Problem 23 - Objective Biology for NEET

Question

Which one of the following aspects is an exclusive characteristic of living things? (a) Isolated metabolic reactions occur in vitro. (b) Increase in mass from inside only. (c) Perception of events happening in the environment and their memory. (d) Increase in mass by accumulation of material both on surface as well as internally.

Step-by-Step Solution

Answer

The exclusive characteristic of living things from the provided options is (c) Perception of events happening in the environment and their memory.

Step 1: Evaluate First Statement

The first statement (a) 'Isolated metabolic reactions occur in vitro.' talks about the metabolic reactions which can happen in living things or outside of a living organism, in a test tube for example (in vitro). However, this is not an exclusive characteristic of living organisms, since it can occur outside of them as well, hence this option is incorrect.

Step 2: Evaluate Second Statement

The second statement (b) 'Increase in mass from inside only.' refers to growth, but it is not exclusive to living things, as crystals for example also grow from within, hence this option is incorrect.

Step 3: Evaluate Third Statement

The third statement (c) 'Perception of events happening in the environment and their memory.' This refers to awareness and memory, which is exclusive to living beings, hence this is the correct option.

Step 4: Evaluate Fourth Statement

As for the fourth statement (d) 'Increase in mass by accumulation of material both on surface as well as internally.' This also refers to a form of physical growth, which is not exclusive to living entities, as non-living things like mountains can increase in mass both internally and on their surface. Hence, this option is incorrect.

Key Concepts

Metabolic Reactions In Vitro

Exploring the fascinating world of metabolic reactions offers us a glimpse into how living organisms convert food into energy. It's intriguing to know that we can replicate certain metabolic processes outside the complex environment of a living cell – this is what we call 'in vitro' (in the glass) metabolic reactions. They are carried out in controlled laboratory environments, such as in test tubes or petri dishes, using enzymes and other biological molecules extracted from living organisms.

These reactions are conducted for various research and industry applications, including drug development and the study of disease pathways. Despite being a profound tool to understand life's chemistry, the ability to carry out 'in vitro' metabolic reactions isn't an exclusive property of living beings. In fact, it is a replication and study of their biochemical processes in an artificial setup. To improve upon this concept, it is essential to understand that while 'in vitro' experiments mimic life, they do not equate to the dynamic metabolic activities happening within the intricacies of an actual living cell.

Growth in Living Organisms

When we think of growth, we often think of getting taller or bigger, and it's something we've all experienced. Growth in living organisms is inherently different from physical changes observed in non-living matter. Living beings grow from the inside, with cells multiplying and increasing in size, which is underlined by a complex genetic control. This internal growth is a coordinated process involving various biological factors like hormones, nutrients, and the organism's health status.

To clarify further, it's important to understand that while living organisms grow from within, some non-living things can appear to grow, such as crystals. However, their growth lacks the biological governance and functionality inherent to living organisms. Recognizing this distinction helps us to appreciate the complex nature of life that goes beyond mere increase in mass.

Perception and Memory in Living Beings

Imagine you touch a hot surface and immediately retract your hand. That instant reaction is a part of what sets living organisms apart - the ability to perceive their environment and react accordingly, which is linked to memory. This perceptive ability isn't about simply responding to stimuli, but it involves a conscious recognition which non-living entities do not exhibit.

In the realm of living beings, perceptive mechanisms range from simple to complex. From single-celled organisms that react to chemical signals, to humans and other animals that can remember, learn, and even plan based on past experiences. Memory is not just a recollection of past events; it's a sophisticated process involving the storage, retrieval, and modification of information that directly influences behavior. This process, exclusive to living things, encapsulates their dynamic interaction with the environment and is foundational to survival and adaptation.