31) The electrons excited by sunlight in photosystem I replaced : 1380763.
31) The electrons excited by sunlight in photosystem I are replaced by ________, and the electrons excited by sunlight in photosystem II are replaced by ________.
A) electrons from water; electrons from photosystem I
B) electrons from water; electrons from carbon dioxide
C) electrons from water; electrons from water
D) electrons from carbon dioxide; electrons from water
E) electrons from photosystem II; electrons from water
32) Electrons from photosystem I are transferred down an electron transport chain to ________, which become reduced to ________.
A) NAD+; NADPH
B) NADPH; NADP+
C) NADP+; NADPH
D) ADP; ATP
33) As a by-product of photosynthesis, what percentage of the Earth’s atmosphere is oxygen?
A) 31 percent
B) 41 percent
C) 21 percent
D) 10 percent
E) 50 percent
34) During the light reactions of photosynthesis:
A) H2O is oxidized to oxygen and hydrogen ions.
B) ATP is used to produce H2O.
C) ATP is used to produce NADPH.
D) CO2 is fixed into glucose.
35) Plants make ATP during the light reactions of photosynthesis. Why do plants also need to carry out the process of cellular respiration?
A) The ATP made during photosynthesis is different from the ATP made during cellular respiration.
B) The ATP made during photosynthesis is only enough to fuel the dark reactions. The plant has to carry out cellular respiration to make ATP for other metabolic activities.
C) Plants need to make ATP from cellular respiration only when the conditions for photosynthesis are bad.
D) Plants do not need to perform cellular respiration.
36) Where does the NADPH created during the light reactions accumulate?
A) in the stomata
B) in the thylakoid membrane
C) in the leaf’s epidermis
D) in the thylakoid compartment
E) in the stroma
37) During photosynthesis, energy is released and used to create ATP when:
A) electrons are passed down the energy hill during the light reactions.
B) electrons jump from a reaction center to a primary electron acceptor.
C) CO2 is fixed into sugars in the light reactions.
D) water is split, releasing oxygen.
E) electrons are passed from photosystem I to NADPH.
38) The electron carrier in photosynthesis that will donate electrons to CO2 so that it can be fixed into sugars is:
39) The Calvin cycle takes place in the:
40) The Calvin cycle requires all of the following except: