2. What do you predict might happen to the cells of a fish that is accustomed to living in fresh water if the fish were placed in salt water? Explain your answer.
If a fish that is accustomed to living in fresh water is placed in salt water, the cells of the fish may undergo dehydration and potential damage. This is because salt water has a higher concentration of salt or solutes compared to fresh water.
In freshwater, fish cells have a higher concentration of solutes compared to the surrounding water. This creates a concentration gradient that allows water to enter the cells through osmosis. Osmosis is the movement of water molecules from an area of lower solute concentration (inside the cells) to an area of higher solute concentration (the freshwater environment). Thus, the fish can maintain its water balance by continuously absorbing water through its gills and other permeable surfaces.
However, in saltwater, the reverse occurs. The saltwater has a higher concentration of solutes compared to the fish's cells. This creates a concentration gradient that leads to the movement of water molecules from the inside of the fish's cells to the surrounding saltwater. The fish's cells would lose water through osmosis to the hypertonic (higher solute concentration) environment of saltwater.
As a result, the fish's cells would start to dehydrate, leading to physiological stress and potentially cell damage. This dehydration can disrupt cellular processes and impair the functioning of vital organs. Additionally, the loss of water can also lead to imbalances in electrolytes within the fish's body, affecting its overall homeostasis and potentially leading to further complications.
In response to being placed in saltwater, the fish may try to compensate for the water loss by increasing its drinking behavior or secreting excess salt through special cells in its gills. However, these mechanisms may not entirely offset the dehydration caused by the saltwater, and the fish may still experience negative effects on its cellular health and overall well-being.