Metabolism is a biological process that enables an organism to exist, grow, reproduce, heal, and adapt to its surroundings. Metabolism consists of two basic categories of biological reactions: anabolism and catabolism. Anabolism builds complex compounds from simpler ones, whereas catabolism breaks large molecules to smaller ones.
The major difference between anabolism and catabolism is that anabolism builds complex molecules from simpler ones using energy, while catabolism breaks down complex molecules into simpler ones, releasing energy.
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What is Anabolism?
Anabolism, also known as biosynthesis, is the process by which living organisms build complex biological compounds from simpler ones. Anabolism and catabolism are two types of chemical processes in cells that are together referred to as metabolism. Anabolic responses are diverse processes. That is, only a few raw materials are used to produce a large range of end products. This leads to an increase in cellular size, complexity, or both.
Anabolic reactions are endergonic, which means they require an input of energy to proceed and are not spontaneous. Typically, anabolic and catabolic events coexist, with catabolism providing the activation energy for anabolism. The breakdown of adenosine triphosphate (ATP) drives several anabolic activities. Anabolism is primarily driven by condensation and reduction processes.
Stages of Anabolism
Anabolism is divided into three stages. They are:
- Stage 1: Precursor Formation
Precursors for bigger molecules, such as amino acids, monosaccharides, isoprenoids, and nucleotides, are generated.
- Stage 2: Energy Consumption
Energy from ATP is used to convert the precursor from stage 1 into a reactive precursor that can participate in the following metabolic reactions.
- Stage 3: Complex Molecule Formation
This step involves the production of complex big molecules such as proteins, polysaccharides, lipids, and nucleic acid from active precursors.
Functions of anabolism
The catabolic process converts food components into small molecules. Small molecules unite to generate macromolecules throughout the anabolic process. Energy is utilized to build chemical bonds between smaller molecules to form larger molecules. These macromolecules are then employed to create new cells or structures. Anabolism is critical to a cell’s growth, development, and maintenance.
Examples of Anabolism
Cells use anabolic processes to produce polymers, repair tissues, and grow them. For example:
- Disaccharides and water are formed by combining simple sugars
C6H12O6 + C6H12O6 → C12H22O11 + H2O
- Photosynthesis produces glucose and oxygen.
6CO2 + 6H2O → C6H12O6 + 6O2
- Glycerol interacts with fatty acids to form lipids.
CH2OHCH(OH)CH2OH + C17H35COOH → CH2OHCH(OH) CH2OOCC17H35 + H2O
Anabolic Hormones
- Estrogen: Mainly produced in the ovaries, estrogen is present in both males and females. In addition to controlling the menstrual cycle and some female sexual traits like hip and breast growth, it also helps to build bone mass.
- Testosterone: Mainly produced in the testes, testosterone is present in both males and females. It strengthens bones, aids in the development and maintenance of muscle mass, and regulates a few male sexual traits (voice, facial hair).
- Insulin: Made by beta cells in the pancreas, it controls blood glucose levels and utilization. Without insulin, the body is unable to use glucose, which is its primary energy source. Diabetes results from a lack of insulin production by the pancreas or from difficulties the body has processing the insulin it does produce.
- Growth hormone: Growth hormone is a hormone produced in the pituitary that controls and accelerates growth in the first few years of life. Once an adult, it aids in controlling bone healing.
What is Catabolism?
Catabolism refers to the breakdown of complex compounds. Catabolism is the process of breaking down complex compounds into their constituent elements (glucose, amino acids, and fatty acids), which serve as substrates for metabolic pathways.
Catabolism is the metabolic process that converts large, complex molecules into smaller ones in order to produce energy. The destructive branch of metabolism releases energy by breaking down big molecules like as polysaccharides, lipids, nucleic acids, and proteins into smaller units like monosaccharides, fatty acids, nucleotides, and amino acids, respectively.
Stages of Catabolism
Catabolism is a multi-step process that occurs in cells. It is critical to understand where catabolism happens. Mitochondria are the primary organelles responsible for catabolism in the cell. It is a multi-step process. So, let us define the stages of catabolism. There are three major steps of catabolism:
- Stage 1: Digestion stage.
Proteins, lipids, and polysaccharides are examples of complex organic compounds that are catabolized outside of cells into their simpler parts, or monomers. These complex molecules are non absorbent in their complex state; therefore, for absorption, these basic and important molecules must be broken down into easily absorbable and smaller monomers.
- Stage 2: Energy release
Smaller molecules, or monomers, are absorbable and are taken up by cells, where they are reduced to smaller molecules such as acetyl-coenzyme A (acetyl-CoA), releasing energy in the process.
- Stage 3: Energy Stored
In the citric acid cycle and electron transport chain, the CoA’s acetyl group is eventually oxidized to water and carbon dioxide. In this process, the stored energy is released by converting the coenzyme nicotinamide adenine dinucleotide (NAD+) to NADH.
Catabolic Hormones
- Adrenaline: It is also known as epinephrine. The adrenal gland is where this hormone is made. In times of stress or emergency, it causes an increase in heart rate and triggers the “fight-or-flight” reaction.
- Cortisol: The hormone associated with stress. Additionally, the adrenal gland produces it, and when one feels anxious or nervous, they release it. Both blood pressure and blood sugar are raised by it.
- Cytokines: When amino acids are used for various bodily processes, cytokines are released. One type of protein used by cells to communicate is called a cytokine.
- Glucagon: It is the pancreas that produces the hormone glucagon. The breakdown of glycogen into glucose requires this hormone. It is the liver that stores glucagon. Liver is prompted to release glycogen in underactive states or energy-demanding situations, such as combat, exercise, or high levels of stress.
Examples of Catabolism
- The citric acid cycle, glycolysis, lipolysis, oxidative deamination, and oxidative phosphorylation are common catabolic reactions found in all eukaryotic cells.
- The breakdown of nitrogen-containing organic molecules produces ammonia. Some prokaryotes perform nitrification by anaerobically catabolizing ammonia to generate N2. Basically, nitrification converts ammonium to nitrite and nitrate. Nitrosomonas is a soil bacteria. Nitrosomonas, Nitrobacter, and Nitrospira oxidize NH4+ to nitrite (NO2−). During this chemical process, energy is released and used by the bacterium. The bacteria also undertake the reverse process, known as denitrification, which converts nitrate from soil to gaseous molecules such as N2O, NO, and N2.
- The organic compounds of plants and animals are broken down by bacteria and fungi. The microbial breakdown of decomposing matter is one of the main sources of carbon dioxide in the environment.
- The organic compounds of plants and animals are broken down by bacteria and fungi. The microbial breakdown of decomposing matter is one of the main sources of carbon dioxide in the environment.
Difference Between Anabolism and Catabolism
| Categories | Anabolism | Catabolism |
| Definition | Anabolism is the set of metabolic pathways that construct complex molecules from simpler ones. | Catabolism refers to the metabolic pathways that break down large molecules into smaller ones. |
| Role in Metabolism | Anabolism is the building-up phase of metabolism. Anabolism is the constructive phase of metabolism. | Catabolism is the breaking-down phase of metabolism. Catabolism is the destructive phase of metabolism. |
| Energy Requirements | Anabolic processes require ATP energy. | Catabolic processes release ATP energy. |
| Heat | Anabolism involves endergonic reactions, which absorb energy. | Catabolism involves exergonic reactions, which release energy. |
| Hormones | Hormones such as estrogen, testosterone, growth hormone, and insulin play a role in anabolism. | Hormones like adrenaline, cortisol, glucagon, and cytokines are involved in catabolism. |
| Enzymes | Anabolic reactions often involve enzymes like DNA polymerase, RNA polymerase, and various synthases. | Catabolic reactions involve enzymes such as proteases, lipases, and amylases. |
| Oxygen Utilization | Anabolic processes are anaerobic, meaning they do not require oxygen. | Catabolic processes are aerobic, meaning they require oxygen. |
| Effect on the Body | Anabolism contributes to muscle mass increase, tissue formation, repair, and maintenance. | Catabolism leads to the burning of fat and calories and uses stored food for energy production. |
| Metabolic pathways | Common anabolic pathways include the Calvin cycle in photosynthesis and gluconeogenesis. | Common catabolic pathways include glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain. |
| Functionality | Anabolic activities are primarily active during periods of rest or sleep. | Catabolic activities are predominantly active during physical activities. |
| Energy Conversion | In anabolism, kinetic energy is converted into potential energy. | In catabolism, potential energy is converted into kinetic energy. |
| Examples | Examples of anabolic processes include the synthesis of polypeptides from amino acids, glycogen from glucose, and triglycerides from fatty acids. | Examples of catabolic processes include the breakdown of proteins into amino acids, glycogen into glucose, and triglycerides into fatty acids. |
| Processes | Anabolism: This occurs during processes like protein synthesis and photosynthesis. | Catabolism: This occurs during processes such as cellular respiration, digestion, and excretion. |
Video References
References
- https://www.diffen.com/difference/Anabolism_vs_Catabolism
- https://byjus.com/biology/differences-between-catabolism-and-anabolism/
- https://www.toppr.com/guides/biology/differences-between-catabolism-and-anabolism/
- https://www.healthline.com/health/catabolism-vs-anabolism#hormones
- Helmenstine, Anne Marie, Ph.D. “Anabolism and Catabolism Definition and Examples.” ThoughtCo, Aug. 1, 2021, thoughtco.com/anabolism-catabolism-definition-examples-4178390.
- https://byjus.com/chemistry/catabolism/
- https://www.biologyonline.com/dictionary/catabolism
- https://www.geeksforgeeks.org/differences-between-catabolism-and-anabolism/
