Metabolism

What is metabolism in the body?

Metabolism is the process of breaking nutrients into fundamental components and then building it up in several useful ways. It can be useful for structure, useful for providing energy so that it is easier for us to sustain our lives with all processes such as reproduction, growth and response to surroundings. 

Metabolism Meaning

Metabolism Definition- It can be defined as all the chemical reactions taking place inside of a cell often linked in pathways or chains. 


In some of the chemical reactions taking place during metabolism, energy is released and in others, energy is added for the reactions to take place. A metabolism example of the former case is cellular respiration where a sugar molecule is broken down and energy is released in the form of ATP (Adenosine Triphosphate); an example of the latter is photosynthesis where sunlight energy is used by plants to convert carbon dioxide into sugar molecules.

Types of Metabolism

Metabolism consists of two different processes:

  1. Catabolism: Breaking down the substances for energy or structure to getting back to the building blocks.

  2. Anabolism: Rebuild the substances in ways that we find it useful.

Catabolic and Anabolic Pathways

A metabolic pathway is a series of linked chemical reactions that include making and breaking down glucose molecules and releasing or utilising energy. The building up pathway is Anabolic pathway whereas breaking down pathways is a catabolic pathway. Let’s discuss these two pathways in detail:

Anabolic Pathway

It helps in building complex molecules from simpler molecules and here energy is consumed i.e. it needs the input of energy. A few examples of the anabolic pathway include-


  • Synthesis of proteins from amino acids 

  • DNA strands from nucleic acid building blocks called nucleotides.

  • Conversion of amino acids into keratin

  • Conversion of glycogen or starch from the glucose molecule

  • The energy used in these important biosynthetic processes is in the form of ATP and other short-term energy storage molecules. 

Catabolic Pathway

It involves the breakdown of complex molecules into simpler ones and is a pathway that releases energy in the form of ATP. Metabolism examples for the catabolic pathway include-


  • The breakdown of glucose into Pyruvate

  • Conversion of proteins into amino acids

  • Conversion of lipids or fats into fatty acids

  • All of these degradations occur in a pathway and energy (ATP) is released to power the work of cells.


When we eat food, the molecules are converted to amino acids, sugars and fatty acids with the release of ATP (energy) and waste materials like Nitrogen, CO2, Phosphorus and Sulphur excreted out of the body. Here, we can see whatever we put inside our body in the form of food, it changed into another form.  


The outcomes of the catabolic pathway are absorbed by our intestines, enter the bloodstream and then are distributed to the body cells. Its functions include-


The energized cell forms replacement parts for its own molecules which are worn out and other times, it builds energy molecules in the body.

These act like fuel to power the cell’s future activities. Example- Muscle cells use energy molecules to contract and brain cells utilize them to form thought processes.

FAQ (Frequently Asked Questions)

1. What is metabolism in human body and what is the importance of metabolism?

Metabolism is the set of biochemical reactions in organisms that are required to sustain life. The major three functions of metabolism include

  • Convert food to energy which is required to run cellular processes

  • Convert food or fuel to building blocks of the body including proteins, lipids, nucleic acids, carbohydrates. 

  • It is also responsible for the elimination of nitrogenous wastes.

  • All of the biochemical reactions are catalyzed by enzymes.

  • It allows organisms to grow and reproduce, maintain structures and respond to their respective environment.

2. What are the two pathways involved in metabolism?

The catabolic pathway and the anabolic pathways are the two pathways that take place in metabolism. The catabolic pathway is meant to break complex substances into a simpler form with the release of energy in the form of ATP and the anabolic pathway is meant to build larger molecules from smaller molecules and they consume energy for this process.

3. What is ATP?

ATP stands for Adenosine triphosphate. It is an organic compound and it provides energy to drive many processes in a living cell. It is often referred to as the molecular unit of currency that captures chemical energy received from the breakdown of food molecules and then releases it to give power to the other cellular processes. It is very important for all the metabolic reactions taking place in the body. In biochemistry terms, ATP is a nucleoside triphosphate, indicating that it consists of three components: a nitrogenous base (adenine), the sugar (ribose) and the triphosphate.

4. Is a high metabolism good? How to increase metabolism in the body?

There is a great importance of metabolism in the human body. High metabolism is good if you want to burn more calories and get in shape as it helps you burn calories even at rest including during activities. Maintaining body weight is easier for people having higher metabolic rates and people sometimes struggle to lose weight as metabolism is hindered in their body due to various factors such as losing muscle mass and gaining more body fat. Therefore, one can increase metabolism if they eat a balanced diet containing lots of protein making it 20-30 percent of their food intake. Also, high intensity workouts, getting a calm night’s sleep and using various spices in diet like turmeric, cinnamon, fennel seeds, cardamom, rosemary, cumin and ginger will help increase metabolism in the human body.

5. What foods slow down your metabolism?

Most of the junk foods are associated with slowing down the metabolism as these contain unhealthy fats. White flour, soda and soft drinks with high fructose quantity, beef, etc. are used in such foods which are not considered good for a healthy body.