What is the net ATP yield from glycolysis per glucose molecule?

• 2 ATP

• 4 ATP

• 36 ATP

• 38 ATP

What is the main purpose of the electron transport chain?

• To break down glucose into pyruvate

• To produce ATP through oxidative phosphorylation

• To fix carbon dioxide during photosynthesis

• To store energy as NADPH

Under anaerobic conditions, what do plant cells produce instead of entering the Krebs cycle?

• Lactic acid

• Ethanol and CO₂

• Citric acid

• Glucose

Which factor does NOT directly increase the rate of respiration in plants?

• High temperature

• Light (except for photorespiration)

What happens when ATP levels are high in a cell?

• Respiration increases to produce more ATP

• Respiration slows due to feedback inhibition

• Glycolysis stops completely

• Fermentation begins

Which of the following is true about photorespiration?

• It occurs only in the dark

• It is enhanced by high light intensity

• It produces more ATP than aerobic respiration

• It does not involve oxygen

Why is aerobic respiration more efficient than anaerobic respiration?

• It produces ethanol instead of lactic acid

• It yields 36 ATP per glucose compared to 2 ATP

• It does not require oxygen

• It occurs only in photosynthetic tissues

How many ATP molecules are produced directly (via substrate-level phosphorylation) in glycolysis and the Krebs cycle combined?

• 2 ATP

• 4 ATP

• 6 ATP

• 10 ATP

Glycolysis: 2 ATP (from 1,3-bisphosphoglycerate & phosphoenolpyruvate). Krebs cycle: 2 ATP (from GTP → ATP). Total direct ATP = ?

• 2 ATP

• 4 ATP

• 6 ATP

• 8 ATP

If oxygen is unavailable, what is the net ATP yield from fermentation of one glucose molecule?

• 2 ATP

• 4 ATP

• 6 ATP

• 0 ATP