Overview
This lecture focused on enzymes, their functions, properties, and significance in biological processes as covered in Bio 202 Chapter 3CD.
Enzyme Structure and Function
- Enzymes are biological catalysts that speed up chemical reactions in cells.
- Each enzyme is specific to one substrate due to its unique active site.
- The enzyme-substrate complex is formed when a substrate binds to the enzyme's active site.
- Enzymes lower the activation energy required for reactions.
- Enzyme activity can be affected by temperature, pH, and substrate concentration.
- Most enzymes are proteins, but some RNA molecules can act as enzymes (ribozymes).
Enzyme Regulation
- Enzyme function can be regulated by inhibitors or activators.
- Competitive inhibitors bind to the active site, blocking the substrate.
- Noncompetitive inhibitors bind elsewhere on the enzyme, changing its shape and reducing activity.
- Allosteric regulation involves molecules binding to sites other than the active site to change enzyme activity.
- Feedback inhibition occurs when the end product of a pathway inhibits an earlier enzyme in the pathway.
Importance of Enzymes in Metabolism
- Enzymes are crucial in metabolic pathways for efficient biochemical reactions.
- Without enzymes, metabolic reactions would occur too slowly to sustain life.
Key Terms & Definitions
- Enzyme — protein catalyst that increases the rate of biochemical reactions.
- Active Site — region on the enzyme where the substrate binds.
- Substrate — molecule upon which an enzyme acts.
- Enzyme-Substrate Complex — temporary complex formed when an enzyme binds its substrate.
- Activation Energy — energy required to initiate a chemical reaction.
- Inhibitor — molecule that decreases enzyme activity.
- Allosteric Site — location on an enzyme where a regulator molecule binds, affecting function.
Action Items / Next Steps
- Review textbook sections on enzyme structure and function.
- Complete assigned homework on enzyme action and regulation.