BIO151 Lecture 5 Carbon Biological Molecules

Page 1: Introduction

  • Lecture Topic: Carbon & Biological Molecules

  • Course: Biology 151 Lecture 5

  • Date: January 31, 2025

  • Instructor: Friedrich

Page 2: Definition of Molecules

  • Molecule Definition: Not explicitly defined in the text.

  • Examples of molecules:

    • Methane (CH4)

    • Ammonia (NH3)

    • Water (H2O)

    • Carbon Dioxide (CO2)

  • Types of Formulas:

    • Molecular Formulas: indicates the number of each type of atom.

    • Structural Formulas: shows the arrangement of atoms (example: H-N-H for ammonia).

    • Ball-and-Stick Models: represent molecular geometry visually.

    • Space-Filling Models: show the relative sizes of atoms in a molecule.

Page 3: Periodic Table Highlights

  • Key Elements:

    • Hydrogen (H): Atomic number 1, atomic weight 1.0079

    • Helium (He): Atomic number 2, atomic weight 4.0026

    • Other important elements highlighted: Li, Be, B, C, N, O, F, Ne (and more up to Rn, element number 86).

Page 4: Biological and Organic Molecules

  • Biological Molecules: Produced by living organisms; contain carbon atoms, with exceptions like water.

  • Organic Compounds: Compounds containing carbon; term not related to agricultural "organic" produce.

Page 5: Carbon: The Backbone of Life

  • Covalent Bonds: Formed when atoms react to fill partially filled electron shells. Carbon has four electrons in its outer shell, allowing for:

    • Extensive bonding versatility.

    • A stable outer shell achieved with 8 electrons.

  • Importance of Carbon: Facilitates formation of large and complex molecules crucial for life.

Page 6: Common Elements in Organic Molecules

  • Key elements forming biological molecules:

    • Carbon (C)

    • Hydrogen (H)

    • Nitrogen (N)

    • Oxygen (O)

  • Significance: The variety in biological molecules arises from carbon's bonding flexibility.

Page 7: Carbon Chains

  • Carbon Chains: Serve as the skeleton for organic molecules, which can vary by:

    • Length

    • Branching Patterns

    • Presence of Rings

    • Double Bond Positions

    • Examples: Ethane, Propane, Butanes, Cyclohexane, Benzene.

Page 8: Hydrocarbons

  • Definition: Composed exclusively of carbon and hydrogen (H and C).

  • Examples include Ethane, Propane, and various forms of Butanes.

Page 9: Functional Groups

  • Functional Groups: Atoms or groups of atoms that replace hydrogens in organic skeletons, affecting function and reactions of molecules.

Page 10: Functional Groups Summary

  • Six Common Functional Groups:

    • Amino (H-N-R): Basic properties, example: Glycine.

    • Carboxyl (R-C(=O)OH): Acidic properties, example: Acetic acid.

    • Carbonyl (C=O): Forms larger molecules, example: Acetaldehyde.

    • Hydroxyl (R-OH): Polar, example: Ethanol.

    • Phosphate: Energy storage, example: 3-Phosphoglyceric acid.

    • Sulfhydryl (R-SH): Contributes to protein structure, example: Cysteine.

Page 19: Hydrophilic and Hydrophobic

  • Hydrophilic: "Water-loving" molecules, usually polar or charged (example: Glucose).

  • Hydrophobic: "Water-fearing" molecules, generally non-polar or uncharged.

Page 27: Carbon's Significance

  • Diversity: Nearly 10 million carbon compounds identified; crucial to life.

  • Carbon in the Body: Makes up about 20% by weight.

  • Natural Forms: Diamonds (hardest) and graphite (softest), both comprised entirely of carbon.

  • Carbon Utilization: Plants and animals use carbon for energy; carbon dating is used for age measurement of deceased organisms.

  • Fossil Fuels: Coal, oil, and gas are primarily concentrated carbon derivatives from ancient biological sources.