Last lab session continued

This experiment show how is the visking tubing partially permeable.

The first picture shows the results of the experiment. The test tube with the red precipitate is the test tube with glucose and Benedict solution was added to it, turning it red as glucose is a reducing sugar. The second test tube shows iodine being added to the test tube with the glucose solution to test it for starch. The last test tube shows that there is starch in the visking tubing as the iodine turned blue black.

The picture above shows the glucose solution with Benedict solution being heated up. It is being heated up to speed up the reaction.
The experiment is as follows.

1. Place a solution of starch and glucose in visking tube.
2. Place the visking tube in a beaker of water for sometime
3. Drop a few drops of Benedict solution into the beaker to show that glucose has move from the visking tube to the beaker.

From this experiment, I have learnt that the visking tube is partially permeable like the humans intestines. 

Last Lab Sesion

It was our last lab session for the term and we did 2 experiments, one of it was testing for starch on a leaf and the other was the use of visking tubing. 

 The pictures below shows the experiment of testing for starch on a leaf.
The picture on the top right shows the leaves in a hot water bath of ethanol.
At the top left the picture shows the leaf after being tested for starch with iodine. As shown, the green part of the leaf turns the iodine while the yellow part of the leaves make the iodine remains brownish- yellow.

The pictures above shows the ethanol after a leaf is being soaked in it. The ethanol turned green because of the chlorophyll in the leaf.
The steps for this experiment are as below:

1. Boil the leaf to break the structure of the leaf cells
2. Place the leaf in ethanol and place the ethanol in a hot water bath
3. Add a few drops of iodine on the leaf

From This experiment i learnt that for a leaf to photosynthsis it requires chlorophyll and chlorophyll can only be found in the area of the leaf.

The next post will show the other experiment about the visking tubing