Question

Assertion: \(\mathrm{F}\) particles are present in the inner mitochondrial membrane. Reason: The passage of protons through the channel is coupled to the catalytic site of the \(\mathrm{F}_{1}\) component for the production of ATP.

Short answer

Both the assertion and reason are correct, and the reason correctly explains the assertion.

Step-by-step solution

Understanding the Assertion

Firstly, let's assess the Assertion: '\(\mathrm{F}\) particles are present in the inner mitochondrial membrane'. The \(\mathrm{F}\) particle, better known as complex \(\mathrm{F}_{1}\mathrm{F}_{0}\) ATP synthase, is indeed located in the inner mitochondrial membrane. So, this assertion is true.

Understanding the Reason

Secondly, let's analyze the Reason: 'The passage of protons through the channel is coupled to the catalytic site of the \(\mathrm{F}_{1}\) component for the production of ATP'. The \(\mathrm{F}_{1}\mathrm{F}_{0}\) ATP synthase has an \(\mathrm{F}_{1}\) component that acts as a catalytic site for ATP production. This process is driven by the flow of protons (H+) across the membrane which indeed couples with the \(\mathrm{F}_{1}\) component to produce ATP. Therefore, the reason is also true.

Correlation Between Assertion and Reason

Now, it's crucial to determine if the assertion and reason are directly related. The assertion states where the \(\mathrm{F}\) particles or \(\mathrm{F}_{1}\mathrm{F}_{0}\) ATP synthase are located, and the reason explains their function, i.e., the production of ATP through proton movement. So, not only both the statements are true, but the reason correctly explains the assertion.

Key concepts

F1F0 ATP Synthase

One of the most crucial components of cellular energy production is the F1F0 ATP synthase. This enzyme is a marvel of biological engineering and is primarily responsible for the synthesis of ATP (adenosine triphosphate), which is the energy currency of the cell. Located within the inner mitochondrial membrane, the F1F0 ATP synthase operates somewhat like a molecular turbine.

It consists of two main parts: the F0 unit, which is embedded in the membrane and acts as a channel for protons, and the F1 unit, which protrudes into the mitochondrial matrix and houses the catalytic sites for ATP synthesis. Protons flow through the F0 unit due to a proton gradient, and this flow drives the rotation of the F1 unit. This rotational motion allows the enzyme to convert ADP (adenosine diphosphate) and inorganic phosphate into ATP during a process known as oxidative phosphorylation.

Understanding how these two components of the synthase work together is fundamental. The F0 unit uses the energy stored in the proton gradient across the inner mitochondrial membrane, which is established by the electron transport chain during cellular respiration, to power ATP synthesis. In essence, the F1 unit captures and converts this energy into a form that can be used by the cell for various metabolic processes.

Inner Mitochondrial Membrane

The inner mitochondrial membrane plays a pivotal role in cellular respiration and energy production. It is the site where vital components like the F1F0 ATP synthase reside. What's special about this membrane is its impermeability to most ions and molecules, creating a highly controlled environment for the generation of energy.

This selective barrier allows the establishment of an electrochemical gradient, also known as the proton motive force. This gradient is created by the electron transport chain that pumps protons (H+) from the mitochondrial matrix to the intermembrane space, leading to a higher concentration of protons outside than inside the matrix.

The impermeability of the membrane ensures that protons cannot simply diffuse back into the matrix, but must pass through specific channels like those provided by the F1F0 ATP synthase. This tightly regulated flow of protons is what ultimately drives ATP synthesis.

Moreover, the inner mitochondrial membrane contains other proteins such as transporters and carriers that aid in substrate movement and the regulation of mitochondrial function. It's a hub of coordinated activity, vital for the cell's life and death.

Proton Gradient and ATP Production

The connection between a proton gradient and ATP production is a testimony to nature's efficiency at converting energy. Inside mitochondria, ATP production is closely tied to the maintenance of a proton gradient across the inner mitochondrial membrane during cellular respiration.

Through a series of redox reactions, high-energy electrons are transferred within the electron transport chain, and the energy released from these transfers is used to pump protons into the intermembrane space. This creates a high proton concentration outside the matrix, setting up the proton gradient or electrochemical gradient. The desire of protons to move back into the matrix, where their concentration is lower, provides the driving force for ATP production. This process is known as chemiosmosis.

When protons flow back into the mitochondrial matrix through the F1F0 ATP synthase, their kinetic energy is harnessed to produce ATP from ADP and inorganic phosphate. This transformation from a gradient to a chemical energy form is elegant and crucial for cellular metabolism. It's important to understand that the integrity of the inner mitochondrial membrane and the proper function of the ATP synthase are critical for this process to occur efficiently. Any disruption in these components can impair cellular energy production and ultimately impact cell function.