Question

Read the given statements and select the correct option. Statement 1: Mitochondria are known as powerhouse of the cell. Statement 2 : ATP synthesis occurs in mitochondria. (a) Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1 . (b) Both statements 1 and 2 are correct but statement 2 is not the correct explanation of statement 1 . (c) Statement 1 is correct and statement 2 is incorrect. (d) Both statements 1 and 2 are incorrect.

Short answer

(a) Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1.

Step-by-step solution

Verify Statement 1

Assess the accuracy of statement 1: 'Mitochondria are known as the powerhouse of the cell.' This statement is a commonly accepted description of the role of mitochondria within the cell. Mitochondria are the organelles where cellular respiration occurs, a process that generates the energy currency of the cell, ATP (adenosine triphosphate). Therefore, the statement is correct.

Verify Statement 2

Assess the accuracy of statement 2: 'ATP synthesis occurs in mitochondria.' The synthesis of ATP takes place in the mitochondria through a process called oxidative phosphorylation, which is part of cellular respiration. Hence, this statement is also correct.

Analyze the Relationship Between Statements

Determine if statement 2 is the correct explanation for statement 1. Since ATP synthesis is the mechanism through which mitochondria provide energy to the cell, and the reason why they are referred to as the powerhouse of the cell, statement 2 is indeed the correct explanation for statement 1.

Key concepts

ATP Synthesis

The process of ATP synthesis is crucial for life, as it provides the energy required for various cellular activities. Within the mighty mitochondria, the energy from nutrients is converted into adenosine triphosphate (ATP), a molecule that acts as the primary energy currency in cells.

This conversion occurs during the final stage of cellular respiration, in a process known as oxidative phosphorylation. ATP synthesis involves a complex enzyme called ATP synthase, which harnesses the energy from a flow of protons across the mitochondrial membrane to synthesize ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi).

Role of ATP synthase

In this process, ATP synthase rotates as protons move through it and this rotation facilitates the addition of a phosphate group to ADP, forming ATP. It's a beautiful molecular dance that powers nearly every cellular function - from muscle contraction to nerve impulse transmission.

Cellular Respiration

Cellular respiration is the life-sustaining process by which cells break down glucose and other food molecules in the presence of oxygen to produce energy. It occurs in a series of metabolic pathways, with three primary stages: glycolysis, the citric acid cycle, and oxidative phosphorylation.

During glycolysis, glucose is split into two molecules of pyruvate, generating a small amount of ATP and electron carriers. In the citric acid cycle, pyruvate is further broken down, and more electron carriers are produced. These electron carriers then donate electrons to the electron transport chain in the mitochondrial membrane during oxidative phosphorylation.

Importance for Energy Production

It is through cellular respiration that cells manage to extract a large amount of energy stored in food and convert it into a form that can be used for cellular processes, making it indispensable for cell survival and function.

Oxidative Phosphorylation

Oxidative phosphorylation is where the magic happens in the production of ATP. It's the final and most yield-efficient stage of cellular respiration taking place in the inner mitochondrial membrane. This stage comprises an electron transport chain and a process known as chemiosmosis.

Electrons from the carriers NADH and FADH2 are transferred through a series of protein complexes, which pump protons into the intermembrane space, generating a proton gradient. The flow of protons back into the mitochondrial matrix, driven by this gradient, is what powers ATP synthase to phosphorylate ADP into ATP.

Proton Gradient and ATP Yield

The incredible efficiency of this system means that a sizable amount of ATP can be generated — around 34 ATP molecules from a single molecule of glucose. Importantly, this ATP production is dependent on a continuous supply of oxygen, making oxidative phosphorylation an aerobic process.