MCB 259: PLANT PHYSIOLOGY 1998, Quiz 7 - November 11
Name (please print):



Why is the dark reaction called the dark reaction?
a) The dark reaction is an alternative to the light reaction that occurs during the night.
b) The dark reaction does not directly involve light.
c) The dark reaction is an adaptation that is found in shade plants.


What are the names for the **two** types of thylacoids in chloroplasts of higher plants?
Circle the two correct terms:
envelope thylacoid, grana thylacoid, stroma thylacoid, stoma thylacoid


Which molecules are used as light harvesting pigments in algae and/or higher plants?
*************** (More than one correct answer!) **************
Anthocyanins, Chlorophyll b, Phycobillins, Phytochroms, Carotenoids, Phycoerythrin, Chlorophyll a, Leghemoglobin


Which pigment in PSII is the one that in the reaction centers after light absorption actually passes the 'excited' electron to the next component (i.e. Phaeophytin) of the redox chain?
A) Chlorophyll a, B) Chlorophyll b, C) Phycobillin, D) Carotenoids


Is the reactioncenter pigment in PSI the same type as in PSII?
Yes No


How is ATP synthesis coupled to the photon driven redox chain of photosynthesis?
a) the complex undergoes a conformation change whose energy is used for ATP synthesis.
b) the electrochemical gradient for protons across the thylacoid membrane acts as an energy rich intermediate.
c) ATP is synthesized in the mitochondria and imported into the chloroplasts (in exchange for NADPH2.
d) an energy rich phosphorylated intermediate is produced during the "down hill" flow of electrons.


High concentrations of PQH2 activate a kinase that phosphorylates LHCII. This leads to
a) moving of the LHCII into the grana thylacoids and delivering photons to PSI
b) moving of the LHCII into the stroma thylacoids and delivering photons to PSII
c) stacking of stroma thylacoids to form grana thylacoids


Which is the central ion in Chlorophyll? A) Mg2+, B) Fe2+, C)Mn2+, D)Ca2+


Ions of which metal are part of the water splitting complex?
A) Magnesium, B) Manganese, C) Iron, D) Copper


During photosynthesis the inside of the thylacoids becomes
A) more acidic B) less acidic C) remains at the same pH as the stroma


Which of the following reactions (more than one!) contributes to the transport of protons through the thylacoid membrane:
photolysis of water,
the transport of the electrons from the reaction center chlorophyll to Phaeophytin,
the reduction of Plastoquinones,
the Plastoquinone cycle,
the oxidation of the plastoquinones at the cytochrome bf complex,
the reduction of Plastcyanin at the complex
the oxidation of the Plastocyanin at Photosystem I?
the reduction of NADP to NADPH+H+


The Emerson enhancement suggests that two photosystems work in series in oxygen releasing photosynthesis. These experiments showed
a) that the light harvesting complex II can serve both photosystems (PSI and PSII)
b) that light with wavelengths between 680nm and 700 nm can only be used for photosynthesis, if it is given together with light of wavelengths shorter than 680nm
c) that light absorbed by the cytochrome bf complex inhibits photosynthesis only if this complex is reduced

Some bacteria use H2S instead of water for photosynthesis. This suggests that
A) H2O/O2 and H2S/S have similar redox potentials
B) the O2 released during oxygen releasing photosynthesis originates from H2O
C) the O2 released during oxygen releasing photosynthesis originates from CO2.

Describe an experiment that suggests that each water splitting complex serves only a single Photosystem II complex: