ATI TEAS (Test of Essential Academic Skills) Version 7ReadingHard
A student is reading a textbook chapter on cellular respiration. The text describes the process as starting with glycolysis in the cytoplasm, followed by the Krebs cycle in the mitochondrial matrix, and concluding with oxidative phosphorylation on the inner mitochondrial membrane. The chapter then discusses how abnormalities in the electron transport chain can lead to various metabolic disorders. Based on this, which component of cellular respiration is directly responsible for generating the majority of ATP?
- AGlycolysis
- BKrebs cycle
- COxidative phosphorylation
- DMitochondrial matrix
Show answer & explanationAnswer & explanation
Correct answer: C. Oxidative phosphorylation
The text explicitly states that cellular respiration 'concluding with oxidative phosphorylation' and then discusses how 'abnormalities in the electron transport chain' (a key part of oxidative phosphorylation) lead to metabolic disorders, implying its critical role in energy generation. Oxidative phosphorylation generates the vast majority of ATP.
Why the other options are wrong
- A. Glycolysis produces a small net amount of ATP (2 ATP) and pyruvate.
- B. The Krebs cycle produces ATP (2 ATP), but primarily generates electron carriers (NADH and FADH2) for the final stage.
- D. The mitochondrial matrix is a location, not a process that generates ATP directly.
ATP Production in Cellular Respiration
Cellular respiration is a metabolic pathway that breaks down glucose to produce ATP. The majority of ATP is generated during the final stage, oxidative phosphorylation, which occurs on the inner mitochondrial membrane and involves the electron transport chain.
- Glycolysis, Krebs cycle, and oxidative phosphorylation are the main stages.
- Glycolysis produces a small amount of ATP.
- Krebs cycle produces electron carriers (NADH, FADH2).
- Oxidative phosphorylation uses these carriers to generate most ATP.
Memory trick: Glyco small, Krebs just drives, Ox-Phos makes the ATP thrive.