NCERT Solutions for Class 11 Biology Chapter 13

Photosynthesis in Higher Plants Class 11

Chapter 13 Photosynthesis in Higher Plants Exercise Solutions

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Exercise : Solutions of Questions on Page Number : 224

Q1 :  

By looking at a plant externally can you tell whether a plant is C3 or C4? Why and how?


Answer :

One cannot distinguish whether a plant is C3 or C4 by observing its leaves and other morphological features externally. Unlike C3 plants, the leaves of C4 plants have a special anatomy called Kranz anatomy and this difference can only be observed at the cellular level. For example, although wheat and maize are grasses, wheat is a C3 plant, while maize is a C4 plant.

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Q2 :  

By looking at which internal structure of a plant can you tell whether a plant is C3 or C4? Explain.


Answer :

The leaves of C4 plants have a special anatomy called Kranz anatomy. This makes them different from C3 plants. Special cells, known as bundle-sheath cells, surround the vascular bundles. These cells have a large number of chloroplasts. They are thick-walled and have no intercellular spaces. They are also impervious to gaseous exchange. All these anatomical features help prevent photorespiration in C4 plants, thereby increasing their ability to photosynthesise.

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Q3 :  

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?


Answer :

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Q4 :  

RuBisCo is an enzyme that acts both as a carboxylase and oxygenase. Why do you think RuBisCo carries out more carboxylation in C4 plants?


Answer :

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Q5 :  

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?


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Q6 :  

Why is the colour of a leaf kept in the dark frequently yellow, or pale green? Which pigment do you think is more stable?


Answer :

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Q7 :  

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?


Answer :

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Q8 :  

Figure 13.10 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 is light a limiting factor?

(b) What could be the limiting factor/s in region A?

(c) What do C and D represent on the curve?


Answer :

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Q9 :  

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


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<< Previous Chapter 12 : Mineral Nutrition Next Chapter 14 : Respiration in Plants >>

Biology : CBSE NCERT Exercise Solutions for Class 11th for Photosynthesis in Higher Plants will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.

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