Question 1

Which of the following statements best explains why plants produce oxygen during photosynthesis?

Accepted Answer

Oxygen is a byproduct of the splitting of water molecules during the light reactions.

Question 2

A scientist uses water labeled with the heavy isotope $$^{18}O to $$water a plant. After photosynthesis, where would the $$^{18}O$$ label most likely be found?

Accepted Answer

In the oxygen gas ($$O_2) $$released by the plant.

Question 3

Which of the following equations correctly summarizes the overall process of photosynthesis?

Accepted Answer

$$6CO_2 + 12H_2O \rightarrow C_6H_{12}O_6$ + 6H_2O + 6O_2$$

Question 4

During the light reactions of photosynthesis, which of the following occurs as electrons move from photosystem II to photosystem I?

Accepted Answer

ATP is synthesized as protons flow through ATP synthase.

Question 5

Why is the color green least effective at driving photosynthesis in most plants?

Accepted Answer

Green light is reflected by chlorophyll rather than absorbed.

Question 6

Which of the following best describes the role of NADP$$^+ in $$the light reactions of photosynthesis?

Accepted Answer

It acts as a final electron acceptor, becoming reduced to NADPH.

Question 7

A plant is placed in a sealed chamber with only water and light provided. After several hours, the oxygen concentration in the chamber increases. Which process is directly responsible for this increase?

Accepted Answer

The splitting of water molecules during the light reactions.

Question 8

Which of the following is a key difference between C3 and C4 plants in their method of carbon fixation?

Accepted Answer

C3 plants initially fix carbon into a three-carbon compound, while C4 plants initially fix carbon into a four-carbon compound.

Question 9

Which of the following best explains why photorespiration is less likely to occur in C4 and CAM plants compared to C3 plants?

Accepted Answer

C4 and CAM plants have a mechanism to concentrate CO$$_2$$ around Rubisco, reducing oxygenation.

Question 10

Which of the following statements about the Calvin cycle is correct?

Accepted Answer

It uses ATP and NADPH to convert CO$$_2$$ into G3P.

Question 11

A plant cell is supplied with carbon dioxide labeled with a radioactive isotope. After photosynthesis, in which molecule would you expect to find the radioactive label?

Accepted Answer

Glucose ($$C_6H_{12}O_6$)

Question 12

Which of the following best describes the relationship between the light reactions and the Calvin cycle?

Accepted Answer

The light reactions produce ATP and NADPH, which are used in the Calvin cycle.

Question 13

Which of the following is a real-world consequence of the greenhouse effect as described in the study materials?

Accepted Answer

It leads to global warming, a long-term directional change in Earth's climate.

Question 14

If a plant's thylakoid membranes were punctured so that the interior of the thylakoid was no longer separated from the stroma, which process would be most directly affected?

Accepted Answer

The synthesis of ATP via chemiosmosis.

Question 15

Which of the following best explains why two photons of light are required to move electrons from water to NADP$$^+$$ during the light reactions?

Accepted Answer

One photon excites electrons in photosystem II, and a second photon excites electrons in photosystem I.

Question 16

Which of the following is NOT a product of the light reactions of photosynthesis?

Accepted Answer

Glucose

Question 17

Which of the following statements about the role of redox reactions in photosynthesis is correct?

Accepted Answer

H$$_2O is $$oxidized and CO$$_2 is $$reduced.

Question 18

Which of the following would most likely increase the rate of photosynthesis in a typical plant, assuming all other factors are optimal?

Accepted Answer

Increasing the intensity of red and blue light.

Question 19

Which of the following best describes the function of carotenoids in plant cells?

Accepted Answer

They protect chlorophyll from damage by excessive light.

Question 20

A researcher wants to grow plants in a closed environment to maximize their biomass production. Which of the following strategies would most effectively increase the plants' mass over time?

Accepted Answer

Increasing the supply of carbon dioxide in the environment.

Photosynthesis: Using Light to Make Food – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard