Class 11 Biology NCERT Solutions For Chapter 13 – Photosynthesis In Higher Plants

NCERT Solutions for Class 11 Biology Chapter 13: What comes to your mind when you think about the different ways to score good marks in the CBSE Class XI Biology paper? A lot of things, right? Do you know about the most effective way to secure a good position in the Annual Exam? You don’t need to worry because in this blog we will be concentrating on an effective way to score good marks in the Bio paper.

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Here you will find the complete guide on CBSE 11th Biology Chapter 13 Solutions. You will find all the answers to the questions which are based on different sub-topics related to Photosynthesis.

NCERT Solutions For Class 11 Biology Chapter 13 – Photosynthesis In Higher Plants PDF

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Download NCERT Class 11 Biology Chapter 13 Solutions

The experts have done a lot of research before structuring the Chapter 13 Solutions Bio and they have tried to fulfill all the basic requirements of the students in the form of examples, diagrammatic representations along with solved answers.

What will you learn in NCERT Solutions For Class 11 Biology Chapter 13 Photosynthesis In Higher Plants?

Chapter 13 NCERT Bio Solutions for Class 11 falls under Unit 4, Plant Physiology, and this part centers around the basic processes that take place at the time of photosynthesis. The explanations that the experts have provided here are associated with the structure of the photosynthetic machinery and the various reactions that convert light energy into chemical energy. 

The other parts that have been dealt with care are the Splitting of Water, Cyclic and Noncyclic Photophosphorylation, Chemiosmotic Hypothesis, and Primary Acceptor of COz The Calvin Cycle Light Carbon dioxide Concentration Temperature and Water relation to Photosynthesis in Higher Plants in detail. The solutions have been shaped by following the latest CBSE pattern and it has been written in a language that will be easier to digest. 

We will now present you the topics/subtopics that fall under the 13^th chapter of NCERT solutions.

CBSE Class 11 Biology Chapter 13 NCERT Solutions Topic-Wise Listing

You will come across the solutions from the following topics/sub-topics in the NCERT solutions-

Here are the topics/ subtopics of the chapter:

13.1	What do we Know?
13.2	Early Experiments
13.3	Where does Photosynthesis take place?
13.4	How many Pigments are involved in Photosynthesis?
13.5	What is Light Reaction?
13.6	The Electron Transport
13.7	Where are the ATP and NADPH Used?
13.8	The C4 Pathway
13.9	Photorespiration
13.10	Factors affecting Photosynthesis

Advantages of following NCERT Solutions For Class 11 Biology Chapter 13 Photosynthesis In Higher Plants

There are different kinds of benefits for referring to the Class 11 Biology Chapter 13 Solutions and now we will talk about those solutions. You must collect it after you finish your syllabus.

• The students will be able to prepare themselves in a better way when they go through the contents of the Solutions For Class 11 Science Biology Chapter 13.
• The students will be able to cross all the hurdles in relation to the processes that take place in plants without any kind of fear.
• All the topics in connection with the basics of Photosynthesis In Higher Plants have been explained with proper illustrations and if you examine the contents carefully you will be left with zero queries.
• You will get new ideas to improve your methods of preparation and that is the beauty of following Solutions For Class 11 Biology Chapter 13 Photosynthesis In Higher Plants.
• Shaping study materials becomes easier for you when you are ready with solutions.

Access NCERT Solutions For Class 11 Biology Chapter 13

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

Though plants that are adapted to dry tropical climates have the C₄ pathway, they do not show any external morphologic characteristics. Hence it is not possible to say whether the plant is C₃ and C₄ by looking at its external appearance.

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

Leaves of C₄ plants have Krantz anatomy which makes them different than C₃ plants. C₄ plants also have specialized cells called bundle sheath cells which surround the vascular bundles. Every cell of the bundle sheath has chloroplasts. The mesophyll cells of leaves do not differentiate into the spongy and palisade parenchyma possessing fewer intercellular spaces while there is a normal occurrence of chloroplasts in the mesophyll cells. But in C₃ plants, the bundle sheath does not exhibit chloroplast, and the mesophyll cells of the leaves are differentiated into the spongy and palisade parenchyma. Hence by examining the internal structure, we can tell whether the plant is C₃ or C₄.

3. Even though very few cells in a C₄ plant carry out the biosynthetic–Calvin pathway, they are highly productive. Can you discuss why?

Plant productivity can be estimated by the rate at which photosynthesis takes place. The amount of carbon dioxide in a plant is directly proportional to the rate of photosynthesis. In C₄ plants, very few of the cells carry out the biosynthetic pathway yet they are highly productive for the following reasons.

• They have a mechanism that increases the CO₂ concentration at the site of the enzyme.
• Mesophyll cells are broken down in the bundle sheath cells resulting in CO₂ release which in turn increases the intracellular CO₂ concentration.
• Rubisco functions as a carboxylase minimizing the oxygenase activity.
• An increase in photosynthesis makes C₄ plants more productive.

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

The affinity of RUBISCO is much higher than its affinity for Oxygen. It is the concentration of Oxygen and CO₂

that determines the binding of the enzyme. Mesophyll cells of C₄ plants lack this enzyme but are found in the bundle sheath cells that girdle the vascular bundles where the Calvin cycle occurs.

Rubisco functions as oxygenase when the concentration of Oxygen is higher and it acts as carboxylase when the concentration of CO₂ is high. In the mesophyll cells, the primary carbon dioxide acceptor is a three-carbon compound – phosphonyl pyruvate which is converted into a four-carbon compound, oxaloacetic acid or OAA. This is converted further into malic acid which is transported to the bundle-sheath cells where it undergoes decarboxylation and carbon fixation takes place through the Calvin cycle which prevents Rubisco from serving as an oxygenase.

5. 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 pigment?

In the absence of chlorophyll-a photosynthesis will not take place because chlorophyll-a is a reaction center responsible for the conversion of solar energy into chemical energy. Although chlorophyll is the primary pigment that traps sunlight accessory pigments like chlorophyll-b, xanthophyll’s, and carotenoids also absorb sunlight and transfer energy to chlorophyll-a.

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

Chlorophyll fails to absorb the energy in the absence of light; hence it loses stability to give the leaf yellow coloration. This proves that carotenoids which impart yellow color are more stable.

7. Look at the 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 in the shade get less sunlight to carry out photosynthesis than the plants kept in sunlight. In leaves that get less sunlight, more chlorophyll is present to carry out photosynthesis efficiently. In the presence of strong light, the orientation of the chloroplasts in the mesophyll cells is irregular and in vertical files along the walls. Also, in bright light, photooxidation of chloroplasts takes place while non-oxidation takes place in shaded regions. Hence the plants kept in the shade have dark green leaves due to the high concentration of chlorophyll.

8. Figure 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?

a) Light is a limiting factor at A and 50% of B which is due to the increase in the photosynthetic rate with an increase in the intensity of light

b) Light, CO₂ and H₂O could be the limiting factor/s in region A.

c) C indicates a stage beyond which light is not a limiting factor and D is the line beyond which the intensity of light does not affect the photosynthetic rate.

9. Give a comparison between the following:

(a) C₃ and C₄ pathways

(b) Cyclic and non-cyclic photophosphorylation

(c) Anatomy of leaf in C₃ and C₄ plants

a) C₃ and C₄ pathways

b) Cyclic and non-cyclic photophosphorylation

c) Anatomy of leaf in C₃ and C₄ plants

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