Types of Respiration in Plants

In plants respiration takes place in two ways, aerobic and anaerobic respiration. Let us study them in detail:

Aerobic Respiration

All eukaryotic organisms’ mitochondria do aerobic respiration. In the presence of oxygen, food molecules totally oxidize into carbon dioxide, water, and energy. All higher species exhibit this kind of respiration, which requires ambient oxygen. It includes the following 4-stages; 

Glycolysis ⇢ Oxidative decarboxylation ⇢ Kreb’s cycle ⇢ Electron Transport System

Anaerobic Respiration

The cytoplasm of prokaryotic organisms like yeast and bacteria is where this kind of respiration takes place. In this instance, less energy is released as a result of the food’s incomplete oxidation in the absence of oxygen. In anaerobic respiration, ethanol, and carbon dioxide are generated. It includes Glycolysis  ⇢ Fermentation. 

Also Read: Respiration

Glycolysis

The first stage of cellular respiration, which takes place in all organisms, is called glycolysis. The process by which glucose is broken down to provide energy is known as glycolysis. It generates two pyruvate molecules, ATP, NADH, and water. There is no need for oxygen throughout the process, which occurs in the cytoplasm of a cell. Both aerobic and anaerobic creatures experience it. The Krebs cycle comes after glycolysis during aerobic respiration. Small amounts of ATP are produced by the cells in the absence of oxygen as fermentation follows glycolysis.

Fermentation

In anaerobes, incomplete oxidation of glucose takes place in which the pyruvic acid is either converted into lactic acid or ethanol. However, fermentation does not yield any energy. So, the only energy generated is during the process of glycolysis. 

In human muscle cells during rigorous exercises due to lack of oxygen lactic acid is produced and in Yeast cells, ethanol and carbon-dioxide is generated. 

Oxidative Decarboxylation

In the case of aerobes, pyruvic acid produced during glycolysis enters the mitochondria where it is converted into Acetyl CoA in the presence of pyruvate dehydrogenase. This Acetyl CoA then further enters the Krebs cycle. 

Krebs Cycle

It is also called the tricarboxylic acid cycle or citric acid cycle. It begins with the Acetyl CoA condensate with oxaloacetic acid and water to form citric acid and ends with malic acid getting oxidized to regenerate the oxaloacetic acid to undergo the next cycle. 

Krebs cycle results in the generation of; 2 CO₂ molecules, 3 NADH₂ molecules, 1 FADH₂ molecule, and 1 GTP molecule. 

Electron Transport System

In the Electron Transport System step, the energy-containing electron passes through a chain of carrier complexes. It takes place in the inner mitochondrial membrane to activate the proton pump and then finally the oxidative phosphorylation of ADP takes place to form the ATP in the presence of oxygen which accepts the electron to generate water.

In plants, respiration is the mechanism through which energy for plant development is produced by combining oxygen and the sugars created during photosynthesis. Respiration contrasts photosynthesis in several ways. For survival in the natural world, plants make their own food. They create oxygen (O₂) and sugars (carbohydrates) from carbon dioxide (CO₂) in the atmosphere, which can then be used as an energy source. Respiration happens in the leaves, stems, and roots of the plant, whereas photosynthesis only occurs in the leaves and stems.

Table of Content

• Respiration in Plants
• Difference between Photosynthesis and Respiration
• Do Plants Breathe?
• Types of Respiration in Plants
• Glycolysis
• Fermentation
• Oxidative Decarboxylation
• Krebs Cycle
• Electron Transport System
• Respiratory Balance Sheet
• Amphibolic Pathway
• Respiratory Quotient
• FAQs on Respiration in Plants