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• Give comparison between the following: (a) C3 and C4 pathways (b) Cyclic and non-cyclic photophosphorylation (c) Anatomy of leaf in C3 and C4 plants
  C₃ and C₄ pathways C₃ plants fix CO₂ directly via...
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• Figure 11.10 shows the effect of light on the rate of photosynthesis. Based on the graph, answer the following questions: (a) At which point/s (A, B or C) in the curve light is a limiting factor? (b) What could be the limiting factor/s in region A? (c) What do C and D represent on the curve?
  Light is the limiting factor at points A and B...
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• Look at leaves of the same plant on the shady side and compare it with the leaves on the sunny side. Or, compare the potted plants kept in the sunlight with those in the shade. Which of them has leaves that are darker green ? Why?
  Leaves on the shady side or from shade-grown plants are...
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• Why is the colour of a leaf kept in the dark frequently becomes yellow , or pale green? Which pigment do you think is more stable?
  In darkness chlorophyll synthesis ceases while degradation continues, leading to...
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• Suppose there were plants that had a high concentration of Chlorophyll b, but lacked chlorophyll a, would it carry out photosynthesis? Then why do plants have chlorophyll b and other accessory pigments?
  A plant lacking chlorophyll a cannot carry out photosynthesis because...
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• RuBisCO is an enzyme that acts both as a carboxylase and oxygenase. Why do you think RuBisCO carries out more carboxylation in C4 plants?
  In C₄ plants, bundle sheath cells maintain very high CO₂...
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• Even though a very few cells in a C4 plant carry out the biosynthetic – Calvin pathway, yet they are highly productive. Can you discuss why?
  C₄ plants concentrate CO₂ in bundle sheath cells around Rubisco,...
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