Practical notes

  Dear students 

Here is the procedure for Physiology experiments

EX.NO.  1

DATE:

 

POTATO OSMOSCOPE

AIM:

To demonstrate endosmosis and exosmosis using potato tuber.

REQUISITES:

Potato tuber, coloured salt solution, water, petridishes, scalpel, knife and pins.

PROCEDURE:

The skin of the potato tuber was removed amd two identical cups were made. In the first cup coloured salt solution was taken and it was placed in petridish containing water. In the second cup, water was taken and placed in a petridish containing coloured salt solution. The initial level in both cups were marked with the help of pins.

OBSERVATION:

 

 

INFERENCE:

EX.NO.  2

DATE:

DETERMINATION OF OSMOTIC PRESSURE BY PLASMOLYSIS METHOD

AIM:

To determine the osmotic pressure of Rhoeo leaf cells by plasmolytic method.

REQUISITES:

Rheoe leaf, one molar sugar solution, measuring cylinder, beaker, petridishes, distilled water, microscope, brush, slide, coverslip,and blade.

PROCEDURE:

One molar sugar solution was prepared and it was diluted to various concentration such as 0.1M, 0.2M, 0.3M, 0.4M and 0.5M. the solution were taken in labeled petridishes. The petridishes were shaken gently to mix the solution in a proper way. The lower epidermal peeling of Rhoeo leaves were taken and cut into uniform bits. They were kept immersed in the sugar solution for 45 mins. After 45 mins the peeling were mounted on the glass slides with respective solution and were examined under microscope. About 12 cells were taken at random and the number of plasmolysed cells were counted for each molar concentration of sugar solution.

The results were tabulated and the percentage of plasmolysis was calculated using the formula,

Percentage of plasmolysis= Number of cells plasmolysed x 100

                                                                Total number of cells

CALCULATION:

Osmotic pressure of the cell is calculated using the formula,

Osmotic pressure = 22.4x M x (T+t)  atm

                                                          T

M = Molar concentration of isotonic solution

T = Absolute temperature (in kelvin)

T = Room temperature.

 

 

 

 

 

 

 

 

 

 

 

OBSERVATION:

Concentration of sugar solution	No. of cells counted	No. of cells plasmolysed	Percentage of plasmolysis
0.1M
0.2M
0.3M
0.4M
0.5M

The solution in which more or less 50%  cells were plasmolysed was considered as isotonic solution.

 

 

 

 

INFERENCE