What Are the Main Steps of Cellular Respiration?
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.
FAQs on Cellular Respiration: Process, Importance & Stages
1. What is the primary purpose of cellular respiration in a living organism?
The primary purpose of cellular respiration is to break down organic compounds, such as glucose, in a controlled, stepwise manner to release energy. This released energy is then captured and stored in the form of Adenosine Triphosphate (ATP) molecules, which serve as the main energy currency for all cellular activities.
2. What is the complete balanced equation for aerobic cellular respiration?
The overall chemical equation for the aerobic respiration of one molecule of glucose is: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP). This equation shows that glucose and oxygen are the reactants, while carbon dioxide, water, and energy are the products.
3. What are the main stages of aerobic respiration and where do they occur within a eukaryotic cell?
Aerobic respiration is a complex process divided into three main stages, each occurring in a specific location within the cell:
- Glycolysis: This initial stage occurs in the cytoplasm and involves the breakdown of glucose into two molecules of pyruvate.
- Krebs Cycle (or Citric Acid Cycle): This stage takes place in the mitochondrial matrix, where pyruvate is further oxidized.
- Electron Transport Chain (ETC) and Oxidative Phosphorylation: This final stage occurs on the inner mitochondrial membrane, where the majority of ATP is synthesised.
4. How does cellular respiration differ from the process of breathing?
Cellular respiration and breathing are related but distinct processes. Breathing (or physiological respiration) is a physical process of gas exchange—inhaling oxygen from the atmosphere and exhaling carbon dioxide. In contrast, cellular respiration is a biochemical process that occurs inside the cells to produce ATP by breaking down food molecules, using the oxygen supplied by breathing.
5. What is the fundamental difference between aerobic and anaerobic respiration?
The fundamental difference lies in the presence or absence of oxygen. Aerobic respiration requires oxygen as the final electron acceptor in the Electron Transport Chain and produces a large amount of ATP (around 36-38 molecules per glucose). Anaerobic respiration occurs in the absence of oxygen, resulting in incomplete breakdown of glucose and yielding a much smaller amount of ATP (typically 2 molecules per glucose).
6. How are photosynthesis and cellular respiration related to each other?
Photosynthesis and cellular respiration are complementary biochemical processes. Photosynthesis, which occurs in plants and some other organisms, captures light energy to build glucose (C₆H₁₂O₆) from carbon dioxide and water. Cellular respiration, which occurs in most living things, breaks down that glucose to release chemical energy (ATP), producing carbon dioxide and water as byproducts. In essence, the products of one process are the reactants of the other, forming a critical energy cycle in ecosystems.
7. Why is ATP known as the 'energy currency' of the cell?
ATP is called the energy currency because it stores chemical energy released from the breakdown of food in a usable, transportable form. The energy held in the high-energy phosphate bonds of ATP can be easily released to power thousands of cellular reactions, such as muscle contraction, active transport, and synthesis of molecules. This makes ATP a universal and readily available energy source for the cell, much like currency is used for economic transactions.
8. Can cells perform cellular respiration using molecules other than glucose?
Yes, cells are highly versatile and can use other organic molecules for energy. Fats (lipids) are broken down into glycerol and fatty acids, which can enter the respiratory pathway at different points like glycolysis and the Krebs cycle. Similarly, proteins can be broken down into amino acids, which are then converted into intermediates that can also enter the Krebs cycle. While glucose is the preferred substrate, these alternative pathways ensure the cell has a continuous energy supply.
