3.5 Cellular Respiration

What else do you need to know about Cellular Respiration?

The concept of chemiosmosis, the establishment of a proton gradient, and the role of ATP synthase in oxidative phosphorylation are required. You should also understand that decoupling oxidative phosphorylation from electron transport generates heat, which can be used by endothermic organisms to regulate body temperature. Crucially, the AP Exam explicitly excludes the memorization of specific steps in glycolysis and the Krebs cycle, the structures of the molecules, the names of the enzymes involved, and the full names of specific electron carriers in the ETC.

Can you do these?

• I can state that cellular respiration and fermentation use energy from biological macromolecules to synthesize ATP and are characteristic of all forms of life.
• I can describe how aerobic cellular respiration involves a series of coordinated enzyme-catalyzed reactions that capture energy.
• I can explain how the electron transport chain establishes an electrochemical gradient, how chemiosmosis drives ATP formation, and how decoupling generates heat.
• I can describe glycolysis as a pathway that releases energy from glucose to form ATP, NADH, and pyruvate.
• I can explain the transport of pyruvate to the mitochondrion and its oxidation during the Krebs cycle to release CO2, NADH, and FADH2.
• I can describe the Krebs cycle's role in releasing carbon dioxide, synthesizing ATP, and transferring electrons to coenzymes.
• I can trace the transfer of electrons from glycolysis and the Krebs cycle to the ETC via NADH and FADH2.
• I can explain how electron transfer through the ETC establishes a proton gradient across the inner mitochondrial membrane.
• I can describe how fermentation allows glycolysis to continue in the absence of oxygen by producing organic molecules such as alcohol or lactic acid.

How is Cellular Respiration tested on the exam?

This topic is heavily tied to the suggested skill of Representing and Describing Data (Skill 4.A). You may be assessed on your ability to construct graphs to represent cellular respiration data (e.g., from a yeast fermentation lab measuring CO2 production). This includes selecting the appropriate type of graph (bar, line, scatter, etc.), correctly labeling axes with units, scaling, accurately plotting data with error bars, and drawing trend lines where appropriate. Questions may also test the conceptual understanding of energy transfer and the consequences of disrupting the electrochemical gradient.