Problem 56 - Objective Biology for NEET

Question

Which of the following are not essential elements for growth? (a) Water (b) Oxygen (c) Both (a) and (b) (d) None of these

Step-by-Step Solution

Answer

(d) None of these

Step 1: Identify the role of water in growth

Water is a fundamental element needed for growth in nearly all organisms. It is involved in many mechanisms such as carrying nutrients to cells, expelling waste, and aiding in chemical reactions. Therefore, it is deemed essential for growth.

Step 2: Identify the role of oxygen in growth

Oxygen is utilized for cellular respiration in many organisms, especially animals. Without oxygen, cells would not be able to extract energy from food. Therefore, oxygen is also deemed essential for growth.

Step 3: Analyse the Options

Given the roles of water and oxygen in supporting the growth process as discussed in the previous steps, it can be deduced that both are essential elements for growth. Thus, the correct answer is (d) None of these, since neither water nor oxygen can be categorized as non-essential for growth.

Key Concepts

Role of Water in Growth

Water is crucial for the growth of all living organisms. It acts as a medium for transporting nutrients and minerals within the organism. Imagine a highway system where all essential nutrients travel to reach each cell. Water also helps in maintaining cell structure by exerting pressure against cell walls.
Every single cell is primarily composed of water, and this hydration is necessary for maintaining cellular function and structural integrity. Moreover, water facilitates crucial chemical reactions within cells, playing a vital role as a solvent. These activities help sustain life and promote growth.

Role of Oxygen in Growth

Oxygen plays a pivotal role in the growth of aerobic organisms. It is essential for cellular respiration, a process where cells produce energy from nutrients. Think of it as a power plant generating electricity for city use. During cellular respiration, oxygen helps break down glucose molecules, releasing energy in the form of ATP (Adenosine Triphosphate), which fuels cellular activities.
Without oxygen, many organisms would struggle to obtain the energy required for growth and repair. Interestingly, some organisms like plants also produce oxygen through photosynthesis, which is then used for respiration or released into the atmosphere. This oxygen cycle is essential for sustaining life on Earth.

Cellular Respiration

Cellular respiration is the process through which cells convert nutrients into energy. This is accomplished with oxygen and takes place in several stages. These stages include glycolysis, the Krebs cycle, and the electron transport chain.
During glycolysis, glucose is broken down into smaller molecules, yielding a small amount of ATP. This stage occurs in the cytoplasm. In the Krebs cycle, which happens in the mitochondria, further breakdown of these molecules takes place, yielding more ATP and releasing electrons. Finally, the electron transport chain uses these electrons to produce a large amount of ATP, concluding the energy extraction process.

• Energy production: Cellular respiration is critical for energy generation.
• Component molecules: ATP is the main energy currency of the cell.

Nutrient Transport

Nutrient transport is the movement of essential nutrients from one part of the organism to another. In plants, water acts as a conduit facilitating this movement, often involving xylem and phloem tissues. In animals, the circulatory system performs this function, distributing nutrients to different parts.
Essential minerals and nutrients like nitrogen, phosphorus, and potassium, are dissolved in water and carried to cells, which use them for various metabolic activities. This transport process is vital for the distribution of resources, ensuring cells receive what they need to function and grow. Additionally, the removal of waste products through similar pathways prevents cellular damage and maintains homeostasis.

Biological Chemical Reactions

Biological chemical reactions are integral processes that occur within organisms to maintain life. They involve the conversion of molecules through various pathways, which are often catalyzed by enzymes. For example, photosynthesis and cellular respiration are key reactions.
Such reactions generally involve substrates converting into products. Enzymes speed up these reactions, making them efficient and feasible under biological conditions. These reactions are responsible for energy production, synthesis of biomolecules, and regulation of physiological functions. The coordination of specific biological chemical reactions is required to support growth, development, and adaptation to environmental changes.

• Enzymes: Act as catalysts to speed up reactions.
• Energy transformation: Critical in metabolism and growth.