Macromolecules and Enzyme Function
Major Macromolecule Classes
The four major classes
Cells build four main macromolecule classes: proteins, nucleic acids, carbohydrates, and lipids. Each class has distinct monomers, bonding patterns, and biological roles.
Macromolecule summary
Mechanism focus
The same chemical building block can serve many roles depending on how it is connected and folded.
Protein structure and function
Protein structure is hierarchical: primary, secondary, tertiary, and quaternary. Folding is driven by interactions among side chains, including hydrophobic effects, hydrogen bonds, ionic interactions, and disulfide bridges.
Which level of protein structure is determined directly by the amino acid sequence?
The amino acid sequence is the primary structure and determines higher-order folding indirectly.
Correct answer: Primary structure
What is the main catalytic role of enzymes?
Enzymes stabilize transition states and reduce the energy barrier for reactions.
Correct answer: They lower activation energy to speed up reactions without being consumed.
DNA vs RNA
DNA
- Deoxyribose sugar
- Usually double-stranded
- Long-term information storage
RNA
- Ribose sugar
- Usually single-stranded
- Information transfer and regulation
Why do enzymes often show specificity for one substrate or a small set of substrates?
Substrate specificity comes from the structure and chemical environment of the active site.
Correct answer: Their active sites have complementary shape and chemistry