Biomolecular Structure and Function
Macromolecules as Molecular Systems
Structure Determines Function
Biomolecules rely on intermolecular forces, conformational flexibility, and specific binding interactions. Proteins fold into shapes that create active sites, nucleic acids store information through base pairing, and lipids self-assemble due to amphipathic character.
Biomolecule Overview
| Class | Basic role | Structural feature |
|---|---|---|
| Proteins | Catalysis and structure | Amino acid sequence folds into 3D form |
| Nucleic acids | Information storage and transfer | Complementary base pairing |
| Lipids | Membranes and energy storage | Hydrophobic chains plus polar heads |
| Carbohydrates | Energy and recognition | Multiple hydroxyl groups |
What interaction most often stabilizes DNA base pairing?
Complementary bases are held together primarily by hydrogen bonds and stacking interactions.
Correct answer: Hydrogen bonding
Why do phospholipids form bilayers in water?
Polar heads interact with water while hydrophobic tails avoid it, producing bilayers.
Correct answer: their amphipathic nature drives self-assembly
Protein Folding and Binding
Noncovalent Forces in Biology
Protein folding is driven by the balance of hydrophobic effects, hydrogen bonding, ionic interactions, and van der Waals forces. Binding specificity arises because complementary shapes and chemical groups maximize favorable interactions.
Which force is especially important in driving protein cores away from water?
The hydrophobic effect favors burial of nonpolar groups inside proteins.
Correct answer: Hydrophobic effect
What is one reason enzyme active sites are specific?
Specificity arises from spatial and interaction matching between enzyme and substrate.
Correct answer: they are shape and chemistry complementary to the substrate