Class 11 Biology - WEST-BENGAL
Respiration in Plants
The chapter 'Respiration in Plants' in Class 11 Biology explores how plants break down complex organic compounds, primarily glucose, to release energy essential for cellular activities. For WBBSE students, mastering this chapter is crucial as it details the critical biochemical pathways involved in cellular respiration, including Glycolysis, the Krebs cycle, and the Electron Transport System. You will learn the difference between aerobic and anaerobic respiration, the significance of the respiratory quotient (RQ), and how ATP acts as the energy currency of the cell. Thorough understanding of these metabolic pathways is essential for scoring well in both objective and descriptive board exam questions.
Start Learning FreeKey Concepts
Glycolysis (EMP Pathway)
The first phase of cellular respiration that occurs in the cytoplasm, where one molecule of glucose is partially oxidized into two molecules of pyruvic acid without requiring oxygen.
Krebs Cycle (Tricarboxylic Acid Cycle)
An aerobic pathway taking place in the mitochondrial matrix where acetyl-CoA is completely oxidized to carbon dioxide, producing NADH, FADH2, and substrate-level ATP.
Electron Transport System (ETS) and Oxidative Phosphorylation
A series of coenzymes and cytochromes located in the inner mitochondrial membrane that transfer electrons from NADH and FADH2 to oxygen, driving ATP synthesis via a proton gradient.
Fermentation (Anaerobic Respiration)
A process occurring in the absence of oxygen where pyruvic acid is converted into ethyl alcohol and carbon dioxide or lactic acid, yielding very little energy.
Respiratory Quotient (RQ)
The ratio of the volume of carbon dioxide evolved to the volume of oxygen consumed during respiration, which helps determine the type of respiratory substrate being used.
Important Formulas
Board Exam Info
In the West Bengal Council of Higher Secondary Education (WBBSE) Class 11 Biology examination, this chapter typically carries around 4 to 6 marks. Questions often include short-answer questions (SAQs), multiple-choice questions (MCQs), and descriptive questions (LAQs) such as explaining the steps of glycolysis, the Krebs cycle, or differentiating between aerobic and anaerobic respiration.
Frequently Asked Questions
What is the net gain of ATP molecules from one glucose molecule during aerobic respiration?
The net gain is typically 38 ATP molecules in prokaryotes and certain eukaryotic tissues via the malate-aspartate shuttle, though it is often considered 36 ATP in most eukaryotic cells due to the cost of transporting NADH into the mitochondria.
Where do glycolysis and the Krebs cycle take place inside the plant cell?
Glycolysis takes place in the cytoplasm of the cell, while the Krebs cycle occurs inside the mitochondrial matrix.
Why is the respiratory quotient (RQ) for fats and proteins less than 1?
RQ is less than 1 because fats and proteins require more oxygen for their oxidation relative to the amount of carbon dioxide they produce compared to carbohydrates.
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