NCERT Solutions for Class 11 Biology Chapter 11 Photosynthesis in Higher Plants
The NCERT Solutions for Class 11 Biology Chapter 11 Photosynthesis in Higher Plants explains how photosynthesis occurs, which supports life on Earth. Difficult topics like light reactions, the Calvin cycle, and photorespiration are explained clearly, along with the role of pigments that capture light energy. Flowcharts and diagrams are added so that students can easily learn the sequence. Through NCERT Solutions, students can improve their understanding and strengthen their weak areas.
This Story also Contains
- Download Photosynthesis in Higher Plants NCERT Solutions PDF
- Access Class 11 Biology Chapter 11 Photosynthesis in Higher Plants Solutions
- Approach to Solve Photosynthesis in Higher Plants Class 11 Question Answer
- Important Question of NCERT Class 11 Biology Chapter 11
- What Students Learn from Photosynthesis in Higher Plants NCERT Solutions
- What Extra Should Students Study Beyond the NCERT for NEET?
- Chapter Wise NCERT Solutions for Class 11 Biology
The Photosynthesis in Higher Plants class 11 question answer tells us about how food is prepared. Plants use sunlight, water, and carbon dioxide to prepare food. If students are facing difficulty in learning the concepts, they are at the right place. These solutions also highlight the differences between C3 and C4 pathways, making it easier to compare how plants adapt to different conditions. The NCERT Solutions for Class 11 Biology are a valuable resource for performing well in school exams as well as in competitive exams like NEET.
Download Photosynthesis in Higher Plants NCERT Solutions PDF
Photosynthesis is how plants make food using sunlight. Some topics can be confusing, but with easy solutions, students can understand step by step. Students can download a PDF of Class 11 Biology Chapter 11 Photosynthesis in Higher Plants question answer, which follows the latest NCERT guidelines closely.
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Access Class 11 Biology Chapter 11 Photosynthesis in Higher Plants Solutions
All the questions given in the textbook are explained in simple and clear language. Practising the Class 11 Biology Chapter 11 Photosynthesis in Higher Plants question answers helps students to improve their basic knowledge.
Q1. By looking at a plant externally, can you tell whether a plant is C3 or C4? Why and how?
Answer:
No, you can't determine whether a plant is C3 or C4 by simply observing it from the outside. Both plants can have the same leaf size and shape. For instance, wheat (a C3 plant) and maize (a C4 plant) can appear the same, but they employ different mechanisms for photosynthesis. To properly identify them, you must observe their internal structures.
- External appearance cannot be trusted: Leaf size and shape may be the same in both forms.
- Internal structure is the key: You must examine the anatomy of the leaf to identify the type.
Q2. By looking at the internal structure of a plant, can you tell whether a plant is C3 or C4? Explain.
Answer:
The main internal feature that helps differentiate C3 and C4 plants is known as Kranz anatomy.
- C4 plants possess a distinct cell arrangement to effectively capture carbon dioxide.
- C4 plants alone possess Kranz anatomy: Efficient fixation of carbon is permitted.
- Different structures of the cells: The Chloroplast arrangement between the two groups is quite different.
This can be observed under a microscope. Here’s how they differ:
| Feature | C3 Plants | C4 Plants |
|---|---|---|
| Bundle Sheath Cells | Small with fewer chloroplasts | Larger with chloroplasts that lack grana |
| Mesophyll Cells | Organised into palisade and spongy layers | Arranged in concentric circles around vascular bundles |
| Chloroplasts | Contain grana | Do not contain grana in bundle sheath cells |
Answer:
C4 plants are very productive due to their special mechanism of concentrating carbon dioxide, which increases the efficiency of photosynthesis.
Concentration of CO2: In mesophyll cells, CO2 is fixed into a 4-carbon compound, which is transported to bundle sheath cells and released CO2 there, ensuring a constant supply.
Lower photorespiration: With high CO2 levels and low O2 in bundle sheath cells (due to reduced PSII activity), RuBisCO acts mainly as a carboxylase, preventing energy loss.
Thus, even though only bundle sheath cells perform the Calvin cycle, the CO2 concentrating mechanism makes C4 plants more efficient and productive than C3 plants.
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:
RuBisCO can bind to both CO2 and O2. In C4 plants, conditions inside bundle sheath cells favour carboxylation:
High CO2 concentration: CO2 is delivered from mesophyll cells and released near RuBisCO in bundle sheath cells.
Low O2 levels: Bundle sheath cells have little PSII activity, so oxygen evolution is minimal.
This special environment ensures RuBisCO works mainly as a carboxylase, thereby increasing photosynthetic efficiency in C4 plants.
Answer:
Plants with chlorophyll b alone cannot perform photosynthesis effectively because chlorophyll a plays a vital role in the process:
- Role of chlorophyll a: It is the primary pigment for the absorption of light energy and starting the process of photosynthesis by donating electrons to be utilised in energy formation.
- Process of accessory pigments and chlorophyll b: Chlorophyll b helps in the absorption of other wavelengths of light and transfers that energy to chlorophyll a, but is unable to carry out its vital function.
Thus, in the absence of chlorophyll a, there cannot be photosynthesis, even with the presence of chlorophyll b.
- Chlorophyll a is required for photosynthesis: No chlorophyll a = no photosynthesis.
- Chlorophyll b is helpful but can't replace chlorophyll a's role: It helps to trap light but doesn't initiate the process.
Answer:
When leaves are stored in the dark, they tend to become yellow or pale green for several reasons:
- Degradation of chlorophyll: Chlorophyll needs light to be produced; in the absence of light, it begins to break down. When chlorophyll degrades, the green colour disappears.
- Exposure of accessory pigments: When chlorophyll is reduced, other pigments such as carotenoids are exposed, which causes leaves to turn yellow.
- This process shows how important light is in keeping healthy green leaves.
- Chlorophyll breaks down in the dark, causing yellowing.
- Accessory pigments such as carotenoids become apparent, adding to the yellow colour.
Answer:
Shaded leaves are darker green than sun-exposed leaves for several reasons:
- Chloroplast orientation and packing: Chloroplasts in shaded places can be packed more densely or have a different orientation within mesophyll cells to capture more light.
- Reduced photo-oxidation in shade: In intense sunlight, some chlorophyll can be damaged or oxidised; however, shaded leaves have more intact chlorophyll since they receive milder light.
- Therefore, leaves that are shaded tend to be darker green because they have healthier chlorophyll.
- Increased chlorophyll in shaded leaves makes the colour darker.
- Lower damage from excessive sunlight preserves levels of chlorophyll.
(a) At which point/s (A, B, or C) in the curve is light a limiting factor?
Answer:
At A point, light is the limiting factor because the rate of photosynthesis is minimal here.
(b) What could be the limiting factor/s in region A?
Answer:
In region A, light is a limiting factor. The other limiting factors in this region can be temperature, CO2 and H2O.
(c) What do C and D represent on the curve?
Answer:
C represents 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 rate of photosynthesis.
Q9. Give a comparison between the following:
(a) C3 and C4 pathway
Answer:
C3 Pathway | C4 Pathway |
There are plants in which the first stable product after the carbon assimilation is a 3-carbon molecule, i.e., 3-phosphoglyceric acid. These plants are called C3 plants, while the pathway for carbon assimilation in them is called the C3 pathway. | In the plants found in the tropical area, the first stable product after carbon assimilation is a 4-carbon molecule or oxaloacetic acid, instead of a 3-carbon compound. These plants are called C4 plants, and the pathway of carbon fixation is called the C4 pathway. |
The cells involved are mesophyll cells. | The cells involved are mesophyll cells and bundle sheath cells |
Most common in plants worldwide. | It is seen in tropical plants. |
RuBisCO acts directly in mesophyll cells. | PEP carboxylase in mesophyll; RuBisCO in bundle sheath. |
Q9. Give a comparison between the following:
(b) Cyclic and non-cyclic photophosphorylation
Answer:
Cyclic photophosphorylation | Non-cyclic photophosphorylation |
Only photosystem I is involved in cyclic photophosphorylation | Both photosystems I and II are involved in non-cyclic photophosphorylation |
The active reaction centre is P700 | The active reaction centre is P680 |
Electron transportation occurs in a cyclic manner | Electron transport occurs in a non-cyclic manner |
Oxygen evolution does not occur | Oxygen is released as a by-product |
Only ATP is produced | Both ATP and NADPH are produced |
Q9. Give a comparison between the following:
(c) Anatomy of a leaf in a C3 and a C4 plant
Answer:
Anatomy of a leaf in C3 plants | Anatomy of a leaf in C4 plants |
Bundle sheath cells are absent. | Bundle sheath cells are present around the vascular bundles. |
RuBisCO is found in mesophyll cells. | RuBisCO is found in bundle sheath cells. |
Plants do not possess 'Kranz' anatomy of leaves. | Leaves show Kranz anatomy. |
Chloroplasts are of a single type only, | Chloroplasts are dimorphic. The chloroplasts of bundle sheath cells are larger and arranged centripetally. |
Mesophyll cells have intercellular spaces. | Mesophyll cells do not have intercellular spaces. |
Approach to Solve Photosynthesis in Higher Plants Class 11 Question Answer
The student should start by thoroughly understanding the concepts like light reactions, the Calvin cycle, and photorespiration.
Diagrams and flowcharts can be used to have a visual understanding of the topics. Processes such as the Z scheme and cyclic vs non-cyclic photophosphorylation should be studied.
Focus should be given to the role of pigments and the factors affecting photosynthesis. Factors are well explained in Class 11 Biology Chapter 11 Photosynthesis in Higher Plants question answer.
The NCERT Solutions for Class 11 are easy to understand and are presented in simple language. This encourages students to know the major concepts and perform well in exams.
- Practising the exemplar questions will also give an idea of the chapter. For better revision, students can refer to the Class 11 Biology Chapter 11 Photosynthesis in Higher Plants Solutions.
NCERT Solutions for Class 11: Subject-wise
Important Question of NCERT Class 11 Biology Chapter 11
Below is an important question from the chapter, along with the detailed solution. Referring to the NCERT Solutions for Class 11 Biology Chapter 11 Photosynthesis in Higher Plants helps students to know how to write answers in exams.
Q1. What is the correct sequence of the flow of electrons in the light reaction?
Answer:
In the light reaction, the proper order of electron flow is
PSII → Plastoquinone (PQ) → Cytochrome b6f → Plastocyanin (PC) → PSI → Ferredoxin → NADP⁺
Water photolysis: At photosystem II (P680), light energy excites electrons, and the lost electrons are replaced by those obtained from the splitting of water into H⁺, e⁻, and O2.
Electron transport: The electrons move through carriers (PQ, Cyt b6f, PC, PSI, and Fd), releasing energy for ATP formation.
NADPH formation: Finally, electrons reduce NADP⁺ to NADPH with the help of ferredoxin.
Check the NCERT Books and NCERT Syllabus here:
What Students Learn from Photosynthesis in Higher Plants NCERT Solutions
Living organisms depend on plants for food and oxygen. This chapter explains how plants trap light energy and convert it into chemical energy and prepare food.
Students learn about the light reaction process, including photophosphorylation and the role of pigments.
The Photosynthesis in Higher Plants class 11 question answer explains the Calvin cycle and how carbon dioxide is fixed.
Learners also understand factors affecting the rate of photosynthesis, such as light intensity, CO2 concentration, and temperature.
The Photosynthesis in Higher Plants NCERT Solutions describe the differences between the C3 and C4 pathways in plants.
Students explore the process of photorespiration and its significance in plant metabolism.
What Extra Should Students Study Beyond the NCERT for NEET?
Studying concepts beyond the NCERT will help in attaining conceptual clarity for the NEET exam. The NCERT Solutions for Class 11 Biology Chapter 11 Photosynthesis in Higher Plants help students to answer application-based questions. Some extra concepts that can be studied are:
Chapter Wise NCERT Solutions for Class 11 Biology
Below are the chapter-wise solutions:
Frequently Asked Questions (FAQs)
Q: How does the Calvin cycle work in plants?
A:
The Calvin cycle occurs in the chloroplast stroma. It makes use of light reaction ATP and NADPH to fix the carbon dioxide and form glucose.
Q: What is photosynthesis in higher plants?
A:
Higher plant photosynthesis is the process by which green plants utilize sunlight, carbon dioxide, and water to produce food. In this process, oxygen is also released as a waste product. This process is explained in detail in the NCERT Solutions for Class 11 Biology Chapter 11 Photosynthesis in Higher Plants.
Q: What are the two stages of photosynthesis?
A:
The two-stage of photosynthesis explained in the NCERT Solutions for Class 11 Biology Chapter 11 Photosynthesis in Higher Plants are:
- Light-dependent reactions (Light reactions) take place in the thylakoid membranes and yield ATP and NADPH.
- Light-independent reactions (Calvin cycle) happen in the stroma and incorporate ATP and NADPH in the production of glucose.
Q: What is the role of chlorophyll in photosynthesis?
A:
Chlorophyll is the pigment in plants which is green. It assists in trapping light energy, which helps in the production of food using water and carbon dioxide.
Q: What is the difference between cyclic and non-cyclic photophosphorylation?
A:
Only Photosystem I is involved in cyclic photophosphorylation, which makes ATP but neither NADPH nor oxygen.
Both Photosystems I and II are involved in non-cyclic photophosphorylation to produce ATP, NADPH, and oxygen.
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