Unit 10: Atoms, Compounds, and Microbiology

1. Basic Chemistry in Biology

  • Atoms: Smallest unit of matter, made up of protons (+), neutrons (0), and electrons (-).

  • Elements: Pure substances consisting of only one type of atom (e.g., Carbon, Oxygen).

  • Compounds: Two or more elements chemically combined (e.g., H₂O, CO₂).

2. Chemical Reactions in Biology

  • Reactants → Products (Substances change in a reaction).

  • Types of reactions important in biology:

    • Synthesis: Small molecules → Larger molecules (e.g., protein formation).

    • Decomposition: Large molecules → Smaller molecules (e.g., digestion).

    • Oxidation-Reduction: Transfer of electrons (e.g., cellular respiration).

3. Water and pH

  • Water’s Properties:

    • Cohesion (sticks to itself) and adhesion (sticks to other substances).

    • High heat capacity (regulates temperature).

    • Universal solvent (dissolves many substances).

  • pH Scale:

    • Measures how acidic/basic a substance is (0-14).

    • Acids (0-6.9): High H⁺ concentration (e.g., stomach acid).

    • Bases (7.1-14): High OH⁻ concentration (e.g., soap).

    • Neutral (7.0): Pure water.

4. Pathogens and Bacterial Growth

  • Pathogens: Microorganisms that cause disease (e.g., bacteria, viruses, fungi).

  • Bacterial Growth:

    • Binary fission: Bacteria reproduce by splitting into two identical cells.

    • Growth is exponential but limited by resources, competition, and antibiotics.

5. Microbiomes and Their Role in Health

  • Microbiome: Community of microorganisms living in a specific environment (e.g., gut, skin).

  • Importance of microbiomes:

    • Aid in digestion and vitamin production.

    • Protect against harmful pathogens.

    • Influence immune system function.

  • Disruptions (e.g., antibiotics) can lead to imbalances, causing infections or digestive issues.

6. Food Microbiology

  • Role of Microorganisms in Food Production:

    • Fermentation (e.g., yogurt, cheese, bread).

    • Preservation (e.g., pickling, curing).

  • Foodborne Illnesses:

    • Caused by bacteria (e.g., Salmonella, E. coli), viruses, or fungi.

    • Prevention: Proper cooking, hygiene, and refrigeration.

Connections to Previous Units:

  • Chemical reactions (Unit 4) are essential for metabolism and energy production.

  • Water’s role ties into environmental cycles (Unit 6).

  • Microbiomes influence human homeostasis (Unit 5).