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What is Respiration?

Last updated date: 24th Feb 2024
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Define Respiration

Respiration is a process that occurs within cells to release energy through the breakdown of glucose molecules. Based on the use of oxygen, the process can be conveniently divided into two categories: aerobic and anaerobic respiration. It is a common misconception that humans and other multicellular organisms only use aerobic respiration. This is refuted by the fact that during vigorous exercise, our muscles undergo anaerobic respiration, producing lactic acid as a waste byproduct rather than carbon dioxide.

Types of Respiration

There are two kinds of breathing; they are as follows.

What is Respiration in Plants? There are two types of Respiration in Plants which are as follows:

Aerobic Respiration in Plants

Respiration produces energy in the presence of oxygen. It is a continuous process that occurs within animal and plant cells. The following chemical equation can be used to explain this process:

Glucose+ Oxygen → Carbon dioxide + Water + Energy

Anaerobic Respiration in Plants

In the absence of oxygen, respiration generates energy. The anaerobic respiration chemical equation is:

Glucose → Alcohol + Carbon dioxide + Energy (ATP )

Anaerobic Respiration is also known as fermentation.

Steps of Respiration in Organisms

Respiration in Organisms

Respiration in Organisms

The first step of respiration in organisms is glycolysis. It converts one glucose molecule into two pyruvate molecules, yielding two molecules of ATP in total. This occurs in the cytosol.

The pyruvate then enters the mitochondria and is oxidised to acetyl CoA, which enters the Krebs cycle (citric acid cycle). The process takes place in the mitochondrial matrix. The third stage occurs on the inner membrane of mitochondria. It's known as oxidative phosphorylation. Chemical energy is converted during this stage and used to synthesise ATP.

What is Respiration and Breathing in Plants:

Plants require oxygen to respire, and the process emits carbon dioxide. Unlike humans and animals, plants lack specialised structures for gas exchange; however, they have stomata (found in leaves) and lenticels (found in stems) that are actively involved in gas exchange. In addition, plant leaves, stems, and roots respire slower than humans and animals.

Breathing is not the same as respiration. Both animals and humans breathe, which is a step in the respiration process. Plants breathe throughout their lives because the plant cell requires energy to survive. Plants, on the other hand, breathe in a unique way known as cellular respiration.

Plants generate glucose molecules in this process of cellular respiration by capturing and converting sunlight energy into glucose. Several live experiments demonstrate plant respiration. All plants respire to provide power to their cells, allowing them to be active or alive.

Plant Respiration Process

Plant Respiration Process

Solved Examples

1. Which of the following gases is discharged during the respiration process?

(a) Oxygen   

(b) Hydrogen   

(c) Carbon dioxide

Ans: (c) Carbon dioxide.

2. All organisms are composed of small microscopic units that cannot be seen with the naked eye and are referred to as____.

(a) animals 

(b) cells 

(c) tissues

Ans: (b) cells

3. Identify the type of breathing that causes muscle cramps.

(a) Aerobic respiration  

(b) Anaerobic respiration

Ans: (b) Anaerobic respiration


The use of oxygen in the process of cellular respiration is the primary distinction between aerobic and anaerobic respiration. Anaerobic respiration is similar to aerobic respiration, except that it occurs without oxygen. As a result, this process produces lactic acid and ATP as byproducts.

FAQs on What is Respiration?

1. What exactly is respiration(What is respiration short answer)?

Respiration is a metabolic procedure that occurs in all living organisms. There is air movement in and out of the lungs during this process.

2. Write two categories of respiration?

Aerobic respiration occurs in the presence of oxygen, whereas anaerobic respiration appears when there is no oxygen present.

3. What is the fundamental equation governing aerobic cellular respiration?

Aerobic cellular respiration is described by the equation

 C6H12O6 + 6O2 ————-> 6H2O + 6CO2 + ATP

4. What are the different kinds of anaerobic respiration?

Anaerobic respiration is classified into two types:

  • Fermentation of alcohol

  • Fermentation of lactic acid.

5. Identify the various stages of aerobic respiration.

Aerobic cellular respiration has the following stages:

  • Glycolysis

  • The Krebs cycle

  • Oxidative phosphorylation