Lecture Notes: Unit 3 - Cellular Energetics

Introduction

• Lecture by Mrs. Jones from AP Bio Penguins
• Focus on Unit 3: Cellular Energetics
• AP Bio Penguins: Students dressed for success
• Resources available:
  • Daily review on Instagram (AP Bio Penguins)
  • Comprehensive review guide on Weebly
  • FRQ (Free Response Question) practice on Fridays
  • Quizzes and games on Weebly
  • Review PowerPoints available online

Lecture Plan

• Topics: Enzymes, Cellular Respiration, Photosynthesis
• Practice questions (multiple choice and free responses)

Free Energy and Reactions

• Gibbs Free Energy (ΔG): Energy available to do work
  • Enonic (Endergonic) reactions: Energy-absorbing
  • Exonic (Exergonic) reactions: Energy-releasing
• Formula: ΔG = ΔH - TΔS
  • ΔH: Change in enthalpy
  • ΔS: Change in entropy

Enzymes

• Function: Biological catalysts that speed up reactions by lowering activation energy
• Characteristics:
  • Proteins with specific structural levels (primary to quaternary)
  • Not consumed in reactions
  • Do not affect Gibbs free energy
• Mechanism:
  • Active site binds substrate, causing conformational change
  • Catalyze reactions, releasing products
• Inhibition:
  • Competitive Inhibitors: Compete with substrate for active site
  • Non-Competitive Inhibitors: Bind to allosteric site, altering enzyme shape

Cellular Respiration

• Three main stages: Glycolysis, Krebs Cycle, Oxidative Phosphorylation
• Glycolysis:
  • Occurs in cytosol
  • Converts glucose to 2 pyruvates, producing 2 ATP and 2 NADH
• Krebs Cycle (Citric Acid Cycle):
  • Occurs in mitochondrial matrix
  • Acetyl CoA enters cycle, producing CO2, NADH, FADH2, and 2 ATP per glucose
• Oxidative Phosphorylation:
  • Occurs in mitochondrial cristae
  • Electron Transport Chain creates a proton gradient
  • Chemiosmosis generates ATP via ATP synthase

Photosynthesis

• Two stages: Light Reactions and Calvin Cycle
• Light Reactions:
  • Occur in thylakoid membranes
  • Use light energy to produce ATP and NADPH
  • Involve Photosystem II and I, electron transport, and creation of a proton gradient
• Cyclic Electron Flow: Produces ATP without NADPH
• Calvin Cycle:
  • Occurs in stroma
  • Uses ATP and NADPH to convert CO2 to G3P (later forms glucose)

Key Concepts

• Differences between C3, C4, and CAM plants in photosynthesis
• Adaptations to environmental conditions

Practice Questions

• Multiple choice and free response questions covering respiration and photosynthesis concepts

Additional Resources

• Daily review sessions on Instagram (AP Bio Penguins)
• Interactive content on TikTok and YouTube

Conclusion

• Students encouraged to ask questions and use available resources to prepare for exams