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Cellular Respiration and Energy Production in Cells

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Cellular respiration equation stages and ATP yield explained

Respiration in a living being is one of the fundamental processes that ensure their survival. To survive, we need energy, and breathing makes sure we receive the required energy while performing any work.

For instance, when you are trying to lift a heavy bag or running to catch a bus or even reading a book. All these functions require energy in different amounts, which is provided to our muscles and other body parts through respiration. This helps us in performing the work, and it functions at the cost of energy produced from the food that you intake.

Look at the picture below. It shows two different processes of breathing involved in regular respiration.

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Students often query about what is internal respiration.Notably, it has the same objective as cellular respiration. Both are similar and responsible for providing energy to the body to perform a specific task.

Internal Respiration - A Detailed Overview

Respiration is the primary function that is carried out in a living body. As mentioned already, it provides adequate energy supply to the body while working. In biological terms, a body is composed of cells, and they require energy to work.

Be it the growth of the body or performance of essential functions, cells are active at all times. This is what is the function of cellular respiration, as it helps in the diffusion of oxygen into the blood. 

Students have to understand that there are two basic types of respiration - internal and external. As the names imply, the latter indicates respiration or exchange of gases with lungs and other tissues that are in direct contact with the external environment. 

Distinction Between Types of Respiration

It must be clear by now that there are three kinds of respiration, of which two more or less come under the same category. These are  -

  • Internal respiration

  • External respiration

  • Cellular respiration

Out of these, both internal and cellular respiration occurs at the cellular level. On the other hand, external respiration takes place between the external environment and tissues that are directly involved, such as the lungs.

Thus, it is clear that external respiration is the regular breathing that you do. You inhale oxygen and exhale carbon dioxide, which is termed as external respiration. However, to know about cellular respiration class 10, students have to get through the basic distinction among all these types of respiration.

What is Cellular Respiration?

The respiration occurring at the cellular level wherein the cells produce energy by combining oxygen with food molecules is called cellular respiration. Refer to the image below for a quick overview of the process taking place during this respiration.

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The image shows that both glucose and oxygen combine to form carbon dioxide and water. Here, you can understand that the oxygen taking part in cellular respiration is the oxygen that you inhaled through external respiration.

You can also refer to the chemical equation for advanced learning. Equations help in fetching higher grades in the exam. Make sure to include the same while writing your answer in the exam. 

How often Does the Body Perform Cellular Respiration

Cellular respiration helps in providing the body with energy to carry out regular tasks. Therefore, it is evident that in order to survive, cellular respiration has to take place at times. 

In simple words, the cells turn the food that you intake into energy. Look at the image below for clarity. It shows how the food is produced by photosynthesis. It is followed by breaking down of this food by the cell (mitochondria) to release energy (ATP).

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To know more about what is internal respiration, you can refer to our online learning programs. You can get access to high quality study materials drafted by subject experts. Also, you can download our Vedantu app for enhanced learning and convenient access to these detailed study materials and online sessions.

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FAQs on Cellular Respiration and Energy Production in Cells

1. What is cellular respiration?

Cellular respiration is the metabolic process by which cells break down glucose to produce ATP (adenosine triphosphate), the main energy currency of the cell.

  • It occurs in both plant and animal cells.
  • It usually requires oxygen in aerobic respiration.
  • The overall equation is: glucose + oxygen → carbon dioxide + water + ATP.
This process provides energy for growth, movement, repair, and other life functions.

2. Where does cellular respiration occur in the cell?

Cellular respiration mainly occurs in the mitochondria, known as the powerhouse of the cell.

  • Glycolysis takes place in the cytoplasm.
  • The Krebs cycle occurs in the mitochondrial matrix.
  • The electron transport chain is located on the inner mitochondrial membrane.
In prokaryotic cells, these processes occur in the cytoplasm and across the plasma membrane.

3. What are the main stages of cellular respiration?

The three main stages of cellular respiration are glycolysis, the Krebs cycle, and the electron transport chain.

  • Glycolysis: Breaks glucose into pyruvate and produces a small amount of ATP.
  • Krebs cycle: Releases carbon dioxide and transfers energy to electron carriers.
  • Electron transport chain: Produces most ATP using oxygen.
Together, these stages maximize ATP production from one glucose molecule.

4. What is the difference between aerobic and anaerobic respiration?

The main difference between aerobic and anaerobic respiration is that aerobic respiration uses oxygen, while anaerobic respiration does not.

  • Aerobic respiration: Produces up to 36–38 ATP per glucose; occurs in mitochondria.
  • Anaerobic respiration: Produces only 2 ATP per glucose; occurs in cytoplasm.
  • End products differ: carbon dioxide and water (aerobic) vs. lactic acid or ethanol (anaerobic).
Aerobic respiration is more efficient in energy production.

5. How much ATP is produced in cellular respiration?

Cellular respiration produces approximately 36–38 ATP molecules from one molecule of glucose during aerobic respiration.

  • 2 ATP from glycolysis
  • 2 ATP from the Krebs cycle
  • 32–34 ATP from the electron transport chain
The exact number may vary depending on cell type and efficiency.

6. What is the role of oxygen in cellular respiration?

Oxygen acts as the final electron acceptor in the electron transport chain during aerobic respiration.

  • It combines with electrons and hydrogen ions to form water.
  • This allows continuous flow of electrons through the chain.
  • Without oxygen, ATP production drops significantly.
Oxygen is therefore essential for maximum ATP yield in most organisms.

7. What is glycolysis and why is it important?

Glycolysis is the first step of cellular respiration that breaks one glucose molecule into two pyruvate molecules.

  • Occurs in the cytoplasm.
  • Produces 2 ATP and 2 NADH.
  • Does not require oxygen.
Glycolysis is important because it begins glucose breakdown and supplies intermediates for further ATP production.

8. What is the Krebs cycle in cellular respiration?

The Krebs cycle, also called the citric acid cycle, is a series of reactions that release energy from acetyl-CoA in the mitochondria.

  • Occurs in the mitochondrial matrix.
  • Produces carbon dioxide as a waste product.
  • Generates NADH and FADH₂ for the electron transport chain.
It plays a central role in extracting high-energy electrons for ATP production.

9. How is cellular respiration related to photosynthesis?

Cellular respiration and photosynthesis are complementary processes in the carbon and energy cycle.

  • Photosynthesis uses carbon dioxide and water to produce glucose and oxygen.
  • Cellular respiration uses glucose and oxygen to produce carbon dioxide and water.
  • The products of one process are the reactants of the other.
This relationship maintains energy flow and gas balance in ecosystems.

10. Why is cellular respiration important for living organisms?

Cellular respiration is important because it produces ATP, the energy required for all cellular activities.

  • Supports muscle contraction and movement.
  • Enables active transport across membranes.
  • Powers biosynthesis of proteins, DNA, and other molecules.
Without cellular respiration, cells would not have enough usable energy to sustain life processes.


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