Respiration Flashcards
Where in the cell does the link reaction occur?
In the mitochondrial matrix.
What is the role of oxygen in aerobic respiration?
Oxygen acts as the final electron acceptor in the electron transport chain, combining with electrons and protons to form water.
What is substrate-level phosphorylation, and in which stages of respiration does it occur?
Substrate-level phosphorylation is the direct synthesis of ATP from ADP and a phosphorylated intermediate. It occurs in glycolysis and the Krebs cycle.
Explain why respiration decreases at high temperatures.
High temperatures denature enzymes involved in respiration, such as those in glycolysis and the Krebs cycle, reducing the rate of reactions.
Explain the effect on ATP production if an inhibitor prevents the reduction of NAD+ to NADH in glycolysis.
Glycolysis would stop, as NAD+ is required to accept electrons. This would halt ATP production via substrate-level phosphorylation in glycolysis.
Explain why oxygen consumption increases after exercise.
Increased oxygen consumption supports higher ATP production during oxidative phosphorylation, as more energy is required to meet the demands of muscle contraction.
Explain the observation of decreased CO₂ production after adding an inhibitor of the electron transport chain.
The inhibitor prevents the regeneration of NAD+ and FAD from NADH and FADH₂, halting the Krebs cycle, which produces CO₂.
Describe the stages of glycolysis and the net products formed.
- Glucose is phosphorylated using ATP to form glucose-6-phosphate.
- It is then converted to fructose-1,6-bisphosphate.
- Fructose-1,6-bisphosphate splits into two 3-carbon molecules (glyceraldehyde-3-phosphate).
- These are oxidized to form 2 pyruvate molecules, producing 2 ATP (net gain) and 2 NADH.
Explain how the electron transport chain produces ATP.
Electrons from NADH and FADH₂ pass through the electron transport chain in the inner mitochondrial membrane.
Their energy is used to pump protons into the intermembrane space, creating a proton gradient.
Protons diffuse back into the mitochondrial matrix through ATP synthase, driving ATP production (chemiosmosis).
Oxygen acts as the final electron acceptor, forming water.
Compare and contrast aerobic respiration and photosynthesis.
Both involve electron transport chains and ATP synthesis via chemiosmosis.
Respiration is catabolic, breaking down glucose to release energy, whereas photosynthesis is anabolic, synthesizing glucose.
Oxygen is consumed in respiration and produced in photosynthesis.
Explain why anaerobic respiration produces less ATP than aerobic respiration.
Anaerobic respiration only includes glycolysis, which produces 2 ATP per glucose molecule. Aerobic respiration uses the Krebs cycle and oxidative phosphorylation, generating around 38 ATP.
