NCERT Solutions for Class 11 Biology Chapter 13 – Photosynthesis in Higher Plants
If you are a Class 11 student looking for reliable and easy-to-understand NCERT Solutions for Biology Chapter 13 Photosynthesis in Higher Plants, you have landed at the right place. Myclass24 provides well-researched, step-by-step answers to all the questions in this chapter, whether it is about the light reactions, the Calvin cycle, or the differences between C3, C4, and CAM plants. Photosynthesis is one of the most fundamental biological processes on Earth, and understanding it thoroughly is not just important for your board exams but also for competitive entrance exams like NEET. Must check the CBSE resources and NCERT Solutions.
The solutions available on Myclass24 are written in simple language, aligned with the latest NCERT syllabus, and are designed to help students in India and abroad score maximum marks. Whether you are from Delhi, Mumbai, Bengaluru, or any other city preparing for your Class 11 final exams, these solutions will help you build a strong conceptual foundation in plant physiology.
NCERT Solutions for Class 11 Biology Chapter 13 PDF – Photosynthesis in Higher Plants
Download the free PDF of NCERT Solutions for Class 11 Biology Chapter 13 Photosynthesis in Higher Plants from Myclass24. The PDF includes detailed answers to all textbook questions, important diagrams with labels (Z-scheme, Calvin cycle), and chapter-wise summary notes. Students can access it offline anytime, making it a perfect resource for last-minute revision before boards or NEET. Check out NCERT Solutions for Class 11 Biology and NCERT Solutions for Class 11 for the rest of the chapters.
Photosynthesis in Higher Plants – Chapter Overview, Key Facts & Concepts
Photosynthesis in Higher Plants is a cornerstone chapter in Class 11 Biology that explains how green plants manufacture their own food using sunlight, carbon dioxide, and water. This chapter covers a wide range of concepts from the early experiments by scientists like Joseph Priestley and Jan Ingenhousz to the detailed biochemistry of the light and dark reactions. Here is everything you need to know about this chapter in a clear, concise, and mobile-friendly format.
Photosynthesis occurs primarily in the chloroplast, which contains the green pigment chlorophyll. The overall chemical equation of photosynthesis is: 6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O. It was Cornelis van Niel who first proposed that oxygen released during photosynthesis comes from water, not from carbon dioxide. This was a groundbreaking discovery that changed the way scientists understood the process.
The chapter is divided into two major stages. The Light Reactions take place in the thylakoid membranes of the chloroplast. They capture light energy and convert it into chemical energy in the form of ATP and NADPH. Photosystem I (PS I) has a reaction centre called P700, while Photosystem II (PS II) has P680. The electron flow in the light reactions follows the Z-scheme model proposed by Hill and Bendall.
The Dark Reactions or the Calvin Cycle take place in the stroma of the chloroplast. This cycle fixes CO2 into organic molecules and does not directly require light, though it depends on the products of the light reactions. The key enzyme here is RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase), the most abundant protein on Earth.
C4 plants like maize and sugarcane have a special mechanism to concentrate CO2 around RuBisCO, which minimises photorespiration. The C4 pathway involves two types of cells: mesophyll cells and bundle sheath cells. In contrast, CAM plants like cacti open their stomata at night to reduce water loss in hot, dry environments.
| Feature | C3 Plants | C4 Plants |
| First product of CO2 fixation | 3-PGA (3-carbon) | OAA (4-carbon) |
| Primary CO2 acceptor | RuBP | PEP |
| Photorespiration | High | Negligible |
| Example | Wheat, Rice, Sunflower | Maize, Sugarcane |
| Optimum temperature | 15–25°C | 30–45°C |
Pigments Involved in Photosynthesis
| Pigment | Colour | Function |
| Chlorophyll a | Blue-green | Primary photosynthetic pigment |
| Chlorophyll b | Yellow-green | Accessory pigment |
| Xanthophylls | Yellow | Accessory, protects chlorophyll |
| Carotenoids | Orange-yellow | Absorbs blue-violet light |
Photorespiration is a process where RuBisCO acts on oxygen instead of CO2, producing a 2-carbon compound that does not contribute to sugar synthesis. It is a wasteful process observed in C3 plants. C4 plants have evolved a mechanism to suppress this by concentrating CO2 in bundle sheath cells. The importance of this chapter extends to understanding food security, agricultural productivity, and climate change, making it one of the most application-oriented chapters in the NCERT Biology syllabus.
Key experiments to remember: Joseph Priestley (1770) showed that plants restore air used up by a burning candle; Jan Ingenhousz (1779) proved sunlight is essential; Julius von Sachs provided evidence for glucose production in leaves; and T.W. Engelmann used Spirogyra and bacteria to show that chloroplasts are the site of photosynthesis and red and blue light are most effective.