Question 1

Which of the following best describes the main function of the Calvin cycle in photosynthesis?

Accepted Answer

To fix carbon dioxide and synthesize glyceraldehyde-3-phosphate (G3P)

Question 2

A plant is placed under green light only. Which statement best explains what happens to its rate of photosynthesis?

Accepted Answer

It decreases because green light is mostly reflected, not absorbed, by chlorophyll

Question 3

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

Accepted Answer

$$6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2$$

Question 4

Which pigment is primarily responsible for the absorption of light in the light reactions of photosynthesis?

Accepted Answer

Chlorophyll a

Question 5

A plant that opens its stomata at night to minimize water loss and stores CO$$_2 as $$malic acid is most likely a:

Accepted Answer

CAM plant

Question 6

Which of the following best explains why photorespiration is considered wasteful for plants?

Accepted Answer

It consumes O$$_2$$ and releases CO$$_2$$ without producing sugar

Question 7

In the light reactions, the linear electron flow results in the production of which molecules?

Accepted Answer

ATP and NADPH

Question 8

Which structure within the chloroplast is the site of the light-dependent reactions?

Accepted Answer

Thylakoid membrane

Question 9

A scientist uses a spectrophotometer to measure the absorption spectrum of a pigment. What information does this provide?

Accepted Answer

The wavelengths of light absorbed by the pigment

Question 10

Which enzyme catalyzes the first step of carbon fixation in the Calvin cycle?

Accepted Answer

Rubisco

Question 11

If a plant's thylakoid membranes are damaged, which process would be most directly affected?

Accepted Answer

Light reactions

Question 12

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

Accepted Answer

It is reduced to NADPH, which carries electrons to the Calvin cycle

Question 13

A plant is exposed to light with a wavelength of 700 nm. Which photosystem is primarily activated?

Accepted Answer

Photosystem I (PS I)

Question 14

Which of the following is a correct sequence of events in the linear electron flow of the light reactions?

Accepted Answer

Excitation of PS II → Electron transport chain → Excitation of PS I → NADP$$^+$$ reduction

Question 15

Which of the following best explains why C$$_4$$ plants are more efficient than C$$_3$$ plants in hot, dry environments?

Accepted Answer

C$$_4$$ plants spatially separate carbon fixation from the Calvin cycle, reducing photorespiration

Question 16

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

Accepted Answer

G3P

Question 17

A mutation causes a plant to lack carotenoids. Which of the following is a likely consequence?

Accepted Answer

The plant will be more susceptible to damage from excess light energy

Question 18

Which of the following best describes the action spectrum of photosynthesis?

Accepted Answer

The rate of photosynthesis at different wavelengths of light

Question 19

Which of the following statements about autotrophs and heterotrophs is correct?

Accepted Answer

Autotrophs convert inorganic molecules into organic molecules using energy from light or chemicals

Question 20

A plant is placed in an environment with high oxygen and low carbon dioxide concentrations. Which process is most likely to increase?

Accepted Answer

Photorespiration

Photosynthesis: Key Concepts and Vocabulary

Study Guide - Practice Questions