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7.E: Photosynthesis (Exercises)

Last updated

Jan 30, 2025
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- 7.4: Using Light Energy to Make Organic Molecules
- 8: Cell Division by Mitosis

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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 CO₂ 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 CO₂

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).

7.1: Overview of Photosynthesis

Multiple Choice

Free Response

7.2: Light-Dependent Reactions of Photosynthesis

Multiple Choice

Free Response

7.3: Using Light Energy to Make Organic Molecules

Multiple Choice

Free Response

Contributors and Attributions

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