Page 100 - Biology - XII

Results
1. The green colour of the extract disappears and it reappears shortly after sometime. Then add 5 ml of
water and then little ether. Shake the test tube.
2. Two distinct layers are formed. Upper layer has yellow carotenoids and lower layer has saponifi ed
green pigments.

Observations
Separation of yellow and green pigments

S. No. Experiment Observation Inference

1. In a test tube, take 1 ml of chlorophyll Green colour disappears
extract + 0.5 ml 30% KOH + 1 ml methyl Later reappears
alcohol

2. Add 5 ml water + little ether. Shake the Two layers are formed. Carotenoids and
mixture chlorophyll are present.

Conclusion
Chlorophyll extract has carotenoids and chlorophyll.

Precautions
1. Prepare fresh (green) leaves extract.
2. Also dried leaves extract can be used for study.

VIVA VOCE

Q1. Which pigments (colour) did you study?
Ans. Green pigments and yellow pigments

Q2. What are plastidial pigments?
Ans. The pigments present in plastids are called plastidial pigments
Q3. Name the pigments that you have studied.
Ans. Chlorophyll (A and B), carotenoids, xanthophylls

Q4. Why did you choose this experiment for study?
Ans. This experiment gives good colour variations and provides scope to study extracts of leaves of
diff erent plants.
Q5. Which pigments does the chlorophyll extract have?
Ans. Chlorophyll extract has green and yellow pigments.

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