Class 11 Biology - MAHARASHTRA
Respiration in Plants
The chapter Respiration in Plants explores how green plants break down complex food molecules to release energy essential for cellular activities. Students will study glycolysis, the Krebs cycle, electron transport system, and fermentation. Understanding cellular respiration is crucial for mastering plant physiology, metabolic pathways, and energy currency of the cell (ATP). In the Maharashtra State Board (MSBSHSE) Class 11 Biology exams, this chapter consistently contributes significant weightage, frequently featuring questions on pathway steps, enzyme locations, and the net yield of ATP, making it a high-scoring area for diligent students.
Start Learning FreeKey Concepts
Glycolysis (EMP Pathway)
The first phase of respiration occurring in the cytoplasm where one molecule of glucose is partially broken down into two molecules of pyruvic acid, yielding a net gain of 2 ATP and 2 NADH+H+ without using oxygen.
TCA Cycle (Krebs Cycle)
An aerobic pathway taking place in the mitochondrial matrix where acetyl-CoA is completely oxidized to carbon dioxide and water, producing NADH, FADH2, and substrate-level ATP.
Electron Transport System (ETS)
A series of coenzymes and cytochromes located on the inner mitochondrial membrane that transfer electrons, creating a proton gradient used by ATP synthase to produce ATP through oxidative phosphorylation.
Fermentation
An anaerobic process where pyruvic acid is converted into ethanol and carbon dioxide (alcoholic fermentation) or lactic acid by microbes and plant tissues when oxygen is absent.
Respiratory Quotient (RQ)
The ratio of the volume of CO2 evolved to the volume of O2 consumed during respiration, which helps determine the type of respiratory substrate being used (carbohydrates, fats, or proteins).
Important Formulas
Board Exam Info
In the Maharashtra State Board (MSBSHSE) Class 11 Biology examination, the chapter 'Respiration in Plants' typically carries about 4 to 6 marks with options. Common question types include diagrammatic representation of the Krebs cycle or glycolysis, differentiating between aerobic and anaerobic respiration, calculating net ATP yields, and defining Respiratory Quotient (RQ).
Frequently Asked Questions
What is the exact net gain of ATP from one glucose molecule during aerobic respiration?
A net gain of 36 or 38 ATP molecules is produced, depending on the shuttle system used to transport NADH from the cytoplasm into the mitochondria.
Where do glycolysis and the Krebs cycle occur in a plant cell?
Glycolysis takes place in the cytoplasm of the cell, whereas the Krebs cycle occurs inside the mitochondrial matrix.
Why is the Respiratory Quotient (RQ) for fats less than 1?
Fats require more oxygen for complete oxidation than the amount of carbon dioxide they release, resulting in an RQ value of less than 1 (typically around 0.7).
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