Question

What type of reaction releases the energy of an ATP molecule? Explain. (page 39 )

Short answer

The type of reaction that releases the energy of an ATP molecule is hydrolysis. During hydrolysis, ATP reacts with a water molecule, and one of its phosphate groups is removed, resulting in the formation of ADP (adenosine diphosphate) and an inorganic phosphate (Pi). The energy is released upon breaking the high-energy phosphate bond, which is a highly exergonic reaction. This energy release is crucial for various cellular processes and maintaining the energy balance of the cell.

Step-by-step solution

Identify the ATP molecule

Adenosine triphosphate (ATP) is a nucleotide that serves as the main energy currency for cells. It is composed of an adenine base, a ribose sugar, and three phosphate groups. The energy released from ATP comes from the breakdown of the phosphate bonds.

Type of reaction that releases energy from ATP

The type of reaction that releases the energy of an ATP molecule is called hydrolysis. Hydrolysis is a chemical reaction in which a molecule is split into two parts by reacting with a water molecule. In the case of ATP, when it undergoes hydrolysis, one of its phosphate groups is removed, resulting in the formation of ADP (adenosine diphosphate) and an inorganic phosphate (Pi). \[ ATP + H_2O \rightarrow ADP + P_i \]

Explain the energy release in ATP hydrolysis

The ATP hydrolysis releases energy because breaking the high-energy phosphate bond is a highly exergonic reaction, which means it releases more energy than it requires to occur. The released energy is used to perform various cellular activities such as muscle contractions, transport of molecules across membranes, and synthesis of other molecules. Additionally, the hydrolysis of ATP is a reversible reaction, so when the cell has excess energy, the ADP and Pi can be recombined to form ATP, effectively storing the energy for later use.

Importance of the ATP hydrolysis in cellular processes

ATP hydrolysis serves as a source of energy for many cellular processes, including metabolism, maintaining ion gradients across membranes, and cellular signaling. By coupling ATP hydrolysis with energy-requiring processes, cells can effectively harness the energy released during ATP hydrolysis to drive reactions that are not favorable on their own. In conclusion, ATP hydrolysis is the type of reaction that releases the energy of an ATP molecule. The energy is released upon the breakdown of a high-energy phosphate bond in ATP, forming ADP and an inorganic phosphate. This energy release is crucial for various cellular processes and maintaining the energy balance of the cell.

Key concepts

Adenosine Triphosphate (ATP)

Imagine ATP as the power coin of the cell, like money is for buying goods; cells spend ATP to carry on their daily functions. Adenosine triphosphate, or ATP, is the primary molecule that stores and transfers energy in cells. Its structure consists of an adenine base attached to a ribose sugar, which is in turn linked to a chain of three phosphate groups. The secret of ATP's energy lies in the bonds between these phosphates; especially the last two are known as high-energy phosphate bonds.

Cells use the energy from ATP to perform nearly every task, from muscle contractions to sending signals between nerve cells. The energy of ATP is not stored as a battery, but rather, it's a disposable form of energy currency that's constantly being used and regenerated within the cell.

Chemical Reactions in Biology

The stage of life's processes is set on a cellular level, where myriad chemical reactions take place. These are precisely choreographed sequences where molecules interact and change, leading to life's complexity. Biological chemical reactions can be as simple as ions passing through a protein channel, or they can be as intricate as the synthesis of large biomolecules.

One of these critical reactions is ATP hydrolysis, a reaction where ATP reacts with water, causing a phosphate group to break away and release energy. This is just one example of how chemical reactions are meticulously used in biology to manage and control the flow of energy necessary for life to thrive.

Cellular Energy Transfer

The energy in a cell isn't raw or unmanaged; it's careful transferred and directed where needed by precise mechanisms. ATP serves as the main intermediary in this energy transfer. When a cell requires energy, ATP is broken down through the process of hydrolysis, described previously. This reaction is pivotal because it provides a controlled way of releasing and directing energy.

The cell's ability to harness the energy from ATP hydrolysis allows it to actively transport substances, complete mechanical work, and drive endergonic reactions, which require an input of energy. Thus, ATP is not just a source of energy, but also a method of energy redistribution within the cell.

Exergonic Reactions

Exergonic reactions are the type of chemical reactions that release energy during the process of the reaction, usually in the form of heat or light. ATP hydrolysis is a prime example of an exergonic reaction, releasing energy that the cell can then harness. The 'exergonic' nature means that these reactions can occur spontaneously because the energy of the products is less than the energy of the reactants.

In contrast to endergonic reactions, which require an input of energy, exergonic reactions, such as ATP hydrolysis, are crucial for life because they provide the energy necessary for many biological processes. Understanding how these reactions work, and how they interact with other cellular processes, is key to comprehending how life obtains and uses energy to function.