# Finding the isotonic point for potato tissue

by nonop (student)

Noémie Pauwels

BIOLOGY COURSE WORK

Finding the isotonic point for potato tissue

• Raw results table

• Processed results table

• Example calculations

For 0.0 M :

1. Difference in mass

First trial :         Starting mass = 2.90g

Final mass = 3.05g

Difference in mass =  final mass – starting mass

= 3.05-2.90

= 0.15g

1. Percentage change in mass

First trial :   Percentage change =

=

= 5.17%

1. Mean percentage change in mass

Mean =

=

= 5.41%

1. Standard deviation of percentage change in mass

S.D. = √

= √

= 0.82%

• Discussion :

Description :

• The isotonic point of the potato stick is 0.31 M.
• Between 0.3 M and 0.0 M, the mass of the potato stick increases as the concentration of sucrose solution decreases.
• Between 0.32 M and 1.0 M, the mass of the potato stick decreases as the concentration of sucrose solution increases.

Explanation :

A : At 0.31 M, the potato sticks do not change

in mass. This is because the concentration of

the sucrose solution and the concentration of

the solute in the cell cytoplasm is the same,

they are isotonic.  There is no net movement

of water particles into/ out of the cells by osmosis.

B : Between 0.3 M and  0.0 M the potato sticks

gain mass as the sucrose solution became more

dilute. The water particles entered the cells by

osmosis from the more dilute ...