Complete this summary map of photosynthesis.

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In photosynthesis, _________ is oxidized and _________ is reduced.

a. Water . . . Oxygen

b. Carbon dioxide . . . Water

c. Water . . . Carbon dioxide

d. Glucose . . . Carbon dioxide

Which of the following are produced by reactions that take place in the thylakoids and consumed by reactions in the stroma?

a. CO₂ and H₂O

b. ATP and NADPH

c. ATP, NADPH, and CO₂

d. ATP, NADPH, and O₂

When light strikes chlorophyll molecules in the reaction-center complex, they lose electrons, which are ultimately replaced by

a. Splitting water

b. Oxidizing NADPH

c. The primary electron acceptor

d. The electron transport chain

The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why? (Explain your answer.)

a. It is often too cold at night for these reactions to take place.

b. Carbon dioxide concentrations decrease at night.

c. The Calvin cycle depends on products of the light reactions.

d. Plants usually close their stomata at night.

Which of the following does not occur during the Calvin cycle?

a. Carbon fixation

b. Oxidation of NADPH

c. Consumption of ATP

d. Release of oxygen

Why is it difficult for C3 plants to carry out photosynthesis in very hot, dry environments such as deserts?

a. The light is too intense and destroys the pigment molecules.

b. The closing of stomata keeps CO₂ from entering and O₂ from leaving the plant.

c. They must rely on photorespiration to make ATP.

d. CO₂ builds up in the leaves, blocking carbon fixation.

How is photosynthesis similar in C4 plants and CAM plants?

a. In both cases, the light reactions and the Calvin cycle are separated in both time and location.

b. Both types of plants make sugar without the Calvin cycle.

c. In both cases, rubisco is not used to fix carbon initially.

d. Both types of plants make most of their sugar in the dark.

To synthesize one glucose molecule, the Calvin cycle uses _________ molecules of CO₂, _________ molecules of ATP, and _________ molecules of NADPH.

Compare and describe the roles of CO₂ and H₂O in cellular respiration and photosynthesis.

The following diagram compares the chemiosmotic synthesis of ATP in mitochondria and chloroplasts. Identify the components that are shared by both organelles and indicate which side of the membrane has the higher H+ concentration. Then label on the right the locations within the chloroplast.

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Continue your comparison of electron transport and chemiosmosis in mitochondria and chloroplasts. In each case:

a. Where do the electrons come from?

b. How do the electrons get their high potential energy?

c. What picks up the electrons at the end of the chain?

d. How is the energy released as electrons are transferred down the electron transport chain used?

Most scientific experts agree that climate change is already occurring and has potentially catastrophic consequences for all of life on Earth. The Paris Agreement of 2015 represented a global consensus on the need to reduce greenhouse gas emissions. However, in 2017 the United States announced its intention to withdraw from the Agreement in 2020. Go online to research and summarize the main agreements reached in this historic global climate accord and the U.S. government's reasons for withdrawing. What roles do you think scientists, politicians, and citizens will need to play to cut emissions and limit global warming?