Difference Between Anabolism and Catabolism

Edited by Diffzy | Updated on: May 28, 2023


Difference Between Anabolism and Catabolism

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We, humans, love what? Any guesses Food! The necessity for humans to survive. The substance is ingested and assimilated by the cells of the body to provide energy, maintain life, or stimulate growth. The chemical reactions in the body cells that change food into energy are called metabolism. It is broadly divided into two types: Anabolism and Catabolism.

Anabolism vs Catabolism

Under this category, one makes complex molecules from simpler ones, while the other breaks large molecules into smaller ones. Under Anabolism, a series of reactions produce biomolecules needed to function. On the contrary, catabolism is spontaneous and thermodynamically favourable.

Anabolism is a biochemical reaction that synthesizes molecules from smaller components, reactions are endergonic which means they are not spontaneous. These reactions require ATP (Adenosine Triphosphate), which gets hydrolyzed and powers several anabolic reactions. The anabolic hormones help this process to occur. Insulin, which facilitates glucose absorption, and anabolic steroids, which enhance muscular growth; are some examples of anabolic hormones. Anabolic activity is a kind of anaerobic exercise that also produces muscle strength and mass.

Under Catabolism, a series of biochemical reactions split complex molecules into simpler ones that later generate energy for anabolism. Additionally, the process is exergonic, which works through oxidation and hydrolysis. Adrenaline, glucagon, cortisol, melatonin, hypocretin, and cytokines are catabolic hormones. Cells often store complex components and raw materials; catabolism breaks these down to produce new products.

Difference between Anabolism and Catabolism in tabular form

Parameters of comparisonAnabolismCatabolism
DefinitionIn this process, complex molecules build from simpler molecules.In this process, complex molecules break down into simpler molecules.
EnergyEnergy gets stored in the process.Energy releases in the process.
Reaction typeThe reaction type is endothermic. This process is where the heat is stored.The reaction type is exothermic. This process is where the heat is released.
StorageIn this process, new molecules synthesise to store energy and use this energy later.In this process, stored molecules produce ATP (Adenosine Triphosphate).
UseAnabolism is responsible for the repair and growth of tissues.Catabolism is responsible for the most vital currency in our body, i.e., ATP (Adenosine triphosphate).
ProcessUnder this process, molecules build, and energy is stored. It is constructive.Under this process, molecules break down, and energy is released. It is destructive.
Type of process (in terms of energy)Under this process, energy stores; it is endergonic.Under this process, energy releases; it is exergonic.
Chemical BondsChemical bonds form in this process, so energy is supplied.Chemical bonds break in this process, so energy is released.
ExamplesExamples include protein synthesis, DNA replication, and glycogen formation.Examples include cellular respiration, digestion of food and breakdown of muscle tissue.


Under this process, smaller units constructs to form complex molecules. The process involves a lot of metabolic processes. Metabolism divides into two parts, where Anabolism is the building part.

Anabolism goes through a series of polymerization reactions, where monomers go through condensation reactions to form macromolecules. Some macromolecules formed are proteins, nucleic acids, and polysaccharides. They take the help of enzymes and cofactors to carry out the process.

Energy Source

To carry out the anabolic reaction, energy needs to be supplied. This type of process is known as the endergonic process. In this process, energy is made from the cleavage of ATP (Adenosine Triphosphate). It involves reduction and entropy decreases, which makes the anabolic process unfavourable.

This links up with Gibb’s free energy. This process absorbs heat from the surroundings which makes it unfavourable from the thermodynamic point of view. The process is also non-spontaneous. Gibb’s free energy is positive in this case, so the driving force must be extracted from the surroundings. Under constant pressure and temperature, the Gibbs free energy is positive as entropy is negative.


The process is also stabilized by entropy, where energy is not present. In those cases, the formation of the phospholipid layer is seen, supported by hydrophobic interactions.


Cofactors like NADH, NADPH, and  FADH2 are used to reduce the ATP (Adenosine Triphosphate). They are the electron carriers in this process. And other metal ions present under enzymes are used to stabilize the functional groups or substrates.


Substates are those substances in anabolic reactions, which are intermediates taken from catabolic processes, at the time of excessive energy conditions.

Functions of Anabolism

Anabolism has a lot of functions and some of them are-

  1. Growth and Repair- It involves the growth of new tissues and the repair of damaged ones. Some examples are the growth of new muscle tissue, repair of fractured bones, and healing of wounds.
  2. Energy storage- As stated above, they take energy from the surroundings to carry out the task. It stores energy in the form of glycogen and triglycerides (complex molecules). Though later those molecules are broken down to get energy for carrying out other processes.
  3. Hormone synthesis- one of the most vital tasks carried out through anabolic reactions is the synthesis of hormones. Hormones regulate functions like metabolism, reproduction, and growth, by working as chemical messengers in the body.
  4. Protein synthesis- It also synthesizes proteins in our body, which are responsible for biological processes in our body. Some of them are the contraction of muscles, catalysis of enzymes and boosting the immune system.
  5. Nucleic Acid synthesis- Not only it stores energy to be used by the body, but it also produces substances that store genetic information in the body. The substances are nucleic acids like DNA and RNA.
  6. Carbohydrate synthesis- It also produces substances that get stored in livers and muscles, later synthesized as energy. These substances are carbohydrates like glycogen and so on.
  7. Lipid synthesis- It also produces components, vital for cell membranes. Those components are triglycerides and phospholipids.


Anabolism undergoes irreversible steps at phases due to enzymes from catalysis. It helps the cell to regulate the rate and continue in an infinite loop. It is known as a futile cycle.

This creates a balance between anabolism and catabolism, where the whole process is dependent upon ADP (Adenosine diphosphate) and ATP (Adenosine triphosphate), which is called the energy of the cell. If the amount of ATP is high then the cells prefer the anabolic path and if the amount of ADP is high then the cells prefer the catabolic path. Both processes are interconnected to each other. And without one other cannot exist. The body stays regulated when it goes through these multiple pathways.


Catabolism is a process, under which a molecule breaks down into units, which get oxidized to release energy or might be used in anabolic reactions. The breaking down of larger molecules (polysaccharides, amino acids, and nucleic acids) into smaller ones (fatty acids, amino acids, and monosaccharides) goes through several metabolic pathways. This stage of metabolism is known as the breaking-down aspect.

The broken-down polymers are either used in anabolic process (constructing new molecules) or degrading the monomers more into simple products, to release energy. Multiple cellular wastes like lactic acid, carbon dioxide, ammonia, and urea. If the formation takes place, then it is an oxidation process, that involves the release of free energy, some might get lost as heat, but the rest is used to synthesize ATP (Adenosine Triphosphate). And as we know, by the principle of conservation of energy, i.e., energy can neither be created nor be destroyed, it just transfers from one form to another. So, the same happens inside the cell, where the molecule breaks up to release energy, and the same energy is transferred to make up anabolic reactions.

Three stages of catabolism:

Stage 1

Digestion- It is the simplest of all the stages. The function of this stage simply matches the definition of Catabolism. In this stage, large molecules break down into smaller molecules. This stage takes place in the digestive system with the help of enzymes. Some examples are carbohydrates broken down into glucose, proteins broken down into amino acids, and lipids broken down into glycerol and fatty acids.

Stage 2

The second stage is divided into three types, those are-

a) Glycolysis- Under this stage, glucose breaks down into two molecules of pyruvate with two molecules of ATP and NADH. This process takes place in the cytoplasm of the cell, and it does not require any oxygen, i.e., an anaerobic process.

b) Krebs Cycle (Citric Acid Cycle)- Under this stage, the pyruvate produced above, converts into carbon dioxide with a little amount of ATP (Adenosine Triphosphate), and large amounts of NADH and FADH2. This process takes place in the mitochondria of the cell. It carries out in the presence of oxygen only, i.e., the Aerobic process.

c) Electron Transport Chain- The NADH and FADH2 produced in the Krebs Cycle donate their electrons to the electron transport chain, where the chain is a series of proteins. As the electrons pass, energy is released. The energy is used to pump protons across the membrane, creating a proton gradient. And this gradient is used by ATP synthase to produce ATP through oxidative phosphorylation. This stage takes place in the mitochondria and the chain is embedded in the mitochondria.

Stage 3

Oxidative Phosphorylation- Under this stage, the electrons from NADH and FADH2 to oxygen molecules, releasing a large amount of energy. And the energy produced is ATP (Adenosine Triphosphate), through chemiosmosis. And the ATP is used by the cell for carrying out various processes.

Functions of catabolism

Some key functions of Catabolism are-

  1. Energy Production- The primary of all processes conducted through catabolism is the generation of energy. It provides the cell with ATP to support various cellular processes.
  2. Metabolic Homeostasis- Another function of catabolism is to maintain metabolic homeostasis in the body. It maintains the level of glucose, amino acids in the body by breaking and providing storage for later use.
  3. Recycling of cellular components- When the proteins are broken into smaller compounds through catabolism. They can also be used to convert amino acids into new proteins.
  4. Elimination of waste products- It also helps in eliminating waste products from the body. When molecules are broken down to give urea and carbon dioxide, they can excrete from the body.

Difference between Anabolism and Catabolism in points

  • Anabolism is famously known as the constructive part of the metabolic processes, where it builds complex molecules from simple structures and the reaction is enzyme-catalyzed. Whereas, Catabolism is the destructive part of the metabolic process, where it breaks down complex molecules into smaller ones which are also enzyme-catalyzed.
  • In the case of anabolism, it requires energy to conduct the process, so in this case, entropy becomes negative which makes the ∆G positive. This makes the process endergonic. Whereas in the case of Catabolism, it releases energy in the process, so in this case, entropy is positive which makes the ∆G negative. This makes the process exergonic.
  • Catabolism is a process which requires oxygen as all the processes are oxidation reactions, excluding the case of glycolysis. Whereas, anabolism is a process which does not require oxygen to carry out the processes.
  • In anabolism, the hormones involved are estrogen, testosterone, and growth hormones. Whereas, in catabolism hormones involved are adrenaline, cortisol, and glucagon.
  • The primary function of Anabolism is for the growth and maintenance of cells. Whereas, catabolism performs different activities in living systems.


In the end, both processes help humans to sustain life. Without any of the processes, living beings cannot sustain development. As both processes are equally important. It equally distributes the work in a living being and helps it to carry out life processes. If you think of both processes, one makes the complex molecules and the other breaks the complex molecules. It follows a building-breaking mechanism to sustain life on this planet. Therefore, it is very essential to keep this in mind that both processes are equally important and you cannot conclude that one is less important.


  • Catabolism - Wikipedia
  • Anabolism vs Catabolism- Definition, 13 Key Differences, Examples (thebiologynotes.com)
  • Anabolism - Wikipedia
  • Difference Between Anabolism and Catabolism - An Overview (byjus.com)


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"Difference Between Anabolism and Catabolism." Diffzy.com, 2023. Wed. 27 Sep. 2023. <https://www.diffzy.com/article/difference-between-anabolism-and-catabolism>.

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