49) Photosynthetic organisms derive their carbon from
A) carbon monoxide.
B) carbon dioxide.
C) hydrocarbons.
D) methane.
50) ATP and NADPH
A) power sugar synthesis during the Calvin cycle.
B) are products of the Calvin cycle.
C) provide energy to photosystem I and photosystem II.
D) are used in the electron transport chain to pump H+ into the thylakoid space.
51) To produce one glucose, the Calvin cycle needs to be run ________ times.
A) two
B) four
C) six
D) eight
52) The Calvin cycle constructs ________, an energy-rich molecule that a plant cell can then use
to make glucose or other organic molecules.
A) G3P
B) ATP
C) NADH
D) carbon dioxide
53) The addition of oxygen instead of carbon dioxide to RuBP results in
A) cellular respiration.
B) photorespiration.
C) photophosphorylation.
D) aerobic respiration.
54) Photorespiration
A) may be an evolutionary relic from when atmospheric O2 levels were low.
B) is of benefit to the plant since it breaks down rubisco.
C) is attributable to high CO2 levels.
D) produces glucose.
55) What is the main adaptive advantage of the C4 and CAM photosynthesis strategies over the
C3 strategy?
A) They help the plant synthesize glucose efficiently under dry conditions.
B) They allow the plant to fix carbon under conditions of low CO2.
C) They allow the plant to fix carbon in cool conditions.
D) They make it possible for the plant to use the Calvin cycle at night.
56) The ultimate source of all the food we eat and the oxygen we breathe is
A) cellular respiration.
B) photosynthesis.
C) glycolysis.
D) anaerobic metabolism.
57) Plants use sugars as
A) a fuel for photosynthesis.
B) a starting material for the Calvin cycle.
C) a source of electrons for chemiosmosis.
D) a fuel for cellular respiration and a starting material for making other organic molecules.
58) Plant cells
A) lack mitochondria and chloroplasts.
B) lack mitochondria but have chloroplasts.
C) have mitochondria but do not have chloroplasts.
D) have mitochondria and chloroplasts.
59) Global warming due to the greenhouse effect may be
A) moderated by photosynthesis, which removes carbon dioxide from the atmosphere.
B) made worse by photosynthesis, which adds carbon dioxide to the atmosphere.
C) reduced by the burning of fossil fuels, which removes oxygen from the atmosphere.
D) of little concern, since it is part of the normal cycle for the planet.
60) Which of the following statements about the greenhouse effect is true?
A) The greenhouse effect is reduced by deforestation.
B) The greenhouse effect is exacerbated by the use of fossil fuels.
C) The greenhouse effect will decrease the average temperature of the planet.
D) The greenhouse effect has no direct relationship with the Industrial Revolution of the 1800s.
61) It has been argued that cutting old-growth forests and replacing them with plantations of
young trees would help to alleviate the threat of global greenhouse warming. What important
fact does this argument ignore?
A) Forests play too minor a role in global CO2 dynamics, which are affected far more by marine
algae.
B) Young trees fix carbon at a lower rate per unit mass than old trees.
C) Most of the biomass of the cut trees would be added to the atmosphere as CO2 within a few
years.
D) Most of the young trees would die within a few years.
62) Ozone
A) formation is promoted by CFCs.
B) is broken down by carbon dioxide.
C) is a source of oxygen for cellular respiration.
D) protects Earth from ultraviolet radiation.
63) Ozone consists of ________ oxygen atom(s).
A) one
B) two
C) three
D) four
64) Which of the following has been a major source of ozone destruction over the past 50 years?
A) chlorofluorocarbons (CFCs)
B) ethylene glycol (C2H6O2)
C) carbon dioxide (CO2)
D) methane (CH4)
65) Chlorophyll is located in ________, which are found in ________, which are concentrated in
________.
A) thylakoids; chloroplasts; mesophyll
B) chloroplasts; thylakoids; mesophyll
C) mesophyll; chloroplasts; thylakoids
D) mesophyll; thylakoids; chloroplasts
66) You want to use radioactively labeled oxygen to trace carbon fixation in a plant. You should
incorporate the radioactively labeled oxygen into
A) O2.
B) CO2.
C) H2O.
D) C6H12O6.
67) Put the following steps of the light reactions in the correct order:
1. Light excites an electron from photosystem I.
2. Light excites an electron from photosystem II.
3. Electrons reduce NADP+ to NADPH.
4. Electrons pass through an electron transport chain, which generates a H+ gradient used to
make ATP.
A) 1, 2, 3, 4
B) 1, 4, 2, 3
C) 2, 4, 1, 3
D) 2, 3, 1, 4
68) Put the following steps of the Calvin cycle in the correct order:
1. Carbon fixation
2. Regeneration of RuBP
3. Release of G3P
4. Reduction
A) 1, 2, 3, 4
B) 1, 3, 4, 2
C) 1, 4, 3, 2
D) 4, 1, 2, 3
69) Purple sulfur bacteria are organisms capable of photosynthesis. They get their name, in part,
because they use H2S (hydrogen sulfide) instead of water during the light reactions. In what
form would you expect to find sulfur (S) as a result of photosynthesis in these bacteria?
A) S2
B) SO2
C) CS2
D) C6H12S6
70) Many of the regions of the world where hunger is prevalent are also regions with hot and dry
climates. What types of agricultural crops would you suggest that these regions attempt to grow?
A) C3 plants, such as wheat and rice
B) C3 plants and C4 plants, such as corn and sugarcane
C) C3 plants and CAM plants, such as prickly pear and pineapple
D) C4 plants and CAM plants
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71) Atrazine is a widely used herbicide that binds to a protein in photosystem II, ultimately
causing a breakdown in electron transport. Atrazine would first inhibit the production of
A) NADPH.
B) G3P.
C) ATP.
D) O2.
72) Red algae are found in relatively deep water. In order for light to penetrate to these depths, it
must be high in energy. Which wavelengths of light would you expect red algae to use?
A) red
B) yellow
C) green
D) blue
73) Which of the following is not an expected outcome of global climate change?
A) extreme weather patterns
B) lower sea levels
C) spread of tropical diseases
D) increased extinction rates
74) It has been suggested that global warming could be halted by fertilizing the oceans to
increase the growth of algae. How might this affect the greenhouse effect?
A) Algal photosynthesis would use up more CO2, which traps heat.
B) Algal photosynthesis would produce more O2, which blocks light.
C) Algal photosynthesis would be inhibited by the addition of fertilizer.
D) Algae photosynthesis would use heat in place of photons.
7.2 Art Questions
1) In this drawing of a chloroplast, which structure represents the thylakoid membrane?
A) structure A
B) structure B
C) structure C
D) structure D
2) According to this figure, how do hydrogen ions make their way from the stroma to the
thylakoid interior?
A) through photosystem I
B) through an electron transport chain molecule
C) through the ATP synthase
D) directly through the phospholipids of the thylakoid membrane
After reading the paragraph below, answer the questions that follow.
The graph below shows records of temperature (light gray line) and CO2 (dark gray line) over
the past 1,000 years. CO2 is recorded in parts per million (ppm).
3) If you focus on the data from the mid-1900s (indicated by the arrow) through today, the graph
shows that
A) there is a correlation between CO2 and temperature; when CO2 levels are high, so is
temperature.
B) there is a correlation between CO2 and temperature; when CO2 levels are high, temperature is
low.
C) there is no correlation between CO2 and temperature; CO2 fluctuates randomly and
temperature is constant.
D) there is no correlation between CO2 and temperature; CO2 is constant and temperature
fluctuates randomly.
4) Currently, atmospheric CO2 levels are approximately 400 ppm. The annual mean growth rate
in CO2 is about 2 ppm/year. Assuming this trend continues, what would you predict the CO2
level to be in 100 years?
A) 100 ppm
B) 200 ppm
C) 600 ppm
D) 1,000 ppm
5) If the trends shown in the graph continue, how might this affect photosynthesis?
A) Photorespiration may increase, leading to an increase in photosynthetic production of sugar.
B) Photorespiration may increase, leading to a decrease in photosynthetic production of sugar.
C) C4 and CAM plants would be unable to photosynthesize.
D) There would be no effect on photosynthesis, since CO2 and temperature are stable.
7.3 Scenario Questions
After reading the paragraph below, answer the questions that follow.
You’re conducting an experiment to determine the effect of different wavelengths of light on the
absorption of carbon dioxide as an indicator of the rate of photosynthesis in aquatic ecosystems.
If the rate of photosynthesis increases, the amount of carbon dioxide in the environment will
decrease, and vice versa.
Small aquatic plants are placed into three containers of water mixed with carbon dioxide.
Container A is placed under normal sunlight, B under green light, and C under red light. The
containers are observed for a 24-hour period.
1) Based on your knowledge of the process of photosynthesis, the plant in the container placed
under red light would probably
A) absorb no CO2.
B) absorb the same amount of CO2 as the plants under the green light.
C) absorb less CO2 than the plants under the green light.
D) absorb more CO2 than the plants under the green light.
2) Carbon dioxide absorption is an appropriate indicator of photosynthesis because
A) CO2 is needed to produce sugars in the Calvin cycle.
B) CO2 is needed to complete the light reactions.
C) plants produce oxygen gas by splitting CO2.
D) the energy in CO2 is used to produce ATP and NADPH.