1.a) potential to lowwater potential. This action
1.a) Bulk movement is the overall movement of a fluid. The molecules allmove in the same direction. Diffusion however is the random movement ofmolecules which usually results in a fairly even distribution. In otherwords the movement is not guaranteed to move in one direction but theprobability that it will move in the lower gradient is greater. Osmosis issimilar to diffusion but is differentiated by the membrane’s behavior.
Thecell membrane does allow water to move from higher to lower concentrationsbut does not allow solutes do that. b) Water potential is the capacity ofwater to move to a from a region where there is high water potential to lowwater potential. This action happens without the affect of outside forces.
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When outside actions due occur and they give water a high potential energythan the water will move to the region where less potential energy is. Hydrostatic pressure is the pressure required to stop water the movement ofwater. This is a method of measurement. The osmotic potential is themeasure of tendency of water to move through a membrane which contains asolution. This occurs when a cell does not allow a hypertonic solution toleave the cell membrane.
The cell begins to increase with water but thecell membrane can not release the solution and thus the water potentialwithin the cell increases. This causes the water to no longer enter thecell. c) Hypotonic is less solute to a certain amount of water. Hypertonicis more solute to a certain amount of water. Isotonic is the equal amountof solutes in two different solutions. d) Endocytosis is the inward bulgecauses by incoming molecules. Exocytosis is the expelling of a materialoutside a cell.
e) Phagocytosis is the process where the cell obtainssolid matter. This is different from the pinocytosis where the cellobtains liquid matter. These both are endocytic processes. Receptor-mediated endocytosis is the process where there are interactionsbetween a material and receptor sites on the cell.
In this process thecell accepts the material if it matches with the receptor sites. f) Coatedpits are areas which peripheral proteins indent the membrane. This iswhere the vesicles for certain materials are formed. The vesicle which isformed is called the coated vesicle.g) Plasmodesmata are the linkswhich hold two adjacent cells together.
Gap junctions are the channelswhich allow materials to flow between cells. 2. The concentration gradient is the difference in the density of amaterial from one region to another region. The concentration gradientaffects diffusion by allowing the substance to flow from high concentrationto low concentration. The concentration gradient affects osmosis by thesame manner it does in diffusion. The cell does not allow the solution toexit the cell when water is entering. This keeps the solution in the cellmaking the concentration high and thus no further penetration of water.
4. Diffusion is more rapid in gases because they are less dense thanliquids. They repel each other more resulting in faster diffusion. Diffusion is greater at higher temperatures because of the greater kineticenergy among the molecules. They push each other more making them lessdense.
5. The concentration of the solute is 1%. This happens because a 1% sugarsolution is isotonic with that of the 1% sugar solution in the tubes.
The2% sugar solution was increased because the substance was hypertonic. Themembrane did not allow the hypertonic solution to exit because the pressurefrom the hypotonic solution was forcing water in. This later reached anequilibrium when the hypertonic solution was gaining water potential andthe water stopped rising. The vice versa happened in the distilled watersolution.