Investigation of Water Potential in a Root Vegetable
Investigation of Water Potential in a Root Vegetable
Introduction
Background Information:
Osmosis is the passage of water from a region of high water potential to a region of low water potential, down a water potential gradient through a semi-permeable membrane. If a plant cell, or an item with similar properties is put in water, three different things can happen: • If the surrounding area has a higher water potential, the cell will increase in mass through osmosis. The cell will become turgid. • If the surrounding area has a lower water potential, the cell will decrease in mass through osmosis. The cell will become flaccid. (If you look at the cells under a microscope, you will see the plasma membrane + cell contents have pulled away from the cell wall: They have been plasmolysed) • If the medium is exactly the same water potential as the cell there will be no net movement. (Water crosses the cell membrane but the amount going in is the same as the amount coming out, so there is no net movement, When the cell is in this state between turgidity and flaccidity, It’s called Incipient Plasmolysis.
Osmosis is a form of passive transport, passive transport doesn’t use energy, the molecules go down a concentration gradient.
Active transport is the opposite it uses ATPase for energy, and molecules move against a concentration gradient.
Prediction: When the potato cylinder is placed in a high water potential sucrose solution I think it will increase in mass, and length. This is because the solution has a higher water potential than the cells in the cylinder, water molecules will travel from a high water potential (The solution) to a low water potential (The potato cylinder) through a semi-permeable membrane by osmosis. More molecules will enter the cell then leave it, so the potato cylinder will swell, as the cells become turgid. The contents of the cell in this state of turgidity push against the cell wall, which causes
Introduction
Background Information:
Osmosis is the passage of water from a region of high water potential to a region of low water potential, down a water potential gradient through a semi-permeable membrane. If a plant cell, or an item with similar properties is put in water, three different things can happen: • If the surrounding area has a higher water potential, the cell will increase in mass through osmosis. The cell will become turgid. • If the surrounding area has a lower water potential, the cell will decrease in mass through osmosis. The cell will become flaccid. (If you look at the cells under a microscope, you will see the plasma membrane + cell contents have pulled away from the cell wall: They have been plasmolysed) • If the medium is exactly the same water potential as the cell there will be no net movement. (Water crosses the cell membrane but the amount going in is the same as the amount coming out, so there is no net movement, When the cell is in this state between turgidity and flaccidity, It’s called Incipient Plasmolysis.
Osmosis is a form of passive transport, passive transport doesn’t use energy, the molecules go down a concentration gradient.
Active transport is the opposite it uses ATPase for energy, and molecules move against a concentration gradient.
Prediction: When the potato cylinder is placed in a high water potential sucrose solution I think it will increase in mass, and length. This is because the solution has a higher water potential than the cells in the cylinder, water molecules will travel from a high water potential (The solution) to a low water potential (The potato cylinder) through a semi-permeable membrane by osmosis. More molecules will enter the cell then leave it, so the potato cylinder will swell, as the cells become turgid. The contents of the cell in this state of turgidity push against the cell wall, which causes