7.E: Photosynthesis (Exercises)
7.1: Overview of Photosynthesis
Multiple Choice
What two products result from photosynthesis?
A. water and carbon dioxide
B. water and oxygen
C. glucose and oxygen
D. glucose and carbon dioxide
- Answer
-
C
Which statement about thylakoids in eukaryotes is not correct?
A. Thylakoids are assembled into stacks.
B. Thylakoids exist as a maze of folded membranes.
C. The space surrounding thylakoids is called stroma.
D. Thylakoids contain chlorophyll.
- Answer
-
B
From where does a heterotroph directly obtain its energy?
A. the sun
B. the sun and eating other organisms
C. eating other organisms
D. simple chemicals in the environment
- Answer
-
C
Free Response
What is the overall purpose of the light reactions in photosynthesis?
- Answer
-
To convert solar energy into chemical energy that cells can use to do work.
Why are carnivores, such as lions, dependent on photosynthesis to survive?
- Answer
-
Because lions eat animals that eat plants.
7.2: Light-Dependent Reactions of Photosynthesis
Multiple Choice
What is the energy of a photon first used to do in photosynthesis?
A. split a water molecule
B. energize an electron
C. produce ATP
D. synthesize glucose
- Answer
-
B
Which molecule absorbs the energy of a photon in photosynthesis?
A. ATP
B. glucose
C. chlorophyll
D. water
- Answer
-
C
Plants produce oxygen when they photosynthesize. Where does the oxygen come from?
A. splitting water molecules
B. ATP synthesis
C. the electron transport chain
D. chlorophyll
- Answer
-
A
Which color(s) of light does chlorophyll a reflect?
A. red and blue
B. green
C. red
D. blue
- Answer
-
B
Three of the same species of plant are each grown under a different colored light for the same amount of time. Plant A is grown under blue light, Plant B is grown under green light, and Plant C is grown under orange light. Assuming the plants use only chlorophyll a and chlorophyll b for photosynthesis, what would be the predicted order of the plants from most growth to least growth?
A. A, C, B
B. A, B, C
C. C, A, B
D. B, A, C
- Answer
-
A
Free Response
Describe the pathway of energy in light-dependent reactions.
- Answer
-
The energy is present initially as light. A photon of light hits chlorophyll, causing an electron to be energized. The free electron travels through the electron transport chain, and the energy of the electron is used to pump hydrogen ions into the thylakoid space, transferring the energy into the electrochemical gradient. The energy of the electrochemical gradient is used to power ATP synthase, and the energy is transferred into a bond in the ATP molecule. In addition, energy from another photon can be used to create a high-energy bond in the molecule NADPH.
7.3: Using Light Energy to Make Organic Molecules
Multiple Choice
Where in plant cells does the Calvin cycle take place?
A. thylakoid membrane
B. thylakoid space
C. stroma
D. granum
- Answer
-
C
Which statement correctly describes carbon fixation?
A. the conversion of CO
2
to an organic compound
B. the use of RuBisCO to form 3-PGA
C. the production of carbohydrate molecules from G3P
D. the formation of RuBP from G3P molecules
E. the use of ATP and NADPH to reduce CO
2
- Answer
-
A
Which order of molecular conversions is correct for the Calvin cycle?
A. RuBP + G3P→3-PGA→sugar
B. RuBisCO→CO2→RuBP→G3P
C. RuBP + CO2→[RuBisCO]3-PGA→G3P
D. CO2→3-PGA→RuBP→G3P
- Answer
-
C
What is the molecule that leaves the Calvin cycle to be converted into glucose?
A. ADP
B. G3P
C. RuBP
D. 3-PGA
- Answer
-
B
Free Response
Which part of the Calvin cycle would be affected if a cell could not produce the enzyme RuBisCO?
- Answer
-
None of the cycle could take place, because RuBisCO is essential in fixing carbon dioxide. Specifically, RuBisCO catalyzes the reaction between carbon dioxide and RuBP at the start of the cycle.
Explain the reciprocal nature of the net chemical reactions for photosynthesis and respiration.
- Answer
-
Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. The reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy. Thus, the reactants of photosynthesis are the products of respiration, and vice versa.
Contributors and Attributions
Remixed and/or curated from the following works:
Clark, M. A., Douglas, M., & Choi, J. (2018). 2.5.8 Review Questions and 2.5.9 Critical Thinking Questions . In Biology 2e . OpenStax (CC BY 4.0; Access for free at https://openstax.org/books/biology-2e/pages/1-introduction ).