CBSE Class 10 Science 2020 · Paper 31/5/2 · Question 28
Design an activity to show that chlorophyll is essential for photosynthesis.
Answer
A destarched variegated leaf kept in sunlight and tested with iodine turns blue-black only where it was green, so chlorophyll is essential.
Take a potted plant with variegated leaves; keep it in a dark room for three days to use up its starch, then in sunlight for about six hours. Pluck a leaf and trace its green areas on paper. Dip it in boiling water for a few minutes, then heat it in alcohol placed in a water bath until the alcohol boils (the chlorophyll dissolves). Dip it in dilute iodine solution for a few minutes and rinse it.
Observation: only the parts that were green turn blue-black.
Inference: starch, made by photosynthesis, forms only where chlorophyll is present, so chlorophyll is essential for photosynthesis.
🔒 Step-by-step solution
Sign up free to see every step of how it is worked out.
From the board paper
More questions from Life Processes
Class 10 Science — every question with an expert-verified, step-by-step solution.
- Q1 The kidneys in human beings are a part of the system for
- Q1 Why is diffusion insufficient to meet the oxygen requirements of…
- Q2 The xylem in plants are responsible for
- Q2 What criteria do we use to decide whether something is alive?
- Q3 The autotrophic mode of nutrition requires
- Q3 What are outside raw materials used for by an organism?
- Q4 The breakdown of pyruvate to give carbon dioxide, water and ener…
- Q4 What processes would you consider essential for maintaining life?
- Q5 How are fats digested in our bodies? Where does this process take…
- Q6 What is the role of saliva in the digestion of food?
- Q7 What are the necessary conditions for autotrophic nutrition and…
- Q8 What are the differences between aerobic and anaerobic respiration…
All 431 questions on Life Processes → Browse all Science chapters →