NEETClass 11thClass 12thClass 12th PlusJEEClass 11thClass 12thClass 12th PlusClass 6-10Class 6thClass 7thClass 8thClass 9thClass 10thOnline CoursesDistance LearningInternational OlympiadNEETClass 11thClass 12thClass 12th PlusJEE (Main+Advanced)Class 11thClass 12thClass 12th PlusJEE MainClass 11thClass 12thClass 12th PlusClass 6-10Class 6thClass 7thClass 8thClass 9thClass 10thKCET/MHT-CETKCETMHT-CETNEET20262025202420232022JEE20262025202420232022Class 6-1020262025JEE MainPrevious Year PapersSample PapersMock TestResultAnalysisSyllabusExam DatePercentile PredictorAnswer KeyCounsellingEligibilityExam PatternJEE MathsJEE ChemistryJEE PhysicsJEE AdvancedPrevious Year PapersSample PapersMock TestResultAnalysisSyllabusExam DateAnswer KeyEligibilityExam PatternRank PredictorNEETPrevious Year PapersSample PapersMock TestResultAnalysisSyllabusExam DateCollege PredictorAnswer KeyRank PredictorCounsellingEligibilityExam PatternBiologyNCERT SolutionsClass 6Class 7Class 8Class 9Class 10Class 11Class 12TextbooksCBSEClass 12Class 11Class 10Class 9Class 8Class 7Class 6SubjectsSyllabusNotesSample PapersQuestion PapersICSEClass 10Class 9Class 8Class 7Class 6State BoardBiharKarnatakaMadhya PradeshMaharashtraTamilnaduWest BengalUttar PradeshOlympiadMathsScienceEnglishSocial ScienceNSOIMONMTCTALLENTEXASATInstant Online ScholarshipAIOT(NEET)ALLEN for SchoolsAbout ALLENBlogsNewsCareersRequest a call backBook a demo
NCERT Solutions Class 11 Biology Chapter 11 - Photosynthesis in Higher Plants
NCERT Solutions for Class 11 Biology Chapter 11 (Photosynthesis in Higher Plants) explain how green plants use light energy to prepare food from carbon dioxide and water. The chapter covers important topics such as photosynthetic pigments, light reactions, electron transport, photophosphorylation, the Calvin cycle, C3 and C4 pathways, photorespiration, and factors affecting photosynthesis. Students can understand how light energy is converted into chemical energy and how photosynthesis supports life by producing food and releasing oxygen.
NCERT Solutions for Class 11 Biology Chapter 11 by ALLEN explain the different stages of photosynthesis, including the light reaction and the biosynthetic phase. Students can learn about Photosystem I and Photosystem II, the Z-scheme, chemiosmosis, RuBisCO, the Calvin cycle, and the differences between C3 and C4 plants. These solutions follow the topics covered in NCERT Class 11 Biology Chapter 11 and help students prepare for questions on photosynthesis in NEET and other exams.
1.0NCERT Solutions for Class 11 Biology Chapter 11 Photosynthesis in Higher Plants: Key Concepts
Class 11 Biology Chapter 11, Photosynthesis in Higher Plants, explains how green plants use light energy to prepare organic food from carbon dioxide and water. The key concepts covered in this chapter include:
- Photosynthetic Pigments: Study the roles of chlorophyll a, chlorophyll b, xanthophylls, and carotenoids, along with their absorption and action spectra.
- Light Reaction: Understand how light energy is absorbed and used for water splitting, oxygen release, ATP formation, and NADPH formation.
- Photosystems and Electron Transport: Learn about Photosystem I (PS I), Photosystem II (PS II), electron transport, and the Z-scheme, along with cyclic and non-cyclic photophosphorylation.
- Chemiosmotic Hypothesis: Understand how the movement of protons across the thylakoid membrane creates a proton gradient that helps in ATP synthesis.
- Dark Reaction: Learn how ATP and NADPH produced during the light reaction are used in the fixation of carbon dioxide.
- C₃ Pathway: Study the Calvin cycle and its three main stages: carboxylation, reduction, and regeneration.
- C₄ Pathway: Understand the Hatch-Slack pathway, the role of Kranz anatomy, and how C₄ plants reduce photorespiration.
- Photorespiration: Learn about the C₂ cycle, its occurrence in C₃ plants, and its effect on photosynthetic efficiency.
- Factors Affecting Photosynthesis: Understand the effect of light, carbon dioxide concentration, temperature, and water on photosynthesis and study Blackman's Law of Limiting Factors.
2.0NCERT Solutions Class 11 Biology Chapter 11 - Photosynthesis in Higher Plants: Detailed Solutions
- By looking at a plant externally, can you tell whether a plant is or ? Why and how? Ans. It is not possible to distinguish externally between a and plant, but generally tropical plants are adapted for cycle.
- By looking at which internal structure of a plant you can tell whether a plant is or ? Explain. Ans. plants live in hot moist or arid and nonsaline or saline habitats. Internally the leaves show kranz anatomy. In kranz anatomy, the mesophyll is undifferentiated and its cells occur in concentric layers around vascular bundles. Vascular bundles are surrounded by large sized bundle sheath cells which are arranged in a wreath-like manner (kranz - wreath). The mesophyll and bundle sheath cells are connected by plasmodesmata or cytoplasmic bridges. The chloroplasts of the mesophyll cells are smaller. They have well developed grana and a peripheral reticulum but no starch. Mesophyll cells are specialised to perform light reaction, evolve and produce assimilatory power (ATP and NADPH). They also possess enzyme PEPcase for initial fixation of The chloroplasts of the bundle sheath cells are agranal.
- Even though a very few cells in a plant carry out the biosynthetic - Calvin pathway, yet they are highly productive. Can you discuss why? Ans. Since,through cycle, a plant can photosynthesise even in presence of very low concentration of (upto 10 parts per million), the partial closure of stomata due to xeric conditions would not bring much effect. Therefore, the plants can adapt to grow at low water content, high temperature and bright light intensities. This cycle is specially suited to such plants which grow in dry climates of tropics and subtropics. Besides, the photosynthetic rate remains higher due to absence of photorespiration in these plants. It can be visualised that both cycle and photorespiration are the result of evolution or might have been oneof the reasons of evolution for the adaptation of plants to different environments. plants are about twice to efficient as plants in converting solar energy into production of dry matter.
- RuBisCO is an enzyme that acts both as a carboxylase and oxygenase. Why do you think RuBisCO carries out more carboxylation in plants? Ans. RuBisCO is an enzyme which acts both as carboxylase (carboxylation during photosynthesis) and oxygenase (during photorespiration). But RuBisCO carries out more carboxylation in plants. In plants, initial fixation of carbon dioxide occurs in mesophyll cells. The primary acceptor of is phosphoenol pyruvate or PEP. It combines with carbon dioxide in the presence of PEP carboxylase or PEPcase to form oxaloacetic acid or oxaloacetate. Malic acid or aspartic acid is translocated to bundle sheath cells through plasmodesmata. Inside the bundle sheath cells they are decarboxylated (and deaminated in case of aspartic acid) to form pyruvate and is again fixed inside the bundle sheath Cells through Calvin cycle. RuBP of Calvin cycle is called secondary or final acceptor of in plants. Pyruvate is sent back to mesophyll cells.
- Suppose there were plants that had a high concentration of chlorophyll , but lacked chlorophyll , would it carry out photosynthesis ? Then why do plants have chlorophyll and other accessory pigments ? Ans. Plants that do not possess chlorophyll will not carry out photosynthesis because it is the primary pigment and act as the reaction centre. It performs the primary reactions of photosynthesis or conversion of light into chemical or electrical energy. Other photosynthetic pigments are called accessory pigments. They absorb light energy of different wavelengths and hence broaden the spectrum of light absorbed by photosynthetic pigments. These pigments hand over the absorbed energy to chlorophyll .
- 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? Ans. Carotenoid pigments are found in all photosynthetic cells. They are accessory pigments also found in roots, petals etc. These pigments do not breakdown easily thus temporarily reveal their colour due to unmasking, following breakdown of chlorophylls. Thus the colour of leaf kept in dark is yellow or pale green.
- 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? Ans. The leaves of the shaded side are darker green than those kept in sunlight due to two reasons: (i) The chloroplasts occur mostly in the mesophyll cells along their walls for receiving optimum quantity of incident light. (ii) The chloroplasts align themselves in vertical position along the lateral walls of high light intensity and along tangential wails in moderate light.
- The given 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 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?
Ans.
(a) At regions A and B light is the limiting factor. (b) In region A, light is the limiting factor. (c) C is the region where the rate of photosynthesis is not increased when light intensity is increased. D is the point where some other factors become limiting.
- Give comparison between the following: (a) and pathways (b) Cyclic and non-cyclic photophosphorylation (c) Anatomy of leaf in and plants.
Ans.
(a)The differences between and
(b) The differences between cyclic and non- cyclic photophosphorylation are as follows :
(c) Differences between the leaf anatomy of and plants are as follows :
3.0NCERT Class 11 Biology – Chapter-Wise Solutions & Explanations
Get NCERT Solutions for Class 11 Biology for All Chapters with explicit solutions to the problems asked in the textbook. Learn important concepts, revise key topics, and build a strong foundation in Biology for your exams.
4.0Key Features of NCERT Solutions for Class 11 Biology Chapter 11
- Z-Scheme and Electron Transport: Clear explanation of how electrons move from water to NADP⁺ through Photosystem II and Photosystem I during the light reaction.
- C3 and C4 Comparison: Easy comparison of C3 and C4 plants based on Kranz anatomy, the first stable product, and their photosynthetic pathways.
- RuBisCO and Photorespiration: Simple explanation of how RuBisCO works as a carboxylase or oxygenase depending on the concentration of CO₂ and O₂.
- Chemiosmosis: Step-by-step explanation of how the proton gradient develops across the thylakoid membrane and helps in ATP formation through ATP synthase.
- Prepared by Expert Faculty: Prepared by ALLEN subject experts with explanations based on the concepts and pathways covered in NCERT Class 11 Biology Chapter 11.
- Limiting Factors: Clear explanation of Blackman’s Law of Limiting Factors and how light, carbon dioxide, temperature, and water affect the rate of photosynthesis.
- Complete NCERT Exercise Coverage: Solutions to all NCERT exercise questions with clear explanations to help students understand photosynthesis and related processes.