ATP - structure and role of ATP

All human beings consist of living cells.

Cells need energy to drive many processes.

Cells need energy for processes such as muscle contraction, nerve impulse propagation, and chemical synthesis.

ATP provides energy to drive many processes in living cells.

ATP is found in all forms of life. It is referred to as the "molecular unit of currency" of intracellular energy transfer.

When consumed in metabolic processes, it is converted either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP).

Each day, the human body probably uses ATP equivalent to its own body weight.

Let’s discuss the structure of ATP.

ATP is an organic compound with a complex structure.

Adenosine triphosphate (ATP) consists of a nitrogenous base (adenine), a pentose sugar (ribose), and three phosphate groups.

The last two phosphate groups are joined with the adenosine monophosphate by high energy bonds.

Bond is represented by the symbol (~). A phosphate group has one atom of phosphorus and four atoms of oxygen.

The third and the second bonds of ATP release energy of about 8.9 kcal (37.25 kJ) or more on hydrolysis.

Let's study its role as an excellent energy carrier.

The energy released by high energy bonds is utilized for driving energy-dependent reactions in the cells.

ATP is a biologically useful ‘energy- carrier’. It is the most common energy- carrier in cells and is often called the ‘energy currency’ of the cell.

ATP was discovered as the key source of energy in all living things by a German biochemist Lohmann in 1929.

ATP provides energy for muscle contraction, nerve impulse propagation etc.

Lohmann identified that ATP occurs in all cells and provides energy for all the biochemical reactions occurring inside the cell.

Each cell generates its own ATP and ATP molecules do not move from one cell to another.

Fritz Lipmann established that ATP acts as an energy shuttle.

It is an energy shuttle that collects energy from catabolic reactions and transfers it to anabolic reactions that need energy.

Thus, energy released during exergonic reactions combines with ADP to form ATP (i.e., ADP + Phosphate + Energy = ATP).

An exergonic reaction is a chemical reaction where the change in the free energy is negative and there is a net release of free energy.

In endergonic reactions, ATP releases energy and changes to ADP (i.e., ATP = ADP + Pi + Energy).

An endergonic reaction is a chemical reaction in which the standard change in free energy is positive, and energy is absorbed.

The difference between ATP and ADP is found in the number of phosphate groups. ATP has three phosphate groups and ADP has two.

Revision

ATP is an organic compound that provides energy to drive many processes in living cells.

When consumed in metabolic processes, it is converted to adenosine diphosphate (ADP) or adenosine monophosphate (AMP).

ATP consists of adenine, ribose and three phosphate groups.

ATP is known as a biologically useful “energy- carrier”. ATP molecules do not move from one cell to another.

Lohmann discovered ATP in 1929. He identified that ATP provides energy to all the biochemical reactions in the cell.

Fritz Lipmann found that ATP acts as an energy shuttle.

ATP has three phosphate groups but ADP has only two.

The end