hello homosapiens.
here are some must know facts:

Photosynthesis

1. If photosynthesis has taken place, then glucose must first be formed from carbon dioxide.


2. When glucose is formed more quickly than it is used up, the excess glucose is change to sucrose before converting into starch before being transferred to stem,root,flower and etc for storage.


3. Starch formation is not photosynthesis but it is the work of subcellular compartmentation.
4. http://jxb.oxfordjournals.org/content/vol54/issue382/images/large/erg074f1.jpeg for more info
   

Okay. so here's a few question we asked ourselves during the practical last Friday .

Practical on Friday

1. Why did the leaf keep floating ?!
   
2. What is the purpose of boiling the leaf why not just burn it or something ?


3. Why alcohol not other liquid substances?

Our views:

1. The leaf kept floating as some plants open their stomata at high temperatures. When the leaf was boiled the in water, it stomata opened and the gases in it was released out. That was why a lot of small bubbles was formed on the underside of the leaves. Another reason would simply be that the leaf was less dense compared to the water due to the amount of air inside the leaf,air is less dense then water.
2. It was to denature the enzymes present in the leaves so the stored starch will not be broken down. If the starch is broken down into glucose, the glucose is to minuscule in size for the iodine solution to 'detect' since it only checks for presence of starch molecule.
3. Solutions like methanol(wood alcohol),Ethanol(denatured alcohol),Propanol and Butanol(both are fuel like alcohol) but mostly widely used alcohol are methanol and ethanol are used to break cell membranes,allowing chlorophyll to be released into the water. Chlorophyll dissolves easily in ethanol/methanol. After the decolourization,checking for starch presence is easy. This is also why the water in the test tube turns green.
4. 

   warning: this might make your head go > boom. so take your time to digest.
   

and lastly, remember to attempt the questions for the experiment we did. see you guys tomorrow. glenn and edited by wilber