Anaerobic Respiration Explained in Plants and Fungi

Respiration is a biological process in which energy is released from glucose to power cellular activities. It can occur in two forms: aerobic respiration, which requires oxygen, and anaerobic respiration, which takes place in the absence of oxygen.

Anaerobic respiration is less efficient than aerobic respiration because it produces less energy (ATP). However, it plays an important role in certain conditions where oxygen is limited, such as waterlogged soils for plants or fermentation processes in fungi.

Anaerobic Respiration in Plants

01. When Does It Occur?

Anaerobic respiration in plants usually happens when oxygen is scarce. This commonly occurs in:

• Waterlogged soils – Roots cannot obtain enough oxygen because water fills air spaces in the soil.
• Seed germination – Some seeds, such as rice, can start germinating in flooded conditions where oxygen is limited.
• Tissue damage – Wounded plant tissues may undergo anaerobic respiration temporarily.

02. Process of Anaerobic Respiration in Plants

1. Glycolysis – The breakdown of glucose into pyruvate occurs in the cytoplasm, releasing a small amount of ATP.
2. Fermentation – Pyruvate is converted into ethanol (alcohol) and carbon dioxide (CO₂) instead of undergoing complete oxidation. Let’s connect for our affordable Online GCSE Courses 

03. Chemical Equation for Anaerobic Respiration in Plants

C6H12O6→2C2H5OH+2CO2+Energy (ATP)C_6H_{12}O_6 \rightarrow 2C_2H_5OH + 2CO_2 + \text{Energy (ATP)}

(Glucose → Ethanol + Carbon Dioxide + Energy)

Effects of Anaerobic Respiration in Plants

• Short-term survival – It allows plants to generate energy when oxygen is unavailable.
• Ethanol accumulation – Over time, ethanol can build up in plant tissues and become toxic, potentially causing cell damage.
• Reduced growth – Since anaerobic respiration produces less ATP, plants may struggle to maintain normal growth and functions. Learn about Elastic Potential Energy 

Anaerobic Respiration in Fungi

01. When Does It Occur?

In fungi, anaerobic respiration is most commonly seen in yeast, a type of unicellular fungus. Yeast undergoes anaerobic respiration when oxygen is unavailable, particularly in fermentation processes.

02. Process of Anaerobic Respiration in Fungi (Yeast Fermentation)

1. Glycolysis – Glucose is broken down into pyruvate, releasing a small amount of ATP.
2. Alcoholic Fermentation – Pyruvate is converted into ethanol and carbon dioxide.

03. Chemical Equation for Anaerobic Respiration in Yeast

C6H12O6→2C2H5OH+2CO2+Energy (ATP)C_6H_{12}O_6 \rightarrow 2C_2H_5OH + 2CO_2 + \text{Energy (ATP)}

(Glucose → Ethanol + Carbon Dioxide + Energy)

Comparison of Anaerobic Respiration in Plants and Fungi

Feature	Plants	Fungi (Yeast)
Type of Fermentation	Alcoholic fermentation	Alcoholic fermentation
End Products	Ethanol, CO₂	Ethanol, CO₂
ATP Yield	Low (less than aerobic)	Low (less than aerobic)
Purpose	Temporary energy production in low-oxygen conditions	Fermentation for survival and industrial use
Harmful Effects	Ethanol accumulation can be toxic to plants	Useful for humans in food and drink industries

Differences Between Aerobic and Anaerobic Respiration

Aspect	Aerobic Respiration	Anaerobic Respiration
Oxygen Required?	Yes	No
Energy (ATP) Yield	High (36-38 ATP per glucose)	Low (only 2 ATP per glucose)
End Products	Carbon dioxide, water, energy	Ethanol (in plants and fungi), carbon dioxide, energy
Efficiency	More efficient	Less efficient
Location in Cell	Mitochondria	Cytoplasm

Conclusion

Anaerobic respiration is a vital process in both plants and fungi. In plants, it helps them survive temporarily in low-oxygen conditions but can be harmful if prolonged. In fungi, particularly yeast, anaerobic respiration is used to ferment alcohol and bread. Although anaerobic respiration is less efficient than aerobic respiration, it remains an important biological and industrial process. Enrol now for Online A level Courses