Respiration in Plants – CHEMASH Biology

Respiration in plants is the process by which glucose is broken down to release energy in the form of ATP. This chapter is very important for Class 11 Biology, Boards & NEET 2026.

Related Topics: Photosynthesis | Enzymes & Metabolism | Biomolecules

Introduction
Types of Respiration
Glycolysis
Krebs Cycle
Electron Transport Chain
Aerobic vs Anaerobic
MCQs
FAQs

Introduction

Respiration is a catabolic process where complex organic molecules (like glucose) are oxidized to release energy. The energy is stored in ATP molecules.

Overall Equation (Aerobic Respiration):

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)

Types of Respiration

Aerobic Respiration: Requires oxygen
Anaerobic Respiration: Occurs without oxygen

Glycolysis

Occurs in cytoplasm. Glucose (6C) breaks into two molecules of pyruvate (3C).

Net gain: 2 ATP
Produces NADH
Does not require oxygen

Krebs Cycle (Citric Acid Cycle)

Occurs in mitochondrial matrix. Pyruvate is further oxidized to produce CO₂, NADH, FADH₂ and ATP.

Electron Transport Chain (ETC)

Occurs in inner mitochondrial membrane. Electrons from NADH & FADH₂ pass through carriers to produce large amount of ATP.

Major ATP production occurs here.

Aerobic vs Anaerobic Respiration

Feature	Aerobic	Anaerobic
Oxygen	Required	Not required
ATP Produced	36-38 ATP	2 ATP
End Products	CO₂ + H₂O	Ethanol or Lactic Acid

MCQs with Explanation (NEET 2026)

1. Glycolysis occurs in:
Answer: Cytoplasm
Explanation: First stage of respiration.

2. Maximum ATP is produced in:
Answer: Electron Transport Chain
Explanation: Oxidative phosphorylation occurs here.

3. End product of anaerobic respiration in plants:
Answer: Ethanol + CO₂

4. Krebs cycle occurs in:
Answer: Mitochondrial matrix

FAQs

Q1. Do plants respire at night?
A: Yes, respiration occurs continuously day and night.

Q2. What is the energy currency of cell?
A: ATP.

Official syllabus reference: NCERT Biology Textbook

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Respiration in Plants