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

Question 1

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

Accepted Answer

$$6CO_2 + 6H_2O + 	ext{light energy} ightarrow C_6H_{12}O_6$ + 6O_2$$

Question 2

What is the primary function of chlorophyll in photosynthesis?

Accepted Answer

To absorb light energy and transfer it to electrons

Question 3

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

Accepted Answer

Thylakoid membrane

Question 4

During the light reactions of photosynthesis, what is the fate of the electrons derived from water?

Accepted Answer

They are transferred to NADP$$^+ to $$form NADPH

Question 5

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 6

What is the role of ATP synthase in photosynthesis?

Accepted Answer

It synthesizes ATP as protons flow through it from the thylakoid lumen to the stroma

Question 7

Which pigment is primarily responsible for the green color of plants and absorbs red and violet-blue light most efficiently?

Accepted Answer

Chlorophyll a

Question 8

Why do C$$_4$$ plants have an advantage over C$$_3$$ plants in hot, dry environments?

Accepted Answer

C$$_4$$ plants use PEP carboxylase, which has a higher affinity for CO$$_2$$ and does not bind O$$_2$$

Question 9

What is photorespiration and why is it considered wasteful for plants?

Accepted Answer

It occurs when rubisco binds O$$_2$$ instead of CO$$_2$$, consuming ATP and releasing CO$$_2$$ without producing sugar

Question 10

Which of the following best explains why CAM plants are adapted to arid environments?

Accepted Answer

They open their stomata at night to minimize water loss and fix CO$$_2$$ into organic acids

Question 11

A plant is exposed to light of only green wavelengths. What is the most likely effect on the rate of photosynthesis?

Accepted Answer

The rate of photosynthesis will decrease because green light is mostly reflected, not absorbed

Question 12

Which enzyme is responsible for the initial fixation of CO$$_2 in $$the Calvin cycle?

Accepted Answer

Rubisco

Question 13

In the light reactions, what is the main purpose of the electron transport chain between photosystem II and photosystem I?

Accepted Answer

To create a proton gradient for ATP synthesis

Question 14

Which of the following is a correct description of cyclic electron flow in photosynthesis?

Accepted Answer

It involves only photosystem I and produces ATP but not NADPH or O$$_2$$

Question 15

A mutation causes a plant to lack functional ATP synthase in its thylakoid membranes. Which process would be directly affected?

Accepted Answer

Synthesis of ATP during the light reactions

Question 16

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

Accepted Answer

The light reactions provide ATP and NADPH to the Calvin cycle

Question 17

Which of the following is a real-world consequence of photorespiration in crop plants?

Accepted Answer

It can reduce crop yields by wasting fixed carbon and energy

Question 18

What is the main adaptive advantage of the C$$_4$$ pathway in plants such as corn and sugarcane?

Accepted Answer

It minimizes photorespiration by spatially separating carbon fixation from the Calvin cycle

Question 19

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

Accepted Answer

Autotrophs produce organic molecules from inorganic sources, while heterotrophs consume organic molecules produced by others

Chapter 10: Photosynthesis – Microbiology Study Notes

Study Guide - Practice Questions