explain activity 6.1, 6.2 and 6.3

The first two activities are already well explained in the study material at the link

 http://cbse.meritnation.com/study-online/study-material/m5ZTMnrFY@1eAvg0ZB9Gvg!!/N0jv10nZPt0ark5icVuYgg!!#3668 

Refer to this link and get back to us for doubts.

In the third activity, I am just providing you the logical reasoning as the steps are already provided to you.

When we perform the iodine test for both the tubes, the test tube in which saliva is added, shows less colouration of starch (blue black colour) as compared to the second tube.

This is because saliva has digested some percentage of starch in the tube.

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 AIM

to show that chlorophyll is essential for photosynthesis

MATERIALS REQUIRED

potted plant

a sheet of paper

beaker  of water

burner

alcohol

petridish

iodine solution

PROCEDURE

take a plant with variegated leaves {partly green and partly non green}

eg: money plant

keep the plant in a dark place for 3 days so that starch gets used up

place it in sunlight for 6 hours

pluck a leaf and mark the green areas ; trace it on a paper

boil the leaf first in water and then in alcohol. this decolourizes the leaf

place this beaker in a large beaker contaning water

heat till the alcohol begins to boil

place the leaf in  a petridish and pour iodine solution on it

take the leaf and rinse off the iodine solution

observe the colour and compare it with the tracing

OBSERVATION

green part of leaf has turned into dark blue colour and non green into yellow - colour of iodine solution

INFERENCE

dark blue colour indicates presence of starch and yellow portion has no starch

only chlorophyll contaning cells synthesis starch

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AIM

to show that carbon dioxide is essential for photosynthesis

MATERIALS REQUIRED

 2 potted plant A nd B

glass plate

bell jars

vaseline

alcohol

petridish

iodine solution

PROCEDURE

take 2  plant  of same species and same size

place them on separate glass plates

place a watch glass or petri dish with KOH near  plant A

 

cover them using bell jars

 

make the set up air tight by applying vaseline to seal bottom of jars

 

keep the plant in sunlight for 3 days

after 3 hrs pluck a leaf  from each plant

boil the leaf first in water and then in alcohol. this decolourizes the leaf

 

place the leaves in separate  petridish and pour iodine solution on it

OBSERVATION

 

leaf of plant A turns slightly blue or remains yellowish indicating presence of little or no starch

leaf of plant B turns deep blue black indicating presence of enough starch

 

 

 

 

 

 

 

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