Cellular Respiration: Organelles, Location & Responsibilities

Brittany W., Jeremy Battista
  • Author
    Brittany W.

    Brittany has a bachelor's degree in biological sciences and biochemistry.

  • Instructor
    Jeremy Battista

    Jeremy has a master of science degree in education.

Learn about cellular respiration. Identify organelles where cellular respiration occurs, and study a diagram of which organelles perform cellular respiration. Updated: 11/18/2021

How Does Cellular Respiration Take Place?

Cellular respiration is a series of biochemical pathways used to convert food into available energy for the cell. A pathway is a series of reactions that work together to produce a common goal. The goal of cellular respiration is to produce energy in the form of adenosine triphosphate (ATP). ATP is the premier energy molecule of the cell because it contains enough energy within its bonds to drive multiple biochemical reactions forward.

Cellular respiration consists of the following pathways:

  • Glycolysis: Glucose (sugar) is converted into a molecule called pyruvate.
  • Pyruvate oxidation: Pyruvate is converted into a molecule called acetyl-CoA.
  • The Krebs cycle: Also known as the citric acid cycle. Acetyl-CoA is converted into citric acid, hence the name. Citric acid is then used to produce a collection of high-energy intermediates.
  • Electron transport chain: The high-energy intermediates formed from the citric acid cycle are used to create an electrochemical gradient. An electrochemical gradient is an accumulation of electric energy (protons in this case) on one side of a membrane or biological partition.
  • Chemiosmosis: The energy accumulated from the electrochemical gradient is used to power ATP synthesis.
  • ATP synthesis: ATP is synthesized using both electrical and mechanical energy. The electrical energy comes from the electrochemical gradient. The mechanical energy comes from the motor-like action of the enzyme ATP synthase.

Enzymes are proteins that help biochemical reactions occur. Some sources consider pyruvate oxidation the first step of the citric acid cycle. Others consider it as a separate reaction that links glycolysis and the citric acid cycle together. The electron transport chain and chemiosmosis are collectively known as oxidative phosphorylation. This is because adenosine diphosphate (ADP) is phosphorylated (receives a phosphate molecule) in the presence of oxygen to become ATP.

Because cellular respiration occurs in the presence of oxygen, it is also known as aerobic cellular respiration. This is in stark contrast to anaerobic respiration, also known as fermentation. Anaerobic respiration is the conversion of glucose to lactic acid in the absence of oxygen. Anaerobic respiration provides a way for organisms to create a small amount of ATP even when the body is unable to generate sufficient oxygen levels.

In what organelle does cellular respiration take place? Cellular respiration takes place in multiple areas of the cell; however, it primarily occurs in the mitochondrion.

Cellular Respiration

Cellular respiration refers to a series of metabolic reactions that occur inside of a cell. The product of respiration is adenosine triphosphate (ATP), which is the molecule that our bodies use as energy. It is an exothermic oxidation/reduction reaction, which just means that it gives off heat.

In aerobic (with oxygen) respiration, there is a series of cycles and processes that occur almost simultaneously. Glycolysis occurs first, where a molecule of glucose gets broken down into four molecules of ATP, absorbing two for use later; the other two are products.

Occurring at the same time is the Krebs Cycle, otherwise known as the citric acid cycle, where carbon dioxide is created, as is reduced nicotinamide adenine dinucleotide (NADH), which is another energy molecule. Finally, oxidative phosphorylation occurs, which uses the NADH in the electron transport chain to produce water as a waste product. All in all, 32 molecules of ATP are created via respiration in each cell.

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Cellular Respiration Organelle

In what organelle does cellular respiration occur? As mentioned, cellular respiration occurs in multiple areas throughout the cell. However, the main cellular respiration organelle is the mitochondrion. An organelle is a structure that performs a specific job within the cell. The mitochondrion is most notable for its role in energy production because the majority of ATP is produced within its membranes. The mitochondrion contains:

  • An outer membrane
  • An inner membrane with cristae (folds)
  • A matrix: the innermost portion of the mitochondrion

In cellular respiration, pyruvate oxidation and the Krebs cycle occur in the mitochondrial matrix (3.2). Oxidative phosphorylation and ATP synthesis occur in and across the inner mitochondrial membrane (3.11).

The anatomy of the mitochondrion.

The organelles involved in cellular respiration include:

  • Cytoplasm: Though technically not an organelle, the cytoplasm serves as a backdrop for many biochemical reactions. It is a thick solution that contains everything within the cellular membrane.
  • Mitochondrion: The majority of cellular respiration either occurs in the mitochondrial matrix or across the inner mitochondrial membrane. Cristae increase the membrane's surface area and make room for more reactions. More reactions equate to more ATP production.
  • Ribosomes: Proteins are made in organelles called ribosomes. While ribosomes are not directly involved in ATP production, they are certainly responsible for making the enzymes that perform the reactions that make ATP.

The reactions of cellular respiration occur in the cytoplasm (11) and in the mitochondrion (9).

The anatomy of an animal cell.

In What Organelle Does Cellular Respiration Occur?

What organelle is responsible for cellular respiration? As discussed, cellular respiration primarily occurs in the mitochondrion. To clarify which organelle performs cellular respiration, would be to include the cytoplasm (though technically not an organelle), the mitochondrion, and ribosomes.

Which reaction of cellular respiration occurs in which organelle?

Organelles Involved

The main organelle involved in respiration is the mitochondria. It's known as the powerhouse of the cell due to the fact that 32 ATP are created from this organelle. The entire process of cellular respiration occurs in multiple simultaneous steps, but they almost all occur in different parts of the mitochondria, with the exception of glycolysis.

Glycolysis occurs in the cytoplasm of the cell. The cytoplasm, if you recall, includes the cytosol, the water based solution of salt and nutrients, and the organelles that reside within it. It is in this substance where glycolysis happens, eventually transferring the pyruvate that is produced into the mitochondria where it is used in the next process.

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Video Transcript

Cellular Respiration

Cellular respiration refers to a series of metabolic reactions that occur inside of a cell. The product of respiration is adenosine triphosphate (ATP), which is the molecule that our bodies use as energy. It is an exothermic oxidation/reduction reaction, which just means that it gives off heat.

In aerobic (with oxygen) respiration, there is a series of cycles and processes that occur almost simultaneously. Glycolysis occurs first, where a molecule of glucose gets broken down into four molecules of ATP, absorbing two for use later; the other two are products.

Occurring at the same time is the Krebs Cycle, otherwise known as the citric acid cycle, where carbon dioxide is created, as is reduced nicotinamide adenine dinucleotide (NADH), which is another energy molecule. Finally, oxidative phosphorylation occurs, which uses the NADH in the electron transport chain to produce water as a waste product. All in all, 32 molecules of ATP are created via respiration in each cell.

Organelles Involved

The main organelle involved in respiration is the mitochondria. It's known as the powerhouse of the cell due to the fact that 32 ATP are created from this organelle. The entire process of cellular respiration occurs in multiple simultaneous steps, but they almost all occur in different parts of the mitochondria, with the exception of glycolysis.

Glycolysis occurs in the cytoplasm of the cell. The cytoplasm, if you recall, includes the cytosol, the water based solution of salt and nutrients, and the organelles that reside within it. It is in this substance where glycolysis happens, eventually transferring the pyruvate that is produced into the mitochondria where it is used in the next process.

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