Investigating the Osmotic Values of Chinese Radish and Potato Cores

Investigating the Osmotic Values of Chinese Radish and

Potato Cores

Osmosis is the movement of water from an area of high water potential

(Ψ) to an area of low water potential through a selectively permeable membrane. The diagrams above shows that only the water molecules can move quickly through the pores in the selectively permeable membrane. The sugar molecules (glucose arde too big to move through the gaps withease. Since there is a higher water potential on the left-hand side more water molecules will move from right to left, than from left to right.

If a plant cell is placed in pure water, water outside the cell will flow into the cell by osmosis as the interior of the cell has a lower water potential than the pure water. The reason why the interior has a lower water potential is because the cytoplasm has substance like glucose dissolved into it. As more and more water flows into the cell the cell becomes more and more rigid. Eventually the cell becomes turgid and this is when the cell will not accept anymore water as the water potential inside and outside now balanced.

If we replicated this with an animal cell it would burst as water would enter osmotically and then the cell would become rigid and there would be no support from a cell wall, and thus the cell will burst.

Shrinkage of Cytoplasm Membrane being pulled away from the cell wall

In the conditions of 1.0M Glucose solution the cell will tend to lose water as it has a higher water potential than the outside medium,

Water leaves the cell via osmosis and the cell become less rigid in other words flaccid. If the water loss continues the cytoplasm shrinks and the membrane gets pulled away from the cell wall, leaving the cell in a state of plasmolysis. If this happens the plant will wilt.

How to make 1.0M Glucose Solution:

To make 1 1.0M Glucose solution the molecular mass of glucose in grams is dissolved in 1dcm-3 of water. Below is the molecular mass of glucose. C 6 H 12 O 6

(6x12)+(1x12)+(6x16)

72+12+96=180g

From 1.0M Glucose solution it is possible to make any desired molarities lower than 1.0M by mixing with the correct ratio of water.

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Molority M cm3 of water cm3 of 1.0M Glucose

0.2 8 2