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L4 chemistry of life

Chemistry and Life on Mars

What is Life?

  • Essentials for Life:

    • Reproduction: The ability to reproduce.

    • Maintenance: Sustaining stable internal conditions (homeostasis).

    • Response: Ability to respond to environmental stimuli.

    • Evolution: Capacity for change over generations.

    • Variation: Possession of genetic diversity.

    • Selection: Natural selection acting on variations.

Perspectives on Life

  • Examples of Life:

    • A rock

    • A metabolically active compartment (e.g., mitochondria)

    • A bacterium

    • A seed

    • A virus

  • Shared Building Blocks: All forms of life share fundamental physical elements. Life originated from chemistry.

The Emergence of Life from Nonliving Matter

  • Key components for life include:

    • Glucose: A simple sugar vital for energy.

    • Glutamine: An amino acid essential for protein synthesis.

    • DNA: The molecule that carries genetic information.

    • Triacylglycerol: A fat molecule important for energy storage.

Understanding Emergence

  • Emergence: Complicated behaviors and patterns can develop from simple rules.

    • Examples:

      • A school of fish.

      • Chromosome segregation during cell division.

    • Self-organization in biological systems leads to complex interactions at cellular levels.

Requirements of Life

Key Requirements:

  • Energy: Essential for all biological functions.

Structure and Composition of Life

  • Building Blocks: What are the fundamental materials of life?

Elements Fundamental to Life

  • Abundance of Key Elements:

    • Life comprises various essential elements including:

      • Oxygen

      • Carbon

      • Hydrogen

      • Nitrogen

      • Other trace elements.

The Atoms and Molecules of Life

  • Role of Carbon:

    • Carbon serves as the molecular backbone for most life-essential molecules.

    • Water (H2O): A crucial component supporting life processes.

Why Carbon?

  • Carbon-Based Life: All known life forms are based on carbon due to its versatile bonding capacity:

    • Can form up to four stable covalent bonds.

    • Small size and unique electron configuration aid bonding.

Overview of Chemical Bonds

  • Types of Bonds:

    • Ionic Bonds: Formed by transferring electrons.

    • Covalent Bonds: Formed by sharing electrons (e.g., Methane, CH4).

Carbon’s Electron Configuration

  • Valence Electrons: Carbon possesses four valence electrons, allowing the formation of varied compounds by sharing or structuring these bonds to achieve stability.

Levels of Organization in Biological Chemistry

  • Molecular Interactions: Chemistry of life involves strong covalent bonds and weaker intermolecular forces such as hydrogen bonds.

Biological Membranes

  • Characteristics:

    • Impermeability: Membranes restrict passage of polar molecules.

    • Functionality: Define cellular compartments and boundaries.

  • Cellular Dynamics: Understanding these membranes is key to comprehending cellular structure and function.