Chemical Level of Organization

Matter and Mass

• Matter: Anything with mass and occupies space.
  • States of matter: Solid, Liquid, Gas.
• Mass: Quantity of matter, determines weight in Earth's gravity.
  • Mass = Amount of material in matter.
  • For course purposes, mass = weight.

States of Matter

• Solid: Definite shape and volume.
• Liquid: Definite volume, changeable shape.
• Gas: Changeable shape and volume.
• Water: Exists in all three states (ice, water, vapor).

Elements

• Composed of elements, cannot be broken down by ordinary means.
• Have unique physical (sensory, measurable) and chemical properties (bonding).
• Major Elements in Human Body:
  • Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N)
  • Lesser elements: Calcium (Ca), Phosphorus (P), Potassium (K), Sodium (Na), Chlorine (Cl), etc.
  • Trace elements: Zinc, Chromium, Manganese, etc.

Atomic Structure

• Atoms: Smallest stable units of matter.
  • Composed of subatomic particles.
  • Nucleus: Protons (+), Neutrons (no charge)
  • Electrons: Orbit nucleus, negative charge.

Models of Atomic Structure

• Planetary Model
• Electron Cloud Model
  • Electron shells important for chemical reactions.

Molecules and Compounds

• Molecules: Atoms interacting, larger structures.
• Compounds: Atoms from different elements.
• Atomic Number: Number of protons.
• Mass Number: Protons + Neutrons.
• Isotopes: Same protons, different neutrons.
  • Radioactive isotopes decay, used in research/medicine.

Chemical Bonds

• Ionic Bonds: Transfer of electrons.
  • Form cations (+) and anions (-).
  • Example: Sodium Chloride (NaCl).
• Covalent Bonds: Sharing of electrons.
  • Can be single, double, or triple bonds.
  • Polar vs. Nonpolar bonds (e.g., water is polar).

Chemical Reactions and Energy

• Chemical Reactions: Making or breaking chemical bonds.
  • Metabolism: All reactions in the body.
• Energy Types: Kinetic (motion), Potential (stored).
  • Energy can change forms but not created/destroyed.

Types of Reactions

• Synthesis (Combination): Form larger molecules.
• Decomposition: Break down molecules.
• Exchange: Making and breaking bonds.
• Enzymes: Catalysts, lower activation energy.

Organic vs. Inorganic Compounds

• Organic Compounds: Contain carbon, covalent bonds.
  • Carbohydrates, proteins, lipids, nucleic acids.
• Inorganic Compounds: Typically do not contain carbon.

Important Biological Molecules

• Carbohydrates: Major fuel source, structural role.
  • Monosaccharides, Disaccharides, Polysaccharides.
• Lipids: Insoluble in water, energy storage, cellular structure.
  • Fatty acids, Triglycerides, Phospholipids, Steroids.
• Proteins: Composed of amino acids.
  • Levels of structure: Primary, Secondary, Tertiary, Quaternary.
• Nucleic Acids: DNA and RNA, genetic material.
  • ATP as the energy currency of the cell.