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