Biodegradable Substances MCQs Quiz | Class 10

Understanding Biodegradable Substances

Welcome to the detailed learning section on Biodegradable Substances! After testing your knowledge, let’s consolidate your understanding of this important topic from Class X Science.

Overview

Biodegradable substances are materials that can be broken down naturally by biological processes, primarily through the action of microorganisms such as bacteria and fungi. This natural decomposition process is vital for maintaining ecological balance and nutrient cycling within ecosystems. Unlike non-biodegradable substances, which persist in the environment for very long periods, biodegradable materials naturally return to the environment as simpler compounds, enriching the soil and completing natural cycles.

Key Concepts

1. Definition

Biodegradable substances are those that can be decomposed or broken down into simpler, harmless substances by the action of living organisms (decomposers) over a period of time. This breakdown is a natural process.

2. Examples

Common examples include:

• Plant-based materials: Vegetable peels, fruit remains, leaves, wood, paper, cotton, jute.
• Animal-based materials: Animal waste, dead plants and animals, wool, leather.
• Food waste: Leftover food, bread, meat scraps.

These materials are rich in organic compounds that microorganisms can metabolize.

3. Decomposition Idea

The process of decomposition is a complex biological reaction.

• Role of Decomposers: Bacteria and fungi are the primary decomposers. They secrete enzymes that break down complex organic molecules (like cellulose, proteins, fats) into simpler inorganic substances (carbon dioxide, water, nitrates, phosphates).
• Factors Affecting Decomposition:
  • Moisture: Water is essential for microbial activity.
  • Temperature: Decomposers thrive in warm, not extreme, temperatures.
  • Oxygen (Aerobic Decomposition): Many decomposers require oxygen. This process is generally faster and produces carbon dioxide and water.
  • Lack of Oxygen (Anaerobic Decomposition): In the absence of oxygen, decomposition is slower and can produce methane (a potent greenhouse gas) and other organic acids.
  • pH: Most decomposers prefer a neutral to slightly acidic pH.
  • Presence of Nutrients: Microorganisms need nitrogen, phosphorus, and other elements to grow and reproduce.

Table: Decomposition Times for Common Biodegradable Items

Environmental Significance

The decomposition of biodegradable waste is crucial for:

• Nutrient Cycling: It returns essential nutrients to the soil, supporting plant growth and overall ecosystem health.
• Waste Management: It helps reduce the volume of waste in landfills.
• Compost Production: Decomposed organic matter forms compost, a valuable natural fertilizer.

Quick Revision Checklist

• Definition: Can break down naturally by microbes.
• Examples: Vegetable peels, paper, wood, cotton.
• Decomposers: Bacteria, fungi.
• Key Factors: Moisture, temperature, oxygen.
• Benefit: Nutrient return to soil, waste reduction.

Practice Questions (for further study)

1. Explain the difference between biodegradable and non-biodegradable substances with two examples of each.
2. Describe the role of microorganisms in the decomposition process.
3. List three environmental factors that influence the rate of decomposition.
4. Why is it important to segregate biodegradable and non-biodegradable waste at home?
5. What is composting, and how does it help in managing biodegradable waste?

This section provides a comprehensive look at biodegradable substances, reinforcing the concepts covered in your quiz. Keep learning!