AP Biology Unit 3: Cellular Energetics Review

Introduction

• Mrs. Jones from AP Bio Penguins
• "Penguins" symbolize students dressed for success.

Resources Available

• Daily reviews on Instagram: APBiopenguins
• 374-page review guide on Weebly: Includes topic questions, ICANN statements, multiple choice & free response questions with explanations.
• FRQ Friday: 4 free response questions posted weekly.
• 120 Quizzes games available on Weebly.

Lecture Agenda

• Focus topics:
  • Enzymes
  • Cellular respiration
  • Photosynthesis
• Practice questions: 2 multiple choice and 2 free responses.
• Open for questions during the lecture.

Free Energy

Gibbs Free Energy

• Defines energy available to do work.
• Reactions can either release (exergonic) or absorb (endergonic) energy.
• Equation:
  • ∆G = ∆H - T∆S
  • ∆G = change in Gibbs free energy

Endergonic vs. Exergonic Reactions

• Endergonic Reactions:
  • Energy must enter the system.
  • Positive ∆G; products have more energy than reactants.
  • Example: ADP + inorganic phosphate → ATP
• Exergonic Reactions:
  • Energy exits the system.
  • Negative ∆G; reactants have more energy than products.
  • Example: ATP → ADP + inorganic phosphate

Enzymes

• Biological catalysts that speed up reactions by lowering activation energy.
• Not consumed in reactions; can be used repeatedly.
• Factors affecting enzyme activity:
  • Temperature
  • pH
  • Salinity
• Types of Inhibitors:
  • Competitive Inhibitors: Compete for active site.
  • Non-competitive Inhibitors: Bind to allosteric site, changing enzyme shape.

Cellular Respiration

Overview

• Three main steps:
  • Glycolysis
  • Krebs Cycle
  • Oxidative Phosphorylation
• Focus on what goes in, what comes out, where it occurs, and why it's important.

Glycolysis

• Takes place in the cytosol.
• Inputs: Glucose (6 carbons)
• Outputs: 2 NADH, 2 pyruvates, 2 ATP

Krebs Cycle

• Takes place in the mitochondrial matrix.
• Starts with Acetyl-CoA.
• Outputs: 2 CO2, 3 NADH, 1 FADH2, 1 ATP (GTP).

Oxidative Phosphorylation

• Takes place in mitochondrial cristae.
• Produces ATP through chemiosmosis using the proton gradient.

Photosynthesis

Overview

• Two main steps:
  • Light Reactions
  • Calvin Cycle

Light Reactions

• Occur in the thylakoid membrane.
• Inputs: Water, light energy
• Outputs: ATP, NADPH, and oxygen.
• Linear vs. cyclic electron flow.

Calvin Cycle

• Occurs in the stroma.
• Inputs: 3 CO2, 9 ATP, 6 NADPH
• Outputs: G3P (3-carbon molecule).

Key Concepts

• Understand the importance of proton gradients in ATP production.
• Differentiate between different types of reactions (endergonic vs. exergonic).
• Recognize enzyme function and factors affecting it.

Practice Questions

• Multiple choice and free response practice questions available during the lecture.

Conclusion

• Daily reviews and resources available for ongoing support leading up to exams.
• Encourage questions throughout the lecture.