Effect of Different Concentrations of Salt on Potato Cell Mass
Aim
To investigate the effects of increasing salinity on potato cell mass.
Background Information
This experiment is based upon osmosis. Osmosis can be defined as the net movement of water molecules from a region with high concentration to a region with low concentration. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. This process will take place until it reaches the equilibrium state, which means that the water molecules will be distributed until there are no regions with high or low concentrations.
Plant cells have a protective layer—called cell wall—covering its cell membrane. During the intake of water by osmosis they start to swell. This cell wall will help prevent it from bursting. The plant cells become "turgid"—which means they become swollen and hard—when they are put in dilute solutions. The pressure inside the cell rises and eventually the internal pressure of the cell is so high that no more water can enter the cell. In contrast, when plant cells are placed in concentrated sugar solutions, they lose water by osmosis and become "flaccid", which is the opposite of “turgid”. The contents of the potato cells will then decrease in size and repel from the cell wall.
Hypothesis
Based on this prior knowledge, I predict that when the potato is placed in distilled water the potato mass will increase. Distilled water is pure, therefore it will have a weaker concentration than the potato, and the water molecules travel through a partially permeable membrane by osmosis.
In a case where the potato is in a solution with a high concentration of salt, the potato mass will decrease because the potato is less concentrated than the salt solution, and the water will move through the partially permeable membrane into the stronger solution. On the other hand, if the potato mass remains the same after the
To investigate the effects of increasing salinity on potato cell mass.
Background Information
This experiment is based upon osmosis. Osmosis can be defined as the net movement of water molecules from a region with high concentration to a region with low concentration. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. This process will take place until it reaches the equilibrium state, which means that the water molecules will be distributed until there are no regions with high or low concentrations.
Plant cells have a protective layer—called cell wall—covering its cell membrane. During the intake of water by osmosis they start to swell. This cell wall will help prevent it from bursting. The plant cells become "turgid"—which means they become swollen and hard—when they are put in dilute solutions. The pressure inside the cell rises and eventually the internal pressure of the cell is so high that no more water can enter the cell. In contrast, when plant cells are placed in concentrated sugar solutions, they lose water by osmosis and become "flaccid", which is the opposite of “turgid”. The contents of the potato cells will then decrease in size and repel from the cell wall.
Hypothesis
Based on this prior knowledge, I predict that when the potato is placed in distilled water the potato mass will increase. Distilled water is pure, therefore it will have a weaker concentration than the potato, and the water molecules travel through a partially permeable membrane by osmosis.
In a case where the potato is in a solution with a high concentration of salt, the potato mass will decrease because the potato is less concentrated than the salt solution, and the water will move through the partially permeable membrane into the stronger solution. On the other hand, if the potato mass remains the same after the
Bibliography: 1. Clegg, CJ. (2007). Biology for the IB Diploma. London, Hodder Murray. 2. Walpole, Brend; Merson-Davies, Ashby; Dann, Leighton (2011). Biology for the IB Diploma. Oxford, Cambridge University Press. 3. "The Effects of Glucose Concentration on Osmosis in Potato Cells." 123HelpMe.com. Retrieved 22 September, 2013, from http://www.123helpme.com/view.asp?id=148152