student is investigating the process of osmosis. She fills a medicine dropper with red blood cells. Next, she creates a saline solution that is isotonic to the red blood cells. What will most likely happen to the red blood cells after they are placed in the solution?
a
Water will enter and exit the cells at a steady rate and their sizes will remain the same.
b
Water will neither enter or exit the cells and their sizes will remain the same.
c
Water will enter the cells and cause them to grow in size.
d
Water will exit the cells and cause them to shrink in size.
a
Water will enter and exit the cells at a steady rate and their sizes will remain the same.
b
Water will neither enter or exit the cells and their sizes will remain the same.
The correct answer is b) Water will neither enter nor exit the cells, and their sizes will remain the same.
To understand why, let's first understand the concept of osmosis. Osmosis is the movement of water molecules through a selectively permeable membrane, such as the cell membrane, from an area of high water concentration to an area of low water concentration. The purpose of osmosis is to maintain a balance of water and solutes on both sides of the membrane.
When a cell is placed in a solution, three possible scenarios can occur: hypertonic, hypotonic, or isotonic.
In a hypertonic solution, the solute concentration outside the cell is higher than inside the cell. As a result, water molecules move out of the cell, causing it to shrink in size.
In a hypotonic solution, the solute concentration outside the cell is lower than inside the cell. This causes water molecules to move into the cell, making it swell and potentially burst.
In an isotonic solution, the solute concentration is the same both inside and outside the cell. This means there is no net movement of water molecules, resulting in no change in the size of the cell.
In the given scenario, the student created a saline solution that is isotonic to the red blood cells. This means that the concentration of solutes in the saline solution is the same as the concentration inside the red blood cells. Therefore, there will be no net movement of water molecules into or out of the cells, and their sizes will remain the same.
So, option b) Water will neither enter nor exit the cells, and their sizes will remain the same is the correct answer.