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How does humidity affect the water potential?
Humidity affects water potential by influencing the concentration of water molecules in the air. High humidity reduces the water potential gradient between a plant and its surrounding environment, making it harder for the plant to take up water through osmosis. Low humidity, on the other hand, increases the water potential gradient, promoting water uptake by the plant.
How does water leave a cell when placed in salt water?
osmosis, which is diffusion of water across a membrane from an area with lower solute concentration to an area of higher solute concentration to equalize the concentration on both sides of the membrane.
What is the new water potential of a plant cell of water potential 500kPa after immerse into pure water?
Water potential is the potential energy of water in a system (eg a solution or a cell) compared with pure water under the same conditions. The value of the water potential depends mainly on two factors: 1) The presence of dissolved solutes. Solutes dissolved in the water reduce the energy of the water molecules, and so lower the water potential. This happens because the solute molecules attract the water molecules and reduce their movement. The component of water potential due to solutes is called the solute potential of the solution. 2) The presence of an excess pressure, above that of normal atmospheric pressure. Pressure increases the movement of the water molecules and so increases their energy, thus increasing the water potential. The component of water potential due to pressure is called the pressure potential of the solution. The total water potential of a solution is the sum of the solute potential and pressure potential water potential = solute potential + pressure potential The pressure potential can be positive or negative. An additional pressure on the solution will be positive and increase the pressure potential. If the solution is subject to a reduced pressure (a negative pressure or suction) the pressure potential will be negative and will reduce the water potential. The solute potential is always negative and so always reduces the water potential. Pure water is given a water potential of zero (similar to the way in which the freezing point of water is given a value of 0o Celsius). So anything which reduces the energy of the water molecules (such as dissolving a solute) will reduce the water potential to below zero, and so will be negative. The movement of water depends on the difference in water potential between two systems eg two adjacent cells, or a cell and the surrounding solution. This difference is called the water potential gradient. Water will always move from the higher to the lower water potential ie down the water potential gradient. In osmosis, the two solutions involved are often at atmospheric pressure. In this case it is only the difference in solute concentration which determines the direction of water movement. Water moves from the dilute solution to the concentrated solution. The concentrated solution has a higher concentration of dissolved particles, and so has a lower solute potential than the dilute solution. Since the pressure potential is zero (no excess pressure), the water potential is equal to the solute potential. Water will therefore move from the higher water potential (ie the dilute solution) to the lower water potential (ie the more concentrated solution), down the water potential gradient. It is possible for the pressure potential to counteract the solute potential. For example, if a solute (eg salt) is added to pure water, the water potential will be reduced to a negative value. If the solution is then put under extra pressure eg in a syringe, the positive pressure potential can raise the total water potential above zero ie give it a positive value. This happens especially in plant cells, where the cell wall prevents an increase in volume of the cell. So if water enters by osmosis the extra water molecules cause the pressure inside the cell to increase. This intracellular pressure in a plant cell is called the turgor pressure. For more information see: http://en.wikipedia.org/wiki/Water_potential http://www.colorado.edu/eeb/courses/4140bowman/lectures/4140-07.html http://www.phschool.com/science/biology_place/labbench/lab1/watpot.html
Is concentration gradient a form of potential energy?
Yes, a concentration gradient represents potential energy in the form of chemical potential energy. This energy arises from the difference in concentration of a substance across a membrane, and it can be used to drive processes like diffusion or active transport.
What are the two things needed for osmosis to take place?
Partially permeable membrane(visking tubing) and water
How does water leave a cell when in salt water?
Water moves according to an concentration gradient. Water potential gradient between two places
What is potential gradient?
The rate of change of potential with respect to distance is called potential gradient. its unit is volt per meter or newton/coulomb.
What is the definition of electric gradient?
the rate of change of maximum value of potential with respect to distance is known as potential gradient
How can osmosis be used to transfer energy?
It can't. As osmosis is the natural movement of water down a water potential gradient, it requires no energy.
Is potential gradient vector or scalar?
The potential gradient is a vector quantity. It represents the rate of change of the scalar electric potential with respect to position in space.
How does humidity affect the water potential?
Humidity affects water potential by influencing the concentration of water molecules in the air. High humidity reduces the water potential gradient between a plant and its surrounding environment, making it harder for the plant to take up water through osmosis. Low humidity, on the other hand, increases the water potential gradient, promoting water uptake by the plant.
What features of water allows plants to draw liquid water up from their roots?
hydrogen bonding of the water and water potential gradient between the soil and the roots. the process is driven by transpiration of plants
When does osmotic equilibrium occur?
When the water potential gradient evens out, so that the water potential on eithersides of the partially permeable membrane is equal. Also, when something is placed in an isotonic solution ( a solution with the same waterpotential as the organism contains)
What feature or property of water allows plants to draw liquid from their roots?
hydrogen bonding of the water and water potential gradient between the soil and the roots. the process is driven by transpiration of plants
Why electric field is negative gradient of electric potential?
The electric field is the negative gradient of the electric potential because it points in the direction of steepest decrease in potential. This relationship is based on the definition of potential energy as work done per unit charge. Negative gradient signifies the direction of decreasing potential with respect to position in space.
How do you define voltage gradient?
A voltage gradient or, more accurately, potential gradient, is the change in electric potential measured between a point of high potential and a point of low potential. It is normally measured with respect to one or other of these two points.A practical example of a potential gradient can be demonstrated by connecting a variable resistor as a potentiometer. If an external voltage is applied across opposite ends of the potentiometer, then a potential gradient can be observed by connecting a voltmeter between one end of the potentiometer and its wiper terminal, and varying the position of the wiper. As the wiper is moved from one end of the potentiometer to the other, the potential will be seen to fall towards zero.
Do electron moves up or fall down a potential gradient?
The potential gradient gives the electric field intensity E at point in electric field which is directed from high to low potential. An electron being a negative charge particle therefore will tend to move from low potential to high potential, hence will move up the electric field
