Problem 148 - Objective Biology for NEET

Question

Assertion: Living state is a non-equilibrium steady state to be able to perform work. Reason: System at equilibrium cannot perform work.

Step-by-Step Solution

Answer

True. The assertion and reason are both correct, and the reason correctly explains the assertion. A living state can perform work because it is a non-equilibrium steady state that engages with its environment and experiences energy flow, while a system at equilibrium can't perform work because it is isolated, experiences no change, and is at the minimum of its free energy.

Step 1: Understanding the Living State

The living state of an organism is a non-equilibrium steady state, meaning it is a state that, although stable, is not in equilibrium. This is because living organisms are continually interacting with their environment, taking in energy and matter, and releasing them again.

Step 2: Understanding Equilibrium

Equilibrium in thermodynamics is a state in which there is no flow of matter or energy, and there is no change in the system over time. A system in equilibrium, therefore, is at the minimum of its free energy.

Step 3: Defining Work

In the context of thermodynamics, work is defined as a force that changes the state of a system (either by moving something against a resistive force or changing pressure, temperature, etc).

Step 4: Reason Living State Can Perform Work

Living organisms, being in a non-equilibrium steady state, can perform work as they are capable of taking in energy and matter from their environment, converting them into useful forms, and continuously undergoing changes. Energy flow is necessary for them to perform activities and maintain their living state.

Step 5: Reason System at Equilibrium Cannot Perform Work

A system at equilibrium, on the other hand, cannot perform work. This is because it is at the minimum of its free energy and there are no exchanges of matter or energy because the system is isolated. Since work is a force that results in a change to the system, and there are no changes in an equilibrium state, no work can be done.

Key Concepts

Non-Equilibrium Steady State

The notion of a non-equilibrium steady state is intrinsic to understanding how living organisms operate. This concept indicates that while an organism may appear to remain constant over time, it is actually in a state of continuous intake and release of energy and matter.

In comparison to non-living systems, which may reach a state of thermodynamic equilibrium, living systems actively avoid equilibrium in order to function. Despite the constant flux, their internal processes are regulated, maintaining a stable condition necessary for life's complexity.

For instance, a cell in our body is in a continuous state of taking in nutrients, converting them into energy through metabolic processes, and expelling waste. This state of flux is indispensable as it allows for adaptation to changes in the environment, growth, and reproduction. Therefore, the living state is a delicate, yet dynamic balance, fueled by ceaseless energy conversions.

Thermodynamic Equilibrium

In contrast to the bustling energy of living systems, thermodynamic equilibrium refers to a state of balance where a system has no net exchange of energy or matter with its surroundings. At this point, the system's properties, like temperature and pressure, become uniform, indicating that all internal movements or reactions have stopped.

From a biological perspective, an organism at thermodynamic equilibrium is no more capable of sustaining life. This kind of equilibrium implies that there is no longer any potential for doing work, as the system's free energy—the energy available to perform work—is at its lowest. This principle is a foundation of thermodynamics, underlined by the fact that work is needed for change, and without change, organisms cannot maintain the processes essential for life.

This concept is key for understanding why death results in a body cooling down and reaching room temperature, essentially achieving thermal equilibrium with its surroundings, unlike the active and warm state of living organisms.

Energy Flow in Organisms

The flow of energy in organisms is at the very heart of sustaining life. Energy is required for a myriad of processes, from the microscopic to the macroscopic. Every task performed, from synthesizing proteins within a cell to running a marathon, involves the transformation of energy from one form to another.

The primary source of this energy for many organisms is the sun, absorbed by plants through photosynthesis, which then forms the base of the food chain. Animals consume plants (or other animals) to acquire this energy, using it to maintain their non-equilibrium steady state by performing functions that include movement, growth, and homeostasis.

In essence, energy flow in organisms is a complex network involving numerous biochemical pathways. This energy is ultimately released back into the environment, primarily as heat—a testament to the fundamental law of conservation of energy that states energy is neither created nor destroyed, only transformed.