NEET Biology Lecture - Respiration in Plants

Introduction

• Plants also breathe but do not have specialized organs.
• Plants use stomata and lenticels for respiration.
• Each cell independently performs gaseous exchange, so specialized organs are not needed.

Types of Respiration

• Floating Respiration: Energy is obtained from the oxidation of fats and carbohydrates.
• Protoplasmic Respiration: Energy is obtained from the oxidation of proteins.

Types of Respiration (Based on Oxygen Presence)

• Aerobic Respiration: Occurs in the presence of oxygen.
• Anaerobic Respiration: Occurs in the absence of oxygen.

Overview of the Process

• Photosynthesis produces glucose.
• Oxidation of glucose occurs for energy.
• This is a catabolic process.

Major Stages

1. Glycolysis: Occurs in the cytoplasm, glucose is converted into pyruvate.
2. Link Reaction: Pyruvate is converted to Acetyl Coenzyme-A, occurs in mitochondria.
3. Krebs Cycle: Oxidation of Acetyl Coenzyme-A occurs in mitochondria.
4. Electron Transport Chain: ATP is produced in the inner mitochondrial membrane.

Notes:

• Glycolysis is independent of oxygen.
• Fate of Pyruvate: In the presence of oxygen, it goes into aerobic respiration, in absence, fermentation occurs.
• Types of Fermentation:
  • Alcoholic Fermentation: Produces ethanol and CO2.
  • Lactic Acid Fermentation: Produces lactic acid.
• The Electron Transport Chain uses the ATP synthase enzyme.

Balance Sheet

• Glycolysis: 2 ATP used, 4 ATP produced, net 2 ATP.
• Link Reaction: Production of NADPH2.
• Krebs Cycle: 36-38 ATP produced from one glucose molecule.

Important Questions

• How much ATP is produced from one glucose molecule?
• How many ATP are produced at the substrate-level with phosphoribosyl transferase?

Conclusion

• Plants respire for energy, and this process occurs in multiple stages.
• Understanding and implementing the process correctly can lead to success in the NEET exam.