How do dissolved solutes contribute to the water potential of the cell?
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Water potential is\nψ=ψs+ψp where ψs is the contribution of the solutes (osmotic pressure) and ψp the pressure on that side of the membrane.\n\nψs is always negative, so dissolving solutes lowers the water potential. When there are no cell walls the pressure on both sides of the membrane is the same and thus water potential is equal to ψs.\n\nFor plant or bacterial cells which have walls internal pressure can build up so you have to take it into account if you want to see whether water will enter the cells.
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Answer = A\n\nA larger cell (answer B) can hold more charged particles, but a small cell with 5 charged particles will have the same potential as a large cell with 5 charged particles!\n\n(C) and (D) relate to how quickly the cell can re-creat the resting membrane potential once, say, an action potential has passed through the nerve.
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Keep the cell contents bound together,exchange gases and excreta,Semi permeable entry i.e. it protects the cell by allowing only some Substances to enter the cell, maintains the shape of the cell and helps in transfer of water from cell wall as it has hydrophilic proteins in plants
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Ionophores- They havea negatively charged channel that allows the solute to enter\n\nFacilitated diffusion- Essentially they capture a solute and tug it into the cell.\n\nactive transport- i believe they look similarly to proteins that facilitate diffusion
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1-For terminal oxidation of Water and release of oxygen.\n2-As a solvent for many metabolic reactions.\n3-For cellular osmotic pressure.\n4-For transpiration.\n5-For seed imbibition.
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http://www.biologyreference.com/Ve-Z/Water-Movement-in-Plants.html\n\nThe Cohesion-Tension Theory\nThe major mechanism for long-distance water transport is described by the cohesion-tension theory, whereby the driving force of transport is transpiration, that is, the evaporation of water from the leaf surfaces. Water molecules cohere (stick together), and are pulled up the plant by the tension, or pulling force, exerted by evaporation at the leaf surface.\n\nWater will always move toward a site with lower water potential, which is a measure of the chemical free energy of water. By definition, pure water has a water potential of 0 MegaPascals (MPa). In contrast, at 20 percent relative humidity, the water potential of the atmosphere is -500 MPa. This difference signifies that water will tend to evaporate into the atmosphere. The water within plants also has a negative potential, indicating water will tend to evaporate into the air from the leaf. The leaves of crop plants often function at -1 MPa, and some desert plants can tolerate leaf water potentials as low as -10 MPa. The water in plants can exist at such low water potentials due to the cohesive forces of water molecules. The chemical structure of water molecules is such that they cohere very strongly. By the cohesion-tension theory, when sunlight strikes a leaf, the resultant evaporation first causes a drop in leaf water potential. This causes water to move from stem to leaf, lowering the water potential in the stem, which in turn causes water to move from root to stem, and soil to root. This serves to pull water up through the xylem tissue of the plant.\nFrom Root to Leaf\nPlants have root hairs and often mycorrhizal fungi at the root surface, both of which serve to filter the soil water as it enters the plant. Mycorrhizae are symbiotic associations between plant roots and fungi. The root cells and mycorrhizal fungi both actively uptake certain mineral nutrients. Mycorrhizae can be particularly important for the uptake of phosphate. The active uptake of minerals by living cells of the root and the subsequent transfer of minerals to the xylem can result in positive root pressures, with water potentials above 0 MPa. This occurs only under certain conditions, such as at night or during rainstorms, when water loss from the leaves is minimal. Such positive root pressures disappear with the onset of leaf transpiration.\n\nWater molecules move from the soil into living cells of the root, and eventually into the transport cells of the xylem, known as tracheids and vessels. These xylem cells are dead and hollow, allowing rapid water transport. They also have hardened cell walls to help them resist the tendency to collapse as water is sucked through them. Both tracheids and vessels \n\n \nA drop of guttation, water extruded by a plant's root pressure, on a blade of grass. have pits on the sides of their walls, which include porous areas for side-to-side transport. Unlike tracheids, a vessel is composed of many cells stacked end to end, with perforations between cells, allowing for more efficient transport.\n\nThe long-distance transport of the water molecule occurs first within the xylem cells of the root, then the xylem of the stem and branch, and then into the xylem of a leaf midrib and vein. Driven by transpiration, the water molecule is pulled from the nonliving tracheids and vessels of the xylem in the living cells of the leaf mesophyll (middle layer) and to the surface of mesophyll cell walls. The water molecule then evaporates into a leaf inter-cellular air space and finally out of a stomatal pore and into the atmosphere. Though photosynthetic action consumes some water, only a small fraction of the water that travels through the plant is used directly for the photo-synthetic reaction, which occurs in leaf mesophyll cells. Instead, most water is lost by transpiration through the stomates.\nThe Role of Stomates\nLeaves of land plants are covered with a waxy cuticle that pr
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Water travels through a network of 'veins' through out the plant. The cells are re-hydrated which causes them to expand like a balloon. Once the cells are all filled to capacity, they rest on each other. The cell membranes contain cellulose that helps them stand erect when fully hydrated.
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Surface Tension = An attractive force between water molecules called hydrogen bonding.
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Solute is anything tht is disolved in the liquid. If there was no solute, all you'd have is distilled water.
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If you REALLY want to know about this take a look at my source.  But I can summarize it for you.  Think of water as something that assists chemical reactions in a cell.  Without it the cell is powerless.\n\nWater also acts as a transportation mechanism to "take out the trash", as well as "bring in the goods."  As far as energy goes, this is something that is driven by the Kreb Cycle in the Mitochondria of a cell. This process actually produces water.
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solute is the substance that dissolves into the solvent. i.e. in salt and water, salt would be the solute and water would be the solvent.
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When water enters the cell..it must be regulated or the cell will...em...explode...these vacuoles help the paramecium to send out extra water...
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Capillary forces and water potential.  The water potential is the tendency of water to move from one place to another, due to evaporation or stuff dissolved in the water.
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The hydrostatic pressure is generated by the pumping force of the heart. It pushes water out of the capillaries.\n\nThe water potential is created due to the inability of large solutes to pass through the capillary walls. This buildup of solutes induces osmosis. The water passes from a high concentration (of water) to a low concentration in an attempt to reach an equilibrium. This draws water back into the vessels. Because the blood in the capillaries is constantly flowing, equilibrium is never reached.\n\nThe balance between the two forces is different at different points in the capillaries. At the arterial end of the vessel, the hydrostatic pressure is greater than the water potential, so the net movement (see net flux) favors water and other solutes being passed into the tissue fluid. At the venous end, the water potential is greater, so the net movement favours substances being passed back into the capillary. This difference is created by the direction of the flow of blood, and the imbalance in solutes created by the net movement of water favoring the tissue fluid
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Because of osmosis (the diffusion of water through a membrane) the water will move from the higher concentration of water to the lower concentration of water. (From the solution with less sugar, to the solution with more sugar, because it has less water in it with the sugar taking up the space.)
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it is the potassium pump mechanism which pumps k+ ions actively ind other ions like cl-, malate ions enter passively and thereby increasing the solute potential of the guard cell and increasing the turgidity\n\nbut the cellulose micro fibrils do not allow radial expansion of the cell\n\ntherefor the guard cell's outer wall expand but due to thickening of inner wall it can't expand!!\n\nthere for along with the outer thin wall, the inner wall is also being pulled out!!!\n\ntherefor increasing the width of the stomatal pore and causing stomatal opening!!!!!!!!!!!!\n\nalso he wise versa
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Osmosis is the movement of water thru a semi-permeable membrane.  Water would move from an environment of low solute concentration to an environment of high solute concentration.  Only the water molecules move, not the solutes, because the membrane is only permeable to water.  The reason that water molecules move is becaues things like to be in equilibrium.  Because the side of higher solute concentration has more matters relative to the whole system, that's why it attracts water there too.  Another way you can think about is that the side where there are more solutes provide more surface areas for the water molecules to have more contact with (more weak interactions between the water and the solutes), therefore water want to go there.  So water likes to go to where there isn't a lot of water.  (you might ask then why wouldn't the solutes move to the side that has less solute.  They won't, because your membrane is only permeable to water.)  So if you are solving problems like these, must pay close attention to the membrane permeability.\n\nDiffusion is a similar concepts.  Things like to go where there are less of them.  In the above example, because the environment has a lot of solute, BUT little water, that's why water goes to that size.  Things tend to go toward disorder (entropy), so more matters means more disorder.\n\nActive transport-this means that the movement of matters from one side to the other can only be possible if there are help, such as protein pumps.  I guess the best example is the sodium-potassium pumps.  Energy is used (main energy source is ATP) so that sodium ions and potassium ions are pumped into and out of the cell, respectively.  But again, this is also based on the concept that things tend to go to the side that there are less of them.\n\nHope that helps.  If you find some terms confusing, just go to wiki or answers.com and search for them.\nGoodluck!