РефератыИностранный языкDiDiffusion And Osmosis Essay Research Paper 1

Diffusion And Osmosis Essay Research Paper 1

Diffusion And Osmosis Essay, Research Paper


1. a) Bulk movement is the overall movement of a fluid. The molecules all


move in the same direction. Diffusion however is the random movement of


molecules which usually results in a fairly even distribution. In other


words the movement is not guaranteed to move in one direction but the


probability that it will move in the lower gradient is greater. Osmosis is


similar to diffusion but is differentiated by the membrane’s behavior. The


cell membrane does allow water to move from higher to lower concentrations


but does not allow solutes do that. b) Water potential is the capacity of


water to move to a from a region where there is high water potential to low


water potential. This action happens without the affect of outside forces.


When outside actions due occur and they give water a high potential energy


than the water will move to the region where less potential energy is.


Hydrostatic pressure is the pressure required to stop water the movement of


water. This is a method of measurement. The osmotic potential is the


measure of tendency of water to move through a membrane which contains a


solution. This occurs when a cell does not allow a hypertonic solution to


leave the cell membrane. The cell begins to increase with water but the


cell membrane can not release the solution and thus the water potential


within the cell increases. This causes the water to no longer enter the


cell. c) Hypotonic is less solute to a certain amount of water. Hypertonic


is more solute to a certain amount of water. Isotonic is the equal amount


of solutes in two different solutions. d) Endocytosis is the inward bulge


causes by incoming molecules. Exocytosis is the expelling of a material


outside a cell. e) Phagocytosis is the process where the cell obtains


solid matter. This is different from the pinocytosis where the cell


obtains liquid matter. These both are endocy

tic processes.


Receptor-mediated endocytosis is the process where there are interactions


between a material and receptor sites on the cell. In this process the


cell accepts the material if it matches with the receptor sites. f) Coated


pits are areas which peripheral proteins indent the membrane. This is


where the vesicles for certain materials are formed. The vesicle which is


formed is called the coated vesicle. g) Plasmodesmata are the links


which hold two adjacent cells together. Gap junctions are the channels


which allow materials to flow between cells.


2. The concentration gradient is the difference in the density of a


material from one region to another region. The concentration gradient


affects diffusion by allowing the substance to flow from high concentration


to low concentration. The concentration gradient affects osmosis by the


same manner it does in diffusion. The cell does not allow the solution to


exit the cell when water is entering. This keeps the solution in the cell


making the concentration high and thus no further penetration of water.


4. Diffusion is more rapid in gases because they are less dense than


liquids. They repel each other more resulting in faster diffusion.


Diffusion is greater at higher temperatures because of the greater kinetic


energy among the molecules. They push each other more making them less


dense.


5. The concentration of the solute is 1%. This happens because a 1% sugar


solution is isotonic with that of the 1% sugar solution in the tubes. The


2% sugar solution was increased because the substance was hypertonic. The


membrane did not allow the hypertonic solution to exit because the pressure


from the hypotonic solution was forcing water in. This later reached an


equilibrium when the hypertonic solution was gaining water potential and


the water stopped rising. The vice versa happened in the distilled water


solution.

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