Bio 1 Unit 2 Study Guide (comprehensive)

Detailed Overview of Protein Structure and Enzyme Functionality

Protein Structure

• Proteins are complex macromolecules essential for biological functions.

• Described at four primary levels:

  • Primary Structure:

    • Unique sequence of amino acids linked by peptide bonds.

    • Determines specific properties and functions of the protein.

  • Secondary Structure:

    • Arises from hydrogen bonding between amino acids.

    • Forms include:

      • α-helix: Coiled structure stabilized by hydrogen bonds.

      • β-sheet: Sheet-like structures with hydrogen bonds between strands (can be parallel or antiparallel).

  • Tertiary Structure:

    • Three-dimensional folding of a polypeptide chain.

    • Influenced by interactions among R-groups:

      • Hydrophobic interactions

      • Hydrogen bonds

      • Ionic interactions

      • Disulfide bridges (covalent bonds between cysteine residues)

    • Crucial for protein functionality, determining active site and shape.

  • Quaternary Structure:

    • Consists of multiple polypeptide chains or subunits.

    • Arrangement and interaction enhance functionality.

Enzymes: Biological Catalysts

• Enzymes are specialized proteins that catalyze reactions, lowering activation energy.

• Active Site:

  • Region where substrate binding occurs.

  • Tailored shape and chemical environment to facilitate conversion of substrates into products.

• Enzyme Specificity:

  • Enzymes act on specific substrates