In-Depth Notes on Chemistry of Life, Elements and Water Properties

Assessing Prior Knowledge

  • Key Terms: KMT (Kinetic Molecular Theory), Matter
  • Importance of Water:
    • Water is essential to all living things.
    • Discuss THREE properties of water.

Properties of Water

  1. Cohesion: Attraction between water molecules.
    • Example: Surface tension, allowing insects to walk on water.
  2. Adhesion: Attraction between water molecules and other substances.
    • Example: Water movement in plants through capillary action.
  3. Temperature Moderation: Water has a high specific heat capacity.
    • Allows organisms to maintain stable internal temperatures.
    • Helps moderate climate by stabilizing temperatures.

Role of Water in Biological Processes

  • Metabolic Processes: Water acts as a solvent, facilitating biochemical reactions within cells.
  • Thermoregulation: Water absorbs and distributes heat, protecting organisms from extreme temperature fluctuations.
  • Plant Physiology: Water moves from roots to leaves through xylem, driven by transpiration and cohesive forces.

Chemistry of Life - Elements

  • Living systems require a constant input of energy for growth, reproduction, and homeostasis.
  • Important Elements:
    • Carbon: Fundamental for building macromolecules; forms the backbone of biological structures.
    • Nitrogen: Needed for synthesizing proteins and nucleic acids.
    • Phosphorus: Integral for nucleic acid structure and certain lipids.

Essential Knowledge

  • Macromolecules are composed of elements that exchange matter with the environment.
    • Carbon (C), Hydrogen (H), Nitrogen (N), Oxygen (O), Phosphorus (P), Sulfur (S) - collectively known as CHNOPS.
    • Organisms need these elements to maintain organization and perform life processes.

Atomic Structure

  • Atom: The basic unit of matter, consisting of protons, neutrons, and electrons.
  • Subatomic Particles:
    • Protons: Positive charge
    • Neutrons: No charge
    • Electrons: Negative charge

Elements and Compounds

  • Element: Pure substance consisting of one type of atom. (~20-24 essential for life)
  • Compound: Chemical combination of two or more elements in fixed proportions (e.g., Water - $H_2O$).

Chemical Bonds

  1. Ionic Bonds:
    • Formed by electron transfer between atoms.
    • Example: Na loses an electron to Cl, forming Na$^+$ and Cl$^-$, which attract each other.
  2. Covalent Bonds:
    • Electrons are shared between atoms.
    • Example: In water, each H shares electrons with O.

Polar and Nonpolar Molecules

  • Polar Molecules: Unequal sharing of electrons creates charged regions (e.g., Water).
  • Nonpolar Molecules: Equal sharing among identical atoms (e.g., O$2$, N$2$).

Solutions and Suspensions

  • Solution: Homogeneous mixture of solute and solvent (e.g., salt in water).
  • Suspension: Mixture of water and undissolved materials (e.g., blood).

Acids, Bases, and pH

  • pH Scale: Ranges from 0 (acidic) to 14 (basic).
    • Neutral: pH = 7 (pure water).
    • Acids: pH < 7 (e.g., lemon juice).
    • Bases: pH > 7 (e.g., bleach).
  • Buffers: Stabilize pH in biological systems, essential for proper cellular function.

Carbon's Role in Life

  • Carbon can bond with other elements and itself, forming chains/rings crucial for macromolecules:
    • Carbohydrates: Energy storage, cell structure.
    • Proteins: Made of amino acids; essential for bodily functions.
    • Nucleic Acids: DNA and RNA, genetic coding.
    • Lipids: Energy storage, cell membrane components.

Questions to Consider

  1. What are the subunits (monomers) for each type of macromolecule?
  2. How do organisms obtain the matter needed for subunits and macromolecules?
  3. Explain nitrogen and phosphorus's roles in biological macromolecules?
  4. Describe the structure and function of nucleic acids and lipids regarding phosphorus.