their cell membrane. When animal cells are placed in a hypotonic solution and too much water rushes in, they will lyse, or burst. They fare best in isotonic solutions instead.
Since plasmolysis is the loss of water from a cell, it occurs when a cell is in a hypertonic solution. Conversely, when a cell is placed into a hypotonic solution, there is a lower solute concentration outside the cell than inside, and water rushes into the cell. ... Plant cells fare best in hypotonic solutions.