Aim:The aim of this investigation is to explore osmosis in potato
cells and find approximately the concentration of sucrose within
potato cells by measuring the change in mass of potato chips when
immersed in different sucrose solutions for a set period of time
Introduction: Osmosis happens in the cells of all living things. It is
a simple process where water molecules diffuse from one cell to
another through the partially permeable cell membrane. (the membrane
has tiny holes in it that allow simple molecules, such as water, to
pass through) During the process of osmosis, water moves between
higher and lower concentrated solutions of either saline or a sugar
solution until water molecules are evenly distributed between the two
(or more) solutions (until they reach equilibrium), and in the case of
cells, when the cells are of equal dilution. This movement of water is
In the example below, there are two unbalanced solutions separated by
a partially permeable membrane. Solution A has a higher concentration
of sugar molecules than Solution B.
As the process of osmosis begins, the water molecules from solution B
begin to move into solution A, seen below.
After time, enough water molecules have moved to achieve equilibrium,
and the process stops.
In this case the molecules are not of equal number. This means that,
if solution B was a cell, then it would of lost molecules and become
shrivelled, or flaccid, and cell A would of gained molecules and
become swollen, or turgid. This side effect can lead to cells either
dying from the lack of water in them or swelling to the extent that
they burst. This is only the case in animal cells that have no cell
wall like plant cells. Plant cells undergo the same process, but do
not burst as their cell wall is strong enough to stop any major
changes in cell structure. Plants rely on the turgidity of their cells
in order to stay stiff. This is why under watered plants wilt.
Prediction: The aim of this investigation is to explore osmosis in
potato cells and find the concentration of sucrose within. The osmosis
will be taking place across the partially permeable membranes of the
potato cells. It can be predicted, from previous knowledge, that the
sucrose concentration in a healthy potato cell is approximately 10%.
Therefore, any concentration that is weaker will add water to the
cells, causing them to become turgid and increase in mass, and any
concentration that is stronger will remove water from the cells,
causing them to become flaccid, and decrease in mass. At a solution
strength of approximately 10%, it can be predicted that little osmosis
will occur due to the similarity of the solutions inside and outside
of the potato cells.
Independent:Sugar concentration of...