Question

Solution concentration can be described in terms of tonicity. A solution is one that has a greater concentration of solute outside the cell and therefore a lower concentration. Water will leave the cell, to the outside environment. This is one reason why organisms that live in fresh water cannot survive in salt water, the ocean. Water will leave the organism’s cells and eventually the cells will undergo plasmolysis and the organisms will die. An solution is a balanced solution. That is, the solution concentration is balanced with the solution inside the cell. Finally, when a cell is surrounded by a solution, concentration of solute is greater inside the cell, concentration of water greater outside. Water moves into the cell and the cell swells. If enough water enters, the cell can burst

Answer 1

You are describing the three main types of tonic solutions in relation to cell biology: hypertonic, isotonic, and hypotonic solutions. Here’s a breakdown of these concepts:

1. Hypertonic Solution: This is a solution with a higher concentration of solute compared to the inside of the cell. When a cell is placed in a hypertonic solution, water will move out of the cell to the area of higher solute concentration (outside the cell) in an attempt to balance the solute concentrations. This loss of water can lead to plasma membrane detachment from the cell wall (in plant cells) and shrinkage of the cell, a process known as plasmolysis. Organisms like freshwater fish cannot survive in hypertonic environments (like salt water) because their cells will lose water and eventually die.

2. Isotonic Solution: In an isotonic solution, the concentration of solutes is equal inside and outside the cell. As a result, there is no net movement of water into or out of the cell. This state of balance is crucial for maintaining cell structure and function. Cells thrive in isotonic conditions, as they maintain their shape and do not experience stress from osmotic pressure.

3. Hypotonic Solution: A hypotonic solution has a lower concentration of solute compared to the inside of the cell. In this scenario, water moves into the cell because the concentration of water is higher outside than inside. When water enters the cell, it can cause the cell to swell. If the influx of water is substantial, the cell may eventually burst in a process known as lysis. While animal cells can burst in hypotonic solutions, plant cells have cell walls that provide structural support, which helps prevent lysis.

Overall, the concept of tonicity is vital for understanding how cells interact with their environments, particularly in terms of water movement and solute concentration, which is essential for homeostasis.