A student was asked to put few raisins in water in a petri dish 'A' and few in a concentrated sugar solution in another petri dish 'B'. (a)what will be the change in raisins in petri dishes'A' and 'B'? (b)explain briefly the reason for above changes.
Answers
a)Changes in raisins in petri dishes A and B:
Petri dish A- in water.
The raisins will gain mass and will appear plumped up. The raisins have drawn in water and look bigger.
Petri dish B- concentrated sugar solution.
The raisins in this petri dish looked wrinkled and feel very soft. They appear smaller in size than the the raisins in the petri dish with water.
b) Reason for the changes:
The changes are due to the process of osmosis, which is movement of water molecules from a less concentrated solution to a more concentrated solution through a semi-permeable membrane.
Petri dish A:
Water is hypotonic to the cells of the raisins, hence the raisins draw in water and swell up.
Petri dish B:
The sugar solution is hypertonic to the cells hence the water is drawn out of the cells of the raisins therefore they wrinkle and get smaller.
Answer:
Raisin experiment
a)Changes in raisins in petri dishes A and B: Petri dish A- in water.The raisins will gain mass and will appear plumped up. The raisins have drawn in water and look bigger.Petri dish B- concentrated sugar solution. The raisins in this petri dish looked wrinkled and feel very soft. They appear smaller in size than the the raisins in the petri dish with water.
b) Reason for the changes:
The changes are due to the process of osmosis, which is movement of water molecules from a less concentrated solution to a more concentrated solution through a semi-permeable membrane. Petri dish A:
Water is hypotonic to the cells of the raisins, hence the raisins draw in water and swell up.
Petri dish B:
The sugar solution is hypertonic to the cells hence the water is drawn out of the cells of the raisins therefore they wrinkle and get smaller.