Coalition Chemistry 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 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 endocytic 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