Week 2 ; Pt 1 - Structure of Biological Macromolecules

Functional Groups in Chemistry

• Functional Groups: Characteristic atoms or groups of atoms in a molecule responsible for chemical reactions.
  • Examples: -OH (hydroxyl), -COOH (carboxyl), -NH2 (amine).

Carbon Structure and Bonding

• Classification of Carbon Atoms:
  • Primary (1o): Carbon bonded to 1 other carbon.
  • Secondary (2o): Carbon bonded to 2 other carbons.
  • Tertiary (3o): Carbon bonded to 3 other carbons.
  • Quaternary (4o): Carbon bonded to 4 other carbons.

Types of Hydrocarbons

• Saturated Hydrocarbons (Alkanes):

  • General Formula: CₙH₂ₙ₊₂.
  • Carbon connected only by single bonds.
  • Examples: Methane (CH₄), Ethane (C₂H₆).

• Unsaturated Hydrocarbons:

  • Alkenes (Double Bonds):
  • General Formula: CₙH₂ₙ.
  • Example: Ethene (C₂H₄).
  • Alkynes (Triple Bonds):
  • General Formula: CₙH₂ₙ₋₂.
  • Example: Ethyne (C₂H₂).

IUPAC Nomenclature

• Naming Compounds:
  1. Prefix: Number of carbon atoms.
  2. Infix: Type of carbon-carbon bonds.
  3. Suffix: Class of compound.
• Branching Rules:
  1. Longest carbon chain is the parent chain.
  2. Numbering starts at the end nearest the substituent.

Alcohols

• Contain -OH (hydroxyl) group.
• Dipole-Dipole Interactions:
  • Attraction between positive and negative ends of dipoles.
• Hydrogen Bonding:
  • Strong interactions due to H bonded to electronegative atoms (F, O, N).
• Example: Ethanol (C₂H₅OH).

Amines

• Functional Group: -NH₂ (amine).
• Polar, can form hydrogen bonds.
  • Classification:
  • Primary (1o): 1 carbon.
  • Secondary (2o): 2 carbons.
  • Tertiary (3o): 3 carbons.

Aldehydes and Ketones

• Aldehydes: Carbonyl group (C=O) bonded to H.
  • Naming: Suffix -al (e.g., Methanal).
• Ketones: Carbonyl group bonded to two carbons.
  • Naming: Suffix -one (e.g., Propanone).

Carboxylic Acids

• Functional Group: -COOH (carboxyl).
• Naming: Suffix -oic acid (e.g., Ethanoic acid).
• Form hydrogen bonds.

Esters and Amides

• Esters: Carbonyl group attached to an -OR group.
  • Naming: -oate (e.g., Ethyl ethanoate).
• Amides: Carbonyl group attached to a nitrogen atom.
  • Naming: -amide (e.g., Ethanamide).

Summary

• Understanding functional groups is crucial for predicting chemical behavior and properties of organic molecules.
• Familiarity with nomenclature allows for easier identification and communication of chemical compounds.