CBSE Class 10 Biology - Questions and Answers Related to Activity To Show Chlorophyll is Necessary For Photosynthesis
Chapter: Life Processes (NCERT Book Activity 6.1)
Activity Steps
Step 1: Take a potted plant with variegated leaves – for example, a money plant or croton.
Step 2: Keep the plant in a dark room for three days so that all the starch gets used up.
Step 3: Now keep the plant in sunlight for about six hours.
Step 4: Pluck a leaf from the plant. Mark the green areas in it and trace them on a sheet of paper.
Step 5: Dip the leaf in boiling water for a few minutes.
Step 6: After this, immerse it in a beaker containing alcohol.
Step 7: Carefully place the above beaker in a water bath and heat till the alcohol begins to boil.
What happens to the colour of the leaf? What is the colour of the solution?
Step 8: Now dip the leaf in a dilute solution of iodine for a few minutes.
Take out the leaf and rinse off the iodine solution.
Observe the colour of the leaf and compare this with the tracing of the leaf done in the beginning.
What can you conclude about the presence of starch in various areas of the leaf?
Q1: What is mean by variegated leaves?
Answer: Leaves of plants are partly green and partly white.
Q2: Give an example of a plant with variegated leaves.
Answer: Money plant or Croton
Q3: Why is the plant kept in dark for three days?
Answer: To destarch its leaves i.e. plant should consume all the starch (as food energy) it has.
Q4: Why is the plant kept in sunlight for six hours (Step 3)?
Answer: Leaves do photosynthesis to prepare glucose and stores it as starch.
Q5: Why is the leaf kept in boiling water for a few minutes? (Step 5)
Answer: Boiling will break the cell wall and cell membrane making it more permeable to iodine solution.
Q6: Why is leaf dipped in an alcohol solution and boiled in boiling water? (Step 6 and 7)
Answer: Before testing for starch, chlorophyll has to be removed from the leaf. The presence of chlorophyll interferes with the starch test. The boiling alcohol removes chlorophyll.
Q7: What happens to the colour of the leaf? What is the colour of the solution?
Answer: The leaf becomes colourless (because chlorophyll has been removed.). The alcohol solution turns green.
Q8: What does iodine solution do?
Answer: Iodine solution is used to detect the presence of starch. Starch gives a blue-black colour with iodine.
Q9: (Step 8) What is the colour of the leaf and compare this with the tracing of the leaf done in the beginning? What can you conclude about the presence of starch in various areas of the leaf?
Answer: The part of the leaf which was originally green (due to chlorophyll) turns blue-black showing starch is present in this part. The areas which remain colourless show that no starch formation took place. It indicates that chlorophyll is necessary for the photosynthesis process.
Q10(MCQ): Photosynthesis is a/an
(a) biochemical process.
(b) physical process.
Answer: (a) biochemical process.
Q11: Does intensity of light affect the rate of photosynthesis?
Answer: As we increase from low light intensity to higher light intensity, the rate of photosynthesis will increase because there is more light available to drive the reactions of photosynthesis.
ЁЯСЙSee Also:
Ch 6 - Life Processes (Q & A)
Ch 6 - Life Processes (Nutrition) - Q & A
Ch 6 - Life Processes - Photosynthesis (Q & A)
Ch6 - Life Processes (MCQs)
Ch6 - Life Processes (Gist on Excretory System)
Ch 6 - Digestive Organs & Functions
Ch 6 - Life Processes (Assignment Q & A-1)
Ch 6 -Life Processes: 51 Questions You must Revise
Ch6 - Life Processes - Breathing - Pathway To Air
Ch 6 - Life Processes- TRANSPORTATION & EXCRETION - Assignment Sheet
Ch 6 - Arteries vs Veins (Important Differences)
Ch 6 - Five Digestive Juices
Ch 6 - Human Nutrition (VSQA - Worksheet)
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Ch 6 - Life Processes (Worksheet)
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