Question 1

Which of the following best describes the overall chemical equation for photosynthesis in plants?

Accepted Answer

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

Question 2

Where in the chloroplast do the light-dependent reactions of photosynthesis occur?

Accepted Answer

Thylakoid membranes

Question 3

Which pigment is primarily responsible for absorbing light energy during photosynthesis?

Accepted Answer

Chlorophyll a

Question 4

What is the main purpose of the Calvin Cycle in photosynthesis?

Accepted Answer

To fix carbon dioxide into organic molecules

Question 5

Which of the following environmental factors would most likely decrease the rate of photosynthesis in a C3 plant?

Accepted Answer

Decreasing carbon dioxide concentration

Question 6

Photorespiration occurs when Rubisco binds to which molecule instead of carbon dioxide?

Accepted Answer

Oxygen ($$O_2)$$

Question 7

Which of the following statements about C4 plants is correct?

Accepted Answer

They use a spatial separation of steps to minimize photorespiration.

Question 8

Which of the following is an example of an endergonic reaction in plant metabolism?

Accepted Answer

Photosynthesis

Question 9

What is the role of NADPH in the light-independent reactions of photosynthesis?

Accepted Answer

It acts as an electron donor for the reduction of carbon dioxide.

Question 10

Which of the following best explains why deforestation can negatively impact the global carbon cycle?

Accepted Answer

It reduces the number of plants available to fix atmospheric carbon dioxide.

Question 11

A Venus flytrap captures insects for nutrients. Which statement best describes its energy acquisition?

Accepted Answer

It photosynthesizes for energy but uses insects for additional nutrients.

Question 12

Which of the following is a direct product of the light-dependent reactions of photosynthesis?

Accepted Answer

ATP

Question 13

Which process is the reverse of photosynthesis in terms of energy flow and reactants/products?

Accepted Answer

Cellular respiration

Question 14

Which of the following best describes the function of enzymes in plant metabolism?

Accepted Answer

They act as biological catalysts to speed up chemical reactions.

Question 15

Which wavelength range of the electromagnetic spectrum is most effective for photosynthesis?

Accepted Answer

Visible light (400–700 nm)

Question 16

Which of the following is a consequence of photorespiration in C3 plants?

Accepted Answer

Decreased photosynthetic efficiency

Question 17

Which adaptation allows CAM plants to survive in arid environments?

Accepted Answer

They open their stomata at night to minimize water loss.

Question 18

Which of the following best explains why increasing atmospheric CO2 can enhance plant growth up to a point?

Accepted Answer

CO2 is a reactant in photosynthesis, so more CO2 can increase the rate of carbon fixation.

Question 19

Which of the following is an example of a redox reaction in plant metabolism?

Accepted Answer

The transfer of electrons from water to NADP+ during the light reactions

Question 20

A plant is exposed to high temperatures and intense sunlight. Which adaptation would most likely help it maintain efficient photosynthesis?

Accepted Answer

Using C4 or CAM metabolism to reduce photorespiration

Photosynthesis: Mechanisms, Efficiency, and Significance in Plant Physiology

Study Guide - Practice Questions