Science, asked by sktomardelhi, 1 year ago

Rohit places a potted plants in a room in complete darkness after 3 days he takes out the plant and test the leaf for the presence of starch will be get positive starch test?

Answers

Answered by DSamrat
27
Hey.

As Rohit has placed the potted plant in a complete dark room for 3 days, the leaf will lack starch .

The process of strach formation or photosynthesis requires sunlight.

Photosynthesis (Greek word photos: light; synthesis-, putting together) is the process by which the green plants synthesise their own food (glucose) using carbon dioxide and water as raw materials in presence of sunlight and chlorophyll. During this process oxygen is released as a by-product. The overall process of photosynthesis can be represented by the following equation:

6CO2 + 12H20 --> C6H12O6 + 6H2O + 6O2
in the presence of sunlight and chlorophyll .

It is a process used by plants to convert light energy (sunlight ) into chemical energy (starch)
in the presence of chlorophyll , CO2 and sunlight .

But as the plant was placed in the dark , it was unable to form any starch and it must have also consumed the starch it has earlier formed because for 3 days it was under darkness.

When we will put leaf kept in darkness in iodine solutions it will remain yellow that shows the absence of starch. If the leaf will contain starch it will turn blue-black showing that it has performed photosynthesis.
But in our case it will remain yellow.

Hence, the test for the presence of starch in the leaf will not give a positive result for sure because light is the basic requirement of starch formation .

Thanks.
Answered by Anonymous
11

\textbf{Answer :}



\textbf{Photosynthesis :}



It is a process by which green plants make their food.

Equation :-

6CO2 + 6H2O -----> C6H12O6 + 6O2


\textbf{How to check the presence of starch in leaves ?}


Take a potted plant and put in a dark room.

After sometime pluck a leave from the plant.

Then boil it in water for 5 min to soft it and after doing that place the leave in a test tube containing alcohol.

Place the test tube in a beaker containg water.

Then, genlty heat the beaker till the alcohol dissolves in the chrolophyll and the leaves loses its green colour.

Wash the leaf and Water.

After doing that place the leaf on a plate and add a few drops of iodine solution.

The parts that turn blue black show the presence of starch in a leaf.

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