The cell shrinks in across the B. cell membrane. Therefore ,B. cell membrane is correct.
In this case, the beaker has a higher salt concentration than the cell, so the water inside the cell will move out to the beaker in an attempt to equalize the salt concentrations on both sides of the membrane.
This loss of water causes the cell to shrink.
Another way to think about it is that the salt concentration in the beaker is higher than the salt concentration in the cell, so the water molecules in the cell are drawn to the beaker because they are trying to dilute the salt concentration in the beaker.
Osmosis is a very important process for cells. It allows cells to maintain their water balance and to take in nutrients and other essential molecules.
However, if a cell is placed in a hypertonic solution (a solution with a higher solute concentration than the cell), the cell will lose water and shrink.
This can be harmful or even deadly to the cell.
The cell on the left is in a hypotonic solution (a solution with a lower solute concentration than the cell), so water moves into the cell and the cell swells.
The cell in the middle is in an isotonic solution (a solution with the same solute concentration as the cell), so there is no net movement of water across the cell membrane.
The cell on the right is in a hypertonic solution, so water moves out of the cell and the cell shrinks.
Question
A cell with a 10% salt concentration is placed into a beaker that contains a 20% salt concentration. The cell shrinks, as shown in the diagram below.
Which part of the cell controls the movement of substances?
A. mitochondria
B. cell membrane
C. chloroplast
D. nucleus