PHOTOSYNTHESIS(6):TESTING FOR STARCH IN A LEAF

Question 1

During photosynthesis how is light energy absorbed?

Answer 1

By a green pigment called chlorophyll

Question 2

What does the absorption of light energy allow?

Answer 2

(Photosynthesis), allows it to CONVERT 6CO2(Carbon dioxide) and 6H20(water) into C6H1206(glucose)

Question 3

What are the different uses of the main product of photosynthesis?(glucose)

Answer 3

Can be transported to the growing parts of the plant(for use in respiration)

Transformed into cellulose, protein, lipids

TURNED INTO STARCH FOR STORAGE

Question 4

How do you see if a plant has been photosynthesising?

Answer 4

test the leaf to see if starch is present

Question 5

What chemical is used to test the presence of starch?

Answer 5

Iodine solution

Question 6

What is the first step in the experiment of testing the presence of starch in a leaf?

Answer 6

Heat the leaf in boiling water for 30 secs

Which kills the leaf, stopping any chemical reactions

Question 7

What is the second step in the experiment of testing the presence of starch in a leaf?

Answer 7

Add the leaf to a test tube of ethanol in a boiling water bath for a few minutes

The boiling ethanol dissolves the chlorophyll and removes the green colour from the leaf

Question 8

What is the fourth step in the experiment of testing the presence of starch in a leaf?

Answer 8

Add Iodine solution from a dropping pipette

After a few minutes, parts the leaf that contain starch will blue/black

Question 9

Is ethanol a risk hazard?why?

Answer 9

it is highly flammable

Question 10

What can you do as a control measure to ensure safety in the experiment?

Answer 10

Do not boil the ethanol with a Bunsen burner, it may ignite, instead use a boiling water bath