Ch. 8 Learning Curve
For every six CO2 molecules incorporated into carbohydrate molecules, how many triose phosphates can be exported from the chloroplast? -1 -10 -12 -6 -2
-2
Which of the following is needed directly to produce both triose phosphates and RuBP in the Calvin cycle? -ATP -NADPH -rubisco -O2 -photosystem II
-ATP
Which of these are products of the light-dependent reactions of photosynthesis that are required by reactions in the Calvin cycle? -ATP and NADPH -ATP and O2 -NADP+ and O2 -H2O and NADPH
-ATP and NADPH
T or F: The Calvin cycle is a relatively constant process, the rate of which is independent of factors such as temperature and nitrogen concentration.
-False
Photosystem II and photosystem I differ in: -plants and algae. that the reactions of photosystem II occur in the Calvin cycle, whereas the reactions of photosystem I occur outside of the Calvin cycle. -that photosystem I requires sunlight, whereas photosystem II is a dark reaction. -that photosystem I is located in the thylakoid, whereas photosystem II is in the stroma. -H+ production and electron donors and acceptors.
-H+ production and electron donors and acceptors
In plants and algae, ____ is the source of the electrons needed for photosynthesis. -H+ -NADPH -O2 -CO2 -H2O
-H2O
Which compound is required for the carboxylation step of the Calvin cycle? -3-PGA -ATP and NADPH -ATP -NADPH -RuBP
-RuBP
The Calvin cycle includes 15 enzymes, most of which are involved in: -starch synthesis. -reduction. -RuBP carboxylation. -ATP synthesis. -RuBP regeneration.
-RuBP regeneration
The regeneration of RuBP typically limits the rate of photosynthesis under low light intensities. This is because: -RuBP regeneration requires ATP. -RuBP regeneration requires ADP. -RuBP regeneration is part of the "dark reactions." -photosynthesis occurs only in high light. -None of these answer choices is correct.
-RuBP regeneration requires ATP
Which of the following is true when comparing the Calvin cycle and light-harvesting reactions of photosynthesis? -None of the other answer options is correct. -They take place in different types of cells in the plant. -They take place in different organelles. -They take place in different compartments of the same organelle.
-They take place in different compartments of the same organelle
Xanthophyll pigments: -reflect yellow light. -absorb light energy. -convert light energy into heat. -All of these choices are correct. -prevent formation of reactive oxygen species.
-all of these choices are correct
The organisms believed to be the first to use two different photosystems in a single photosynthetic electron transport chain are the: -green plants. -yeast. -algae. -archaea. -cyanobacteria.
-cyanobacteria
Which of these is responsible for the transport of electrons between photosystem II and photosystem I? -cytochrome b6f -chlorophyll -H2O -NADPH -NADP+
-cytochrome b6f
The process in which one cell takes up residence in another cell is called: -exocytosis. -endocytosis. -endosymbiosis. -commensalism. -parasitism.
-endosymbiosis
From where does the oxygen come that is produced as a by-product of photosynthesis? -from the breakdown of water -from the breakdown of carbohydrates -from the Calvin cycle -from the reduction of CO2
-from the breakdown of water
ATP production in photosynthesis requires: -light, electrons, and protons. -light and protons only. -light only. -electrons only. -protons only.
-light, electrons, and protons
Reactive oxygen species are detoxified in order to: -minimize damage to membranes. -recover electrons. -enhance linear electron transport. -enhance cyclic electron transport. -All of these choices are correct.
-minimize damage to membranes
From its ground state, photosystem II can: -pass electrons to photosystem I. -emit light energy. -pull electrons from H2O. -absorb light energy. -pull protons from H2O.
-pass electrons to photosystem I
The occurrence of photorespiration _____ CO2 and _____ ATP. -reduces; produces -produces; produces -consumes; consumes -oxidizes; produces -produces; consumes
-produces; consumes
Which step of the Calvin cycle would be affected first by a lack of NADPH? -All of these choices are correct. -regeneration -carboxylation -reduction
-reduction
Rubisco is characterized by: -the ability to use three substrates and faster catalysis. -fast catalysis. -slow catalysis and the ability to use two substrates. -the ability to use three substrates.
-slow catalysis and the ability to use two substrates
Photorespiration occurs because: -there is more O2 than CO2 in the atmosphere. -there is more O2 than CO2 and rubisco is a selective catalyst. -there is more O2 than CO2 and rubisco is a slow catalyst. -rubisco is a slow catalyst. -rubisco is a selective catalyst.
-there is more O2 than CO2 in the atmosphere
Photosystem I is a _____ than photosystem II. -weaker reductant -stronger oxidant and a stronger reductant -weaker oxidant and weaker reductant -weaker oxidant and a stronger reductant -stronger oxidant
-weaker oxidant and a stronger reductant
T or F: All photosynthetic bacteria possess two functionally distinct photosystems.
False