🌱 Biology : Chapter 1: To Life Processes

📘 Chapter Title: To Life Processes

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🔍 Summary (150–250 words)

The chapter "To Life Processes" provides an introduction to the vital biological processes that sustain life in all organisms. It emphasizes the idea that life is a continuous sequence of chemical reactions, collectively known as metabolism. These processes ensure organisms obtain and utilize energy, maintain internal stability, and adapt to their environment.

The chapter explains the two main aspects of metabolism: anabolism (constructive processes like photosynthesis) and catabolism (destructive processes like respiration). It describes how biomolecules such as carbohydrates, proteins, fats, and nucleic acids are essential for metabolic reactions. The importance of enzymes as catalysts and hormones as regulators is also highlighted.

The concept of homeostasis is introduced as a vital mechanism to maintain a stable internal environment. Additionally, the chapter details how the plasma membrane plays a critical role in regulating the exchange of substances through mechanisms like diffusion, osmosis, facilitated diffusion, and active transport.

By linking molecular activities to cellular and systemic functions, this chapter lays the foundation for understanding broader biological functions such as respiration, digestion, circulation, and excretion. It serves as a base for all further exploration into the life processes that define living organisms.

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📌 Capsule Notes

🔹 Metabolism

• Metabolism = Anabolism + Catabolism.

  • Anabolism: Building complex molecules (e.g., photosynthesis).

  • Catabolism: Breaking down molecules (e.g., respiration).

• Requires biomolecules like:

  • Carbohydrates → Energy source.

  • Proteins → Structural & functional roles.

  • Lipids → Stored energy.

  • Nucleic acids → Genetic information.

🔹 Enzymes & Hormones

• Enzymes:

  • Biological catalysts.

  • E.g., Salivary amylase breaks down starch.

• Hormones:

  • Regulate metabolism.

  • E.g., Insulin regulates glucose level.

🔹 Internal Environment & Homeostasis

• Internal Environment:

  • Fluid surrounding cells in multicellular organisms.

• Homeostasis:

  • Maintaining stable internal conditions (e.g., body temperature, pH).

🔹 Plasma Membrane & Transport Mechanisms

• Plasma Membrane: Selectively permeable; regulates entry/exit.

• Transport mechanisms:

  • Diffusion: Movement of molecules from high to low concentration.

  • Osmosis: Movement of water through a semi-permeable membrane.

  • Facilitated Diffusion: Via channel proteins, passive.

  • Active Transport: Against concentration gradient using energy.

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❓ Q&A – Questions with Answers

1. Define metabolism.
   → Metabolism is the sum of all chemical reactions occurring in a cell or organism.

2. What are the two types of metabolic processes?
   → Anabolism and catabolism.

3. Give an example of an anabolic process.
   → Photosynthesis.

4. Name one catabolic process.
   → Cellular respiration.

5. What are biomolecules?
   → Molecules like carbohydrates, proteins, lipids, and nucleic acids required for metabolism.

6. What is the role of enzymes in metabolism?
   → Enzymes act as biological catalysts that speed up reactions.

7. Define homeostasis.
   → The process of maintaining a stable internal environment in the body.

8. What is the internal environment in humans?
   → The fluid surrounding cells (tissue fluid).

9. What is the function of the plasma membrane?
   → It controls the movement of substances in and out of the cell.

10. Differentiate between osmosis and diffusion.
    → Osmosis is the movement of water; diffusion is the movement of any substance from high to low concentration.

11. What is facilitated diffusion?
    → Passive transport of molecules via proteins in the membrane.

12. Which process requires energy: diffusion or active transport?
    → Active transport.

13. How do lipids help in metabolism?
    → They act as a long-term energy storage.

14. Give one function of hormones in life processes.
    → They regulate and control metabolic activities.

15. Name two components of the plasma membrane.
    → Proteins and phospholipids.

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📚 Definitions & Key Terms

• Metabolism: Total of all chemical reactions in a living organism.

• Anabolism: Energy-consuming synthesis of complex molecules.

• Catabolism: Energy-releasing breakdown of molecules.

• Biomolecules: Chemical compounds involved in metabolism (e.g., carbohydrates, proteins).

• Enzyme: A biological catalyst speeding up metabolic reactions.

• Hormone: A chemical messenger that regulates bodily functions.

• Homeostasis: The maintenance of internal stability.

• Plasma Membrane: A semi-permeable membrane controlling material exchange.

• Diffusion: Movement of molecules from high to low concentration.

• Osmosis: Movement of water across a semi-permeable membrane.

• Facilitated Diffusion: Transport through protein channels, without energy.

• Active Transport: Movement against concentration gradient, requires energy.

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🧠 Main Points for Revision

• Metabolism = All chemical reactions in the body.

• Anabolism builds up; Catabolism breaks down.

• Biomolecules: Carbs = energy, Proteins = structure, Lipids = storage, Nucleic acids = genetic code.

• Enzymes = Catalysts; Hormones = Regulators.

• Homeostasis = Constant internal environment.

• Transport:

  • Diffusion = Passive.

  • Osmosis = Water-specific.

  • Facilitated diffusion = Uses protein channels.

  • Active transport = Needs energy.

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📂 Topic-Wise Breakdown

1. Introduction to Life Processes

• Metabolism overview.

• Importance of energy transformation.

2. Biomolecules

• Carbohydrates, proteins, lipids, nucleic acids.

• Role in cellular activities.

3. Enzymes and Hormones

• Enzymes = Catalysts.

• Hormones = Regulators of metabolism.

4. Internal Environment

• Homeostasis defined.

• Examples: temperature, water balance.

5. Plasma Membrane

• Structure and function.

• Selective permeability.

6. Transport Mechanisms

• Passive: Diffusion, osmosis, facilitated diffusion.

• Active: Energy-requiring transport.