Coalition Chemistry
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 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 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
water
solution.