Energy & Enzymes
Enzymes accelerate chemical reactions by lowering this.
Activation energy barrier (Q47)
During aerobic cellular respiration, electrons flow from ___ to ___.
Carbohydrate to oxygen (Q26, answer c)
NADH delivers electrons to the mitochondrial ETC through which pathway?
Complex I → Complex III → Complex IV (Q54, answer c)
In photosynthesis, the oxygen gas released during the light reactions comes from this molecule.
Water / H₂O (Q45, answer b)
Where can ATP synthase be found in a photosynthetic plant cell?
Both the thylakoid membrane and the inner mitochondrial membrane (Q39, answer c)
Enzymes never alter this overall thermodynamic value of a reaction.
ΔG / change in free energy (Q47)
Which molecule has the greatest potential energy: glucose, pyruvate, ATP, NADH, or FADH₂?
Glucose (Q35, answer a)
FADH₂ delivers electrons to the mitochondrial ETC through which pathway?
Complex II → Complex III → Complex IV (Q54, answer c)
Plastoquinone and plastocyanin shuttle what between the photosystems?
Electrons (Q38, answer b)
If a plant synthesizes a 6-carbon sugar, how many turns of the Calvin cycle are needed?
6 turns (Q40, answer c)
ATP hydrolysis is spontaneous, so how can cells store ATP?
The activation energy is very high. (Q42, answer c)
Pyruvate dehydrogenase produces NADH, acetyl-CoA, CO₂, and not this molecule.
Q37, answer e: all except ATP
During mitochondrial electron transport, how many protons does Complex II pump?
0 protons (Q83, answer a)
The cytochrome b6f complex in the thylakoid membrane is homologous to which mitochondrial ETC complex?
Complex III (Q31, answer c)
If photosynthetic eukaryotic cells are given ¹⁴CO₂, where is the ¹⁴C label found first?
3-phosphoglycerate / 3-PGA (Q41, answer a)
Which type of enzyme inhibitor increases Km?
Competitive inhibitor (Q49, answer a)
Lactate fermentation recycles ___ from NADH.
NAD⁺ (Q32, answer b)
For two electrons moving through the mitochondrial ETC, Complex I, II, III, and IV pump how many H⁺?
4, 0, 4, and 2 (Q83, answer a)
For PSII/P680 to extract electrons from water, oxidized P680 must have a redox potential that is more ___ than water/O₂.
More positive (Q21, answer a)
True or false: glucose is the immediate product of carbon fixation by Rubisco.
False (Q78, answer b)
Which type of enzyme inhibitor decreases Vmax and cannot be outcompeted by adding more substrate?
Noncompetitive inhibitor (Q48/Q50, answer b)
True or false: fermentation requires oxygen
False (Q72, answer b)
If ATP synthase uses 4 H⁺ to make 1 ATP, how many ATP are generated per NADH AND per FADH₂?
2.5 ATP per NADH; 1.5 ATP per FADH₂ (Q85, answer c)
Per synthesis of one O₂ during the light reactions, how many total protons are delivered into the thylakoid lumen?
12 H⁺ total (Q45, answer b)
Under 24 hours of constant light, which plant type would be unable to reduce photorespiration because it requires darkness to absorb CO₂?
CAM plants are the only type of plant that absorbs HCO3 - only during nighttime hours. (Q34, answer c)