Study Notes
Cell respiration is a process involving the oxidation and reduction of electron carriers to produce energy. It includes glycolysis, the link reaction, the Krebs cycle, and the electron transport chain.
- Oxidation — loss of electrons from a molecule. Example: NADH is oxidized to NAD+.
- Reduction — gain of electrons by a molecule. Example: FAD is reduced to FADH2.
- Phosphorylation — addition of a phosphate group to a molecule. Example: ATP donates a phosphate group to glucose.
- Glycolysis — splitting of glucose into pyruvate. Example: Glucose (6C) is converted to two pyruvate (3C) molecules.
- Link Reaction — conversion of pyruvate to acetyl CoA. Example: Pyruvate is decarboxylated and oxidized to form acetyl CoA.
- Krebs Cycle — series of reactions producing energy carriers. Example: Acetyl CoA is oxidized, producing NADH and FADH2.
- Electron Transport Chain — series of proteins transferring electrons. Example: Electrons from NADH and FADH2 are passed through the chain, creating a proton gradient.
- Chemiosmosis — diffusion of protons through ATP synthase to generate ATP. Example: H+ ions move through ATP synthase, synthesizing ATP.
Exam Tips
Key Definitions to Remember
- Oxidation
- Reduction
- Phosphorylation
- Glycolysis
- Link Reaction
- Krebs Cycle
- Electron Transport Chain
- Chemiosmosis
Common Confusions
- Confusing oxidation with reduction.
- Misunderstanding the role of oxygen in the electron transport chain.
Typical Exam Questions
- What is the role of NADH in cell respiration? NADH carries electrons to the electron transport chain.
- How does glycolysis contribute to ATP production? Glycolysis produces a net gain of 2 ATP molecules.
- Why is oxygen important in aerobic respiration? Oxygen acts as the final electron acceptor in the electron transport chain.
What Examiners Usually Test
- Understanding of the stages of cell respiration.
- Ability to explain the role of electron carriers.
- Knowledge of the adaptations of the mitochondrion for respiration.