AP Bio Penguins - Unit 3 Cellular Energetics Review Session - Enzymes, Photosynthesis, Energy

Sep 29, 2026

AP Bio Penguins Unit 3 Cellular Energetics review session focuses on enzymes and the role of energy in life, covering how enzymes function as biological catalysts that lower activation energy without being consumed, and how concentration, temperature, pH, inhibitors, and denaturation affect activity. The review also explains endergonic versus exergonic reactions, energy coupling, and metabolic pathways. Photosynthesis is summarized from reactants and evolution to light reactions and the Calvin cycle, including cyclic versus linear electron flow.

LanguageEnglish

CategoryExam

FormatPDF

Pages37

Reading Time1 h 33 min

AccessFree to download

Unit 3 Cellular Energetics

Enzymes

Energy and Reaction Types

Photosynthesis

AP Bio Penguins are Dressed for Success Available Resources Daily Review on IG stories (started 2/2) 505-page Review Guide on Weebly Recorded FRQ Fridays on YouTube 120+ Wayground Games Review Videos/PowerPoints on Weebly [Weebly: www.apbiopenguins.weebly.com](Weebly: www.apbiopenguins.weebly.com) Unit 3 Cellular Energetics Enzymes Energy Photosynthesis Cellular Respiration Practice Questions Exam Format & Resources 12–16% Exam Weighing Functions: Enzymes * Biological catalyst * Speeds up chemical reactions * Reduces the activation energy Important Notes: * Enzymes are PROTEINS * Are NOT consumed by the reaction * Have no effect on the change in Gibbs Free Energy Unit 3 Cellular Energetics Functions: * Biological catalyst * Speeds up chemical reactions * Reduces the activation energy Enzymes Environmental Factors: * concentration of substrate/enzyme * chemical environment * inhibitors * temperature * pH Denaturation: Change to structure of a component inan enzymatic system may result in change in function or efficiency Temp/pH: Outside optional range causes changes to structure by disrupting H bonds Inhibitors: Important Notes: * Enzymes are PROTEINS * Are NOT consumed by the reaction * Have no effect on the change in Gibbs Free Energy Competitive * binds to the active site Noncompetitive * Binds to allosteric site Unit 3 Cellular Energetics Endergonic Reaction: Energy * Not spontaneous * ABSORB energy * Example: ADP + Pi → ATP Exergonic Reaction: * Spontaneous * RELEASE energy * Example: ATP → ADP + Pi Role of Energy in Life: * All living systems require energy input * Life requires highly ordered system without violation of first and second laws of thermos * Energy input > Energy loss * Energy coupling * Significant loss of order or energy flow results in death * Metabolic Pathways: * Core metabolic pathways evolutionarily conserved across all domains (Archaea, Bacteria, Eukarya)– Glycolysis & Ox Phos Unit 3 Cellular Energetics Photosynthesis series of reactions that use carbon dioxide (CO2 ), water (H2 O), and light energy to make carbohydrates and oxygen (O2 ) Evolution of Photosynthesis: * first evolved in prokaryotes * cyanobacteria photosynthesis responsible for oxygenated atmosphere * prokaryotic photosynthesis pathway was foundation for eukaryotic photosynthesis contains photosystems & electron transport chains site of carbon fixation rxns fluid w/i the inner membrane and outside the thylakoid thylakoid organized into stacks site of light reactions Unit 3 Cellular Energetics Photosynthesis series of reactions that use carbon dioxide (CO2 ), water (H2 O), and light energy to make carbohydrates and oxygen (O2 ) Light Reactions: * Location: Thylakoid Membrane/Grana * Starting Material: * Water (electrons) * Photons (energy) * Products: * ATP * NADPH Cyclic PS I ONLY Synthesizes ATP ONLY Electron Transport Chain Protons are pumped into thethylakoid space Linear PS I & PS II Synthesizes ATP & NADPH Unit 3 Cellular Energetics Photosynthesis series of reactions that use carbon dioxide (CO2 ), water (H2 O), and light energy to make carbohydrates and oxygen (O2 ) Calvin Cycle: * Location: Stroma * Starting Material: * 3 CO2 * 9 ATP * 6 NADPH * Products: * G3P Unit 3 Cellular Energetics

FAQs

What are the key functions of enzymes in cellular energetics?

Enzymes are biological catalysts that speed up chemical reactions by reducing activation energy. They are proteins, are not consumed in the reaction, and do not change the Gibbs Free Energy change.

How do environmental factors and inhibitors affect enzyme activity?

Enzyme activity depends on substrate/enzyme concentration, chemical environment, inhibitors, temperature, and pH. Temperature and pH outside the optional range disrupt structure via hydrogen bond disruption, and inhibitors affect enzyme function by binding either the active site (competitive) or an allosteric site (noncompetitive).

What are the main stages of photosynthesis covered in this review?

The review outlines overall photosynthesis as reactions using CO2, H2O, and light energy to produce carbohydrates and O2, then details light reactions in the thylakoid membrane/Grana and the Calvin cycle in the stroma. It also contrasts cyclic photosystem I only (ATP only) with linear electron flow (ATP and NADPH).

Sep 29, 2026

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