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31

Biology

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31. The energy to hydrolyze water comes from
a. oxidized chlorophyll.
b. reduced chlorophyll.
c. the proton gradient.
d. ATP.
e. NADPH + H+.

32. Photosynthesis is the process that uses light energy to extract hydrogen atoms from
a. glucose.
b. chlorophyll.
c. CO2.
d. water.
e. None of the above

33. The Z scheme is
a. the characteristic path of electrons when they are bounced out of the pigments of the reaction center.
b. another name for the splitting of water.
c. the addition of CO2 to RuBP to form a six-carbon sugar.
d. the passing of high-energy electrons through ATP synthase.
e. the wavelengths of light absorbed by a specific molecule.

34. The light energy absorbed by the P680 reaction center
a. oxidizes water.
b. removes a phosphate from ATP to form ADP.
c. fixes CO2 to form sugars.
d. is used to form rubisco.
e. is reflected and causes plants to appear green.

35. In cyclic photophosphorylation, chlorophyll is reduced by
a. NADPH.
b. a chemiosmotic mechanism.
c. plastoquinone.
d. ATP.
e. hydrogen ions liberated by the splitting of a water molecule.

36. Free energy is released in cyclic photophosphorylation
a. by the formation of ATP.
b. during the excitation of chlorophyll.
c. during the fluorescence of chlorophyll.
d. during each of the redox reactions of the electron transport chain.
e. when electrons are transferred from photosystem I to photosystem II.

37. In noncyclic photophosphorylation, the chlorophyll in photosystem I returns to its reduced state by
a. water.
b. accepting electrons from the transport chain of photosystem II.
c. two photons of light.
d. NADPH.
e. ATP.

38. The Calvin-Benson cycle uses more ATP than NADPH + H+. The needed ATP comes from
a. the splitting of water.
b. the reduction of oxygen.
c. the oxidation of glucose.
d. cyclic P700.
e. noncyclic electronic transport.

39. Cyclic electron transport
a. occurs when the ratio of NADPH + H+ to NADP+ in the chloroplasts of some organisms is high.
b. is a series of redox reactions.
c. stores its released energy as a proton gradient.
d. is completed when the electron returns to P700+.
e. All of the above

40. During cyclic photophosphorylation, the energy to produce ATP is provided by
a. heat.
b. NADPH.
c. ground-state chlorophyll.
d. the redox reactions of the electron transport chain.
e. the Calvin-Benson cycle.