Importance of Water in Living Organisms

Importance of Water in Living Organisms

• Water is the most abundant molecule in the body, making up 60% of an adult's body weight, and is essential for life.
• Water is a universal solvent, enabling easy interactions between molecules without forming strong ionic or covalent bonds.
• It is possible to survive without food for over a month, but dehydration can lead to death within a week.
• Water is a reactant and plays a crucial role in maintaining a stable pH and electrolyte balance.

Characteristics of Life

• Life is characterized by regular structure, reproduction, growth, response to environment, energy processing, regulation, and evolutionary adaptation.
• These characteristics are essential for life to exist and thrive.

Hierarchy of Life

• Biome: The entire ecosystem on Earth, including water, land, and air.
• Ecosystem: A specific region with all living organisms, water, land, and air.
• Community: All living organisms within an ecosystem.
• Population: A group of individuals of the same species.
• Organism: A single living being.
• Organ and organ systems: Functional units within an organism.
• Tissue: A group of similar cells.
• Cell: The basic unit of life.
• Organelle: A subcellular structure with specific functions.
• Molecule: A group of atoms.
• Atom: The smallest unit of matter.

Molecular Composition of the Body

• In a 65 kg person, the body composition is:
  • Water: 61.6% (40 kg)
  • Protein: 17.0% (11 kg)
  • Lipid: 13.8% (9 kg)
  • Minerals: 6.1% (4 kg)

Elemental Composition of the Body

• Macro elements: O, C, H, N, Ca, P, K, S, Na, Cl, Mg
• Micro elements (trace elements): essential for bodily functions, but present in small amounts