AP Biology - Unit 3, Section 5: Compartmentalization

Introduction

• Focus of this section: Compartmentalization
• Ties back to the previous unit on cells

Metabolic Pathways

• Defined as a series of linked reactions
• Example:
  • A changes to B by enzyme 1
  • B changes to C by enzyme 2, etc.
• The product of one reaction is the substrate of the next
• Can form cycles (circular patterns in diagrams)
  • Note: Metabolites do not literally move in circles in cells

Compartmentalization

• Division of a larger object into smaller sections for specific functions
• Example: House with specific rooms (kitchen, bedroom, etc.)
  • Each room serves a specific purpose to enhance efficiency
• In cells: Organelles
  • Membrane-bound organelles in eukaryotic cells
  • Specialized functions enhance cellular efficiency
  • Prokaryotes lack membrane-bound organelles but still have specialized regions

Efficiency in Cells

• Compartmentalization optimizes efficiency
  • Organelles have all necessary enzymes and proteins for their functions
• Feedback Inhibition
  • Product at the end of a pathway inhibits an earlier step
  • Regulates production to prevent excess waste
  • Example: Product D inhibits enzyme 1

Metabolic Pathway Diseases

• Issues arise when an enzyme in the pathway malfunctions
• Causes:
  • Gene mutations, protein folding errors, etc.
• Effects:
  • Overproduction of one metabolite, underproduction of another
  • Example: Excess of E, deficiency of G

Conclusion

• Emphasis on the importance of compartmentalization in cells
• Fun reference: Drake meme about cells enjoying compartmentalization