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Chapter 3: The Chemical Level of Organization

Introduction

  • This chapter explores the fundamental chemistry concepts relevant to the human body including:

    • Matter

    • Atoms and molecules

    • Chemical bonds

    • Inorganic and organic compounds

Icebreaker Questions

  • What molecules are present in the human body?

  • Define organic molecules.

  • What are the chemical reactions necessary for life?

  • Locations of molecules in living organisms?

Section 3.1: Elements and Atoms

Basic Definitions

  • Matter: Anything occupying space and having mass (not weight).

  • Mass: Amount of matter in an object, consistent regardless of gravity.

Elements and Compounds

  • Elements: Pure substances, single type of atom.

  • Atoms: Smallest unit retaining properties of an element.

  • Molecules: Two or more atoms chemically bonded.

  • Compounds: Two or more different elements chemically combined.

Section 3.2: Chemical Bonds

Types of Bonds

  1. Ionic Bonds: Formed between charged ions (cations and anions) with opposite charges. Example: Sodium chloride (NaCl).

  2. Covalent Bonds: Formed by sharing electrons. Can be:

    • Nonpolar Covalent: Equal sharing of electrons.

    • Polar Covalent: Unequal sharing of electrons, resulting in partial charges.

  3. Hydrogen Bonds: Non-covalent attractions between molecules, like those in water, contributing to properties such as high surface tension.

Electron Behavior

  • Electron Shells: Regions where electrons reside; filled shells lead to stability.

  • Valence Shell: Outermost shell; its stability strongly influences chemical reactivity.

Section 3.3: Chemical Reactions

Role of Energy in Reactions

  • **Energy Forms: **

    • Potential energy: Stored energy.

    • Kinetic energy: Energy of motion;

    • Chemical energy: Energy in chemical bonds.

    • Exergonic Reactions: Release energy.

    • Endergonic Reactions: Absorb energy; typically require input to occur.

Types of Reactions

  1. Synthesis Reactions: Combine reactants to form products.

  2. Decomposition Reactions: Break down compounds into simpler components.

  3. Exchange Reactions: Involve both synthesis and decomposition.

Section 3.4: Inorganic Compounds

Inorganic vs. Organic Compounds

  • Inorganic Compounds: Lack carbon and hydrogen. Examples include water, salts, acids, and bases.

  • Organic Compounds: Contain carbon and hydrogen, comprising key macromolecules (carbohydrates, lipids, proteins, nucleic acids).

Role of Water in the Body

  • Comprises 50-70% of body mass.

  • Functions include:

    • Joint lubrication.

    • Cushioning cells.

    • Temperature regulation.

    • Solvent for ions and nutrients.

Solutions and Solubility

  • Solution: A mixture of solute and solvent (e.g., nutrients dissolved in water).

  • Water as a universal solvent supports numerous biochemical processes.

Section 3.5: Organic Compounds

Types of Biological Macromolecules

  1. Carbohydrates: Energy source, with monomers being monosaccharides.

    • Types: Monosaccharides, disaccharides, polysaccharides.

  2. Lipids: Primarily energy storage molecules, including triglycerides, which provide insulation.

  3. Proteins: Composed of amino acids; involved in structure, transport, and catalysis.

  4. Nucleic Acids: DNA and RNA responsible for genetic information and protein synthesis.

Enzymes and Catalysis

  • Enzymes are biological catalysts facilitating chemical reactions by lowering activation energy.

  • Specificity for substrates is determined by the enzyme's active site, allowing for efficient reaction processes.

Summary of Chapter 3

  • Understanding of chemistry's language and concepts as they relate to the human body.

  • Recognition of matter organization and chemical bonding.

  • Awareness of essential inorganic and organic compounds in physiological processes.

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