Lecture Notes: Chemical Levels of Organization

Introduction

• Role of Chemistry in Life:
  • Chemistry explains the structure of matter.
  • Matter is anything that has mass and occupies space.
  • Importance of understanding elements and atoms.

Basic Concepts

• States of Matter:
  • Solid, Liquid, Gas.
• Elements and Atoms:
  • Elements are unique substances that cannot be broken down by ordinary chemical means.
  • Atoms are the smallest stable units of matter, make up elements.
  • 91 naturally occurring elements, 24 essential for human physiology.

Atomic Structure

• Major Atomic Particles:
  • Protons: Positively charged, have mass.
  • Neutrons: No charge, have mass.
  • Electrons: Negatively charged, negligible mass.
• Atomic Number and Mass Number:
  • Atomic number = number of protons.
  • Mass number = protons + neutrons.
• Isotopes:
  • Atoms with the same number of protons but different neutrons.

Chemical Bonds

• Orbitals and Electron Shells:
  • Electrons revolve around nucleus in shells/orbitals.
  • Stability depends on full electron shells.
• Types of Bonds:
  • Ionic: Transfer of electrons, formation of ions.
  • Covalent: Sharing of electrons, can be polar or nonpolar.
  • Hydrogen: Weak attractions between slightly charged atoms.

Inorganic and Organic Compounds

• Inorganic Compounds:
  • Do not contain C-H bonds.
  • Examples: Water, CO2.
• Organic Compounds:
  • Contain carbon-hydrogen bonds.
  • Classes: Carbohydrates, Lipids, Proteins, Nucleic Acids.

Chemical Reactions

• Types of Reactions:
  • Combination, Decomposition, Exchange.
• Factors Affecting Reaction Rate:
  • Temperature, particle size, concentration, catalysts.

pH and Buffers

• pH Scale:
  • 0-14, 7 is neutral.
  • Lower pH is acidic, higher pH is basic.
• Buffers:
  • Stabilize pH by managing hydrogen ions.
  • Example: Carbonic acid-bicarbonate buffer system.

Organic Molecules

• Carbohydrates:
  • Main energy source.
  • Types: Monosaccharides, Disaccharides, Polysaccharides.
• Lipids:
  • Hydrophobic, energy storage, cell membrane structure.
  • Types: Fatty acids, triglycerides, phospholipids, steroids.
• Proteins:
  • Made of amino acids, structural support, enzymes.
  • Structure types: Primary, Secondary, Tertiary, Quaternary.
• Nucleic Acids:
  • DNA and RNA, store and transfer genetic information.
  • Made of nucleotides with nitrogenous base, sugar, phosphate.

ATP

• Adenosine Triphosphate (ATP):
  • Major energy currency of the cell.
  • Consists of adenine, ribose sugar, three phosphate groups.

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These notes provide a summary of the key concepts and points covered in the lecture on chemical levels of organization, including the basic understanding of chemistry's role in life, atomic structure, types of chemical bonds, differences between organic and inorganic compounds, and the importance of pH and buffers in biological systems.