Mitochondrion
What is the function of the mitochondrial cristae?
To increase surface area for the electron transport chain and ATP synthesis.
What is the role of the thylakoid membrane?
Site of light-dependent reactions and electron transport chain.
Where does glycolysis occur and what is its net ATP yield?
Cytoplasm; net gain of 2 ATP.
What is the role of RuBisCO in carbon fixation?
It catalyzes the fixation of CO₂ to RuBP in the Calvin cycle.
How are ATP synthase mechanisms similar in chloroplasts and mitochondria?
Both use chemiosmosis and proton gradients.
Why is the inner mitochondrial membrane impermeable to ions?
To maintain the proton gradient necessary for chemiosmosis.
Why are chlorophyll molecules organized into photosystems?
To maximize light absorption and efficient energy transfer.
What is the link reaction and where does it occur?
Conversion/Oxidation of pyruvate to acetyl-CoA in the mitochondrial matrix.
A plant is exposed to high light intensity but low CO₂ levels. Predict the effect on the Calvin cycle.
The Calvin cycle slows down due to insufficient CO₂ for carbon fixation.
Why is photosynthesis considered endergonic and respiration exergonic?
Photosynthesis requires energy input; respiration releases energy.
Explain how the structure of the mitochondrial matrix supports its function.
It contains enzymes for the link reaction and Krebs cycle, along with mitochondrial DNA and ribosomes.
Explain how the structure of grana enhances photosynthesis.
Stacked thylakoids increase surface area for light absorption.
Why is oxygen essential for aerobic respiration?
It acts as the final electron acceptor in the electron transport chain.
Explain why water is essential for the light-dependent reactions beyond being a source of electrons.
It also provides protons for the gradient and releases oxygen as a byproduct.
Compare the location of ETC in chloroplasts vs mitochondria.
Thylakoid membrane vs inner mitochondrial membrane (cristae).
Predict the effect of damage to the inner membrane on ATP production.
ATP production would decrease because the proton gradient and ETC would be disrupted.
Predict what happens if the thylakoid membrane becomes leaky to protons.
ATP production decreases due to loss of proton gradient.
A student adds an inhibitor that blocks ATP synthase but leaves the electron transport chain intact. Predict the immediate effects on proton gradient and oxygen consumption.
Blocking ATP synthase prevents protons from flowing back into the matrix, so the proton gradient rapidly becomes very steep. As this gradient builds up, it creates resistance to further proton pumping, which slows down electron transport. As a result, oxygen consumption decreases because fewer electrons reach oxygen at the end of the chain.
Explain how proton gradients are generated in the thylakoid membrane.
Through photolysis of water, electron transport chain activity, and proton pumping into the thylakoid lumen.
How would climate change affect global photosynthesis rates?
Changes in temperature, CO₂, and water availability alter rates.
Evaluate the evidence supporting the endosymbiotic theory for mitochondria.
Presence of circular DNA, 70S ribosomes, double membrane, and independent replication.
Compare the roles of Photosystem I and Photosystem II.
PSII splits water and generates electrons; PSI produces NADPH.
Mitochondria are supplied with excess NADH but limited ADP. Predict the effect on the rate of oxidative phosphorylation and explain why.
The rate decreases because ADP is required for ATP synthesis; without it, the proton gradient builds up and inhibits electron transport.
Predict the effect on G3P production if NADPH supply is reduced but ATP is still available.
G3P production decreases because NADPH is required for reduction in the Calvin cycle.
Evaluate the role of photosynthesis in the global carbon cycle.
It removes CO₂ from atmosphere and stores it in biomass.