Activity: Take a healthy potted plant wi...

Activity: Take a healthy potted plant with elongated leaves. Select a leaf and insert about one half of this leaf in a test tube containing KOH and make it air tight. Place the set -up in sun for two hours. Take out the leaf from the test tube and dip it in boiling water for a few minutes. Put this leaf in a beaker with alcohol and boil it in a water bath. Wash the leaf with water and then dip the leaf in iodine solution for a few minutes. The portion of the leaf dipped in KOH solution will not show any change when dipped in iodine solution.

The function of KOH taken in the test tube is to absorb-

Released water vapours

Released `CO_(2)`

Released `O_(2)`

Chlorophyll

Verified by Experts

In an experiment to test the presence of starch in a leaf, the plucked leaf is first boiled in water for a few minutes. This is an important step in the experiment because it:

converts glucose made in the leaf into starch

dissolves chlorophyll present in the green leaf

extracts starch to destarch the leaf

makes the leaf more permeable to iodine solution

Exposed part of leaf tested positive

Portion that was in the tube, tested positive

Entire leaf tested negative

Entire leaf tested positive

to dissolve the waxy cyticle

to make the cells more permeable to iodine solution

to remove the chlorophyll

to stop chemical reactions in the cells