Energy Currency of the Cell

What is Energy?

All the biotic components inclusive of plants, animals, birds, human beings, and insects need the energy to sustain proper maintenance and functioning of the body. The green plants use sunlight to obtain energy while animals feed upon the plants to get energy. Some animals feed on other animals. Energy is the fuel for the body. Human beings obtain energy from what they eat. In this article, we will learn about how energy is produced and stored in the body.


What is ATP-Adenosine Triphosphate?

The energy currency of the cell is known as ATP or Adenosine Triphosphate. ATP is an organic compound which consists of various phosphate groups, adenine and ribose sugar. These molecules are responsible for generating energy for the various biochemical processes in the body. ATP molecules are present in all cells of living organisms. They obtain the chemical energy from digested food and release the energy to run various chemical processes in the body. The ATP molecules are synthesized inside the mitochondria which are commonly called the powerhouse of the cell.


The German chemist Karl Lohmann was the first one to discover the ATP molecule. In the year 1948, Scottish Biochemist Alexander Todd synthesized the first ATP molecule biochemically.


Structure of ATP Molecule

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Adenosine triphosphate molecule is a nucleotide with adenine and three phosphate groups present in it. It is soluble in water and has a high energy content. This is because of the two phospho-anhydride bonds which are linked to the three phosphate groups.


ATP Molecule

ATP – Adenosine triphosphate is a nucleotide, which is mainly composed of the molecule adenosine and three phosphate groups. It is soluble in water and has a high energy content, which is primarily due to the presence of two phospho-anhydride bonds connected to the three phosphate groups.


The actual power source of the ATP is the triphosphate tail which is tapped by the cell. The energy available is contained in between phosphates and it is released as molecules split. This is facilitated by hydrolysis. In this process, the ATP gets converted to ADP which is adenosine diphosphate, a nucleotide with just two phosphate groups.


ATP Biology

ATP molecules are principally composed of three important constituents.

  • The pentose sugar molecule i.e. ribose sugar.

  • Nitrogen base- Adenine, linked to the first carbon of this sugar molecule.

  • The three phosphate groups are attached in a chain to the 5th carbon of the pentose sugar. The phosphoryl groups, starting with the group closest to the ribose sugar, are referred to as the alpha, beta, and gamma phosphates. These phosphates play an imperative role in the activity of ATP.


ATP Energy 

In the ATP molecule the three phosphate groups present form a very high energy bond which leads to the liberation of huge amounts of energy on splitting. Life cannot exist without the energy that is obtained from the ATP. It is used by various enzymes and structural proteins in cellular processes like biosynthetic reactions, cell divisions, etc. This “energy currency of the cell” is produced during cellular respiration where a digested simple molecule of food is utilized. Once after the energy is produced by the ATP molecules, they are stored in its bonds which are later utilized by the cells by breaking the bonds whenever required

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Functions of ATP

  • ATP is used to carry out various cellular functions in the body, for example, transportation of different molecules across the cells.

  • ATP also aids in supplying energy for efficient transport of blood and other nutrients.

  • ATP helps in muscle contraction.

  • ATP aids in locomotion and other movements of the body.

  • ATP helps in synthesizing many types of macromolecules required by the cell for survival.

  • ATP molecules are used to regulate chemical reactions and neuron transmissions.

FAQ (Frequently Asked Questions)

What is the Role of ATP?

  1. The ATP molecules can be reprocessed after every reaction.

  2. ATP molecule provides energy for both the exergonic and endergonic processes.

  3. ATP serves as an extracellular signaling molecule.

  4. it acts as a neurotransmitter in both central and peripheral nervous systems.

  5. It is the only energy, which can be directly used for different metabolic processes. Other forms of chemical energy need to be converted into ATP before they can be used.

  6. It plays an important role in Metabolism – A life-sustaining chemical reaction including cellular division, fermentation, photosynthesis, photophosphorylation, aerobic respiration, protein synthesis, exocytosis, endocytosis, and motility.

What is the Significance of ATP?

  1. ATP plays a critical role in the transport of macromolecules such as proteins and lipids into and out of the cell.

  2. ATP has recently been proposed to act as a biological hydrotrope and has been shown to affect proteome-wide solubility.

  3. ATP is involved in signal transduction by helping as a substrate for kinases, enzymes that transfer phosphate groups. 

  4. ATP is one of four "monomers" required in the synthesis of RNA. The process is promoted by RNA polymerases

  5. Transporting chemicals out of a cell against a gradient is often associated with ATP hydrolysis. 

  6. Cells secrete ATP to communicate with other cells in a process called purinergic signaling. ATP serves as a neurotransmitter in many parts of the nervous system, modulates ciliary beating, affects vascular oxygen supply, etc.