Unit 1.3 Notes: Enzymes in Detail

Introduction

• Final set of notes in Unit 1.
• Focus on enzymes, their structure, and function within living organisms.
• Three key topics, focusing mainly on Topic 1 in this lecture.

Enzymes Overview

• Enzymes: Proteins that catalyze chemical reactions to occur fast and efficiently within cells.
• Enzymes are proteins with specific shapes that facilitate specific reactions.

Chemical Reactions Refresher

• Chemical Reactions: Transformation of starting molecules (reactants) into new molecules (products) by breaking and reforming chemical bonds.
• Example: Photosynthesis, where CO2 and H2O are converted into glucose and O2.
• Chemical Equation: Represents the summary of reactants and products.

Activation Energy

• Activation Energy: Energy that reactants must absorb to initiate a chemical reaction.
• Represented on an energy diagram showing the energy change during a reaction.
• Reactions with high activation energy occur slowly; low activation energy reactions occur quickly.

Role of Enzymes

• Enzymes: Proteins acting as catalysts by lowering activation energy, increasing the reaction rate.
• Catalysts: Substances that increase reaction rates by reducing activation energy.

Enzyme Function and Structure

• Enzymes are proteins made from amino acids forming a specific shape.
• Active Site: Specific region where the enzyme binds to the substrate (reactants).
• Induced Fit: Enzyme changes shape slightly to embrace the substrate tightly.

Enzyme-Substrate Complex

• Substrates: Reactants that an enzyme binds to.
• Enzyme-Substrate Complex: Formed when an enzyme binds to its substrates, allowing them to more easily transform into products.

Enzyme Specificity

• Enzymes are highly specific, only catalyzing specific reactions.
• Specificity is due to the precise shape of the enzyme's active site and chemical properties.
• Example: Lactase only catalyzes the breakdown of lactose, not maltose.

Enzyme Naming

• Enzyme names typically end in "-ase".
• Often named after the substrate they bind or the reaction they catalyze, e.g., lactase, ATP synthase.

Conclusion

• Enzymes play a crucial role in catalyzing reactions within cells, with high specificity for their substrates.
• Watch further videos for details on Topics 2 and 3 in this unit.