NCERT Exemplar Solutions for Class 11 Biology Chapter 14 Respiration in Plants
The NCERT Exemplar Solutions for Class 11 Biology Chapter 14, Respiration in Plants, help students understand how plants break down glucose and other molecules to release energy required for various life processes. Unlike photosynthesis, which stores energy, respiration releases it in the form of ATP (adenosine triphosphate). This chapter explains glycolysis, the citric acid cycle, the electron transport chain, fermentation, and respiratory balance. NCERT Exemplar questions focus on application-based learning, testing students’ ability to analyze concepts beyond simple memorization. The chapter begins with the introduction to respiration, defining it as a catabolic process involving the oxidation of food molecules to release energy. Exemplar questions often ask students to differentiate between aerobic and anaerobic respiration and to explain why ATP is called the energy currency of the cell.
Glycolysis is the first step in respiration, occurring in the cytoplasm. Here, one molecule of glucose is broken down into two molecules of pyruvate, with a net gain of 2 ATP and 2 NADH molecules. Exemplar questions frequently include step-wise reactions of glycolysis, enzymes involved, and its universal presence in both aerobic and anaerobic organisms.
The Krebs cycle or citric acid cycle is explained as the central pathway of respiration, taking place in the mitochondrial matrix. Pyruvate is converted into acetyl-CoA, which enters the cycle, producing NADH, FADH2, ATP, and releasing CO2. Exemplar questions often test knowledge of intermediates like citrate, α-ketoglutarate, and oxaloacetate, as well as the overall energy yield.
Next, the Electron Transport System (ETS) is covered in detail. Located in the inner mitochondrial membrane, the ETS uses electrons carried by NADH and FADH2 to produce ATP through oxidative phosphorylation. Oxygen acts as the final electron acceptor, forming water. Exemplar problems usually ask students to explain chemiosmotic theory, the role of ATP synthase, and the differences between oxidative and substrate-level phosphorylation. The chapter also explains anaerobic respiration and fermentation, where energy is released without oxygen. In plants and yeast, pyruvate is converted to ethanol and CO2, while in muscle cells, it forms lactic acid. Exemplar questions focus on comparing energy yield in aerobic vs anaerobic respiration and practical applications like alcohol production and dough fermentation.
Another important concept is the Respiratory Quotient (RQ), the ratio of CO2 evolved to O2 consumed. Exemplar questions may involve numerical problems, asking students to calculate RQ for carbohydrates, fats, and proteins, highlighting differences in substrate utilization. The chapter also emphasizes the amphibolic nature of respiration, showing how respiratory pathways are interconnected with anabolic processes such as amino acid and fatty acid synthesis. Exemplar questions test the ability to relate respiration to overall metabolism. To prepare well, students should study the flowcharts of glycolysis,the Krebs cycle, and ETS provided in the NCERT textbook. These diagrams are often the basis for Exemplar problems. Practicing Exemplar questions sharpens analytical skills and helps students tackle both direct and reasoning-based exam questions confidently. In conclusion, NCERT Exemplar Solutions for Class 11 Biology Chapter 14 Respiration in Plants provide a clear and systematic understanding of how plants release and utilize energy. By solving these Exemplar questions, students not only strengthen their theoretical base but also build strong problem-solving skills for board and competitive exams.