Question

Assertion: ATP acts as energy currency of cell. Reason: ATP broken down whenever and wherever energy needs to be utilized.

Short answer

Yes, the assertion and reason are correct. ATP does act as the energy currency of the cell because it stores energy needed for various cell activities. The energy is released when ATP is broken down, making it available for use wherever and whenever needed in the cell.

Step-by-step solution

Understand ATP

Adenosine Triphosphate (ATP) is a complex organic chemical that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, chemical synthesis, and ion transport. It is often called the 'energy currency of life.'

How ATP works as energy currency

ATP works as energy currency because it has the capacity to store energy in its bonds. In a cell, when a process requires energy (for example, to drive a biochemical reaction), ATP is broken down, releasing energy and leaving behind a molecule of ADP (adenosine diphosphate) and inorganic phosphate. This is known as ATP hydrolysis.

Why ATP is broken down

ATP is broken down whenever and wherever energy needs to be utilized because that's how the energy stored in its bonds is made available to do work. So, ATP acts as a go-between molecule that couples energy-yielding reactions with energy-requiring reactions in the cell.

Key concepts

Adenosine Triphosphate (ATP)

Imagine you are a city with various structures requiring power to function – this is similar to your cells that need energy to perform countless activities. ATP, or Adenosine Triphosphate, is like the electricity grid of the cell, providing essential energy wherever and whenever it's needed.

ATP consists of adenine, ribose (a sugar), and three phosphate groups. The bonds holding these phosphates carry potential energy. This energy is harnessed to fuel various cellular tasks such as building proteins, duplicating DNA, and transporting molecules against a gradient. Think of ATP as a rechargeable battery that gets 'charged up' during food breakdown and 'spent' performing cellular duties.

ATP hydrolysis

When the cell requires energy, ATP undergoes a reaction known as hydrolysis. This process involves the cleavage of the last phosphate group, resulting in ADP (Adenosine Diphosphate), a free phosphate group, and the release of energy.

During ATP hydrolysis, the enzyme ATPase facilitates the breaking of the bond in a controlled manner so that the energy released can be used productively. To visualize this, imagine a controlled demolition of a building where the energy is directed to accomplish a specific task. The energy from ATP hydrolysis drives cellular operations that are essential for life, ranging from muscle contractions in humans to the opening of stomata in plants.

Biochemical energy storage

Like a warehouse stores goods, cells store energy, ensuring a continuous supply is available to meet their demands. The main 'storage unit' is ATP. Cells stockpile energy in the form of ATP during energy-abundant times - like during or after a meal. Then, they tap into this reserve during energy scarcity. This is akin to saving money in a bank to use it later.

Other molecules also participate in biochemical energy storage, such as NADH and FADH2, which serve in the electron transport chain to ultimately generate ATP. The body's ability to store and access energy efficiently is crucial for survival, allowing organisms to function effectively even when external energy sources are scarce.

Cellular energy processes

ATP is central to numerous cellular energy processes, comprising a vast network of metabolic pathways that are interconnected. Just as various pathways in a city keep traffic flowing, metabolic pathways efficiently channel energy throughout the cell. These pathways include glycolysis, the citric acid cycle (also known as the Krebs cycle), and oxidative phosphorylation.

Each pathway has unique steps involving specific enzymes and substrates, and they all contribute to the ultimate goal of ATP production. ATP generated from these metabolic reactions powers the cell's daily operations - from dividing cells, to beating hearts, to thinking brains. Understanding these processes is fundamental to comprehending how life is powered on the most basic cellular level.