$$6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + \text{light energy} \rightarrow C_6H_{12}O_6$ + 6\ \mathrm{O}_2$$

Question 1

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

Accepted Answer

$$6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 	ext{light energy} ightarrow C_6H_{12}O_6$ + 6\ \mathrm{O}_2$$

Question 2

Which structure in a plant leaf is primarily responsible for gas exchange, allowing CO$$_2 to $$enter and O$$_2 to $$exit during photosynthesis?

Accepted Answer

Stomata

Question 3

During the light reactions of photosynthesis, which molecule is oxidized and which is reduced?

Accepted Answer

Water is oxidized; NADP$$^+ is $$reduced

Question 4

Which of the following best describes the role of chlorophyll a in photosynthesis?

Accepted Answer

It absorbs mainly blue-violet and red light and directly participates in the light reactions.

Question 5

What is the main function of the Calvin cycle in photosynthesis?

Accepted Answer

To use ATP and NADPH to convert CO$$_2$$ into G3P (a sugar precursor)

Question 6

Which of the following statements about the electron transport chain in the light reactions is correct?

Accepted Answer

It creates a proton gradient across the thylakoid membrane, which drives ATP synthesis via chemiosmosis.

Question 7

Which compound is recycled during the Calvin cycle and is essential for the fixation of CO$$_2$$?

Accepted Answer

Ribulose bisphosphate (RuBP)

Question 8

Photorespiration is considered wasteful for C$$_3$$ plants because:

Accepted Answer

It consumes O$$_2$$ and releases CO$$_2$$, reducing the efficiency of photosynthesis.

Question 9

Which adaptation allows CAM plants to survive in arid environments?

Accepted Answer

They fix CO$$_2 at $$night and store it as organic acids for use during the day.

Question 10

Which of the following is a greenhouse gas that contributes to the greenhouse effect?

Accepted Answer

Carbon dioxide (CO$$_2)$$

Question 11

In the light reactions, what is the immediate source of electrons for the electron transport chain?

Accepted Answer

Water (H$$_2O)$$

Question 12

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

Accepted Answer

Rubisco

Question 13

Which of the following best describes the difference between autotrophs and heterotrophs?

Accepted Answer

Autotrophs produce their own organic molecules from CO$$_2$$; heterotrophs obtain organic molecules by consuming other organisms.

Question 14

Which pigment is primarily responsible for the green color of leaves and is most efficient at absorbing red and blue wavelengths?

Accepted Answer

Chlorophyll a

Question 15

In C$$_4$$ plants, how is photorespiration minimized?

Accepted Answer

CO$$_2 is $$initially fixed into a four-carbon compound in mesophyll cells, then released in bundle-sheath cells for the Calvin cycle.

Question 16

Which of the following best explains why plants appear green to the human eye?

Accepted Answer

Chlorophyll reflects green wavelengths of light.

Question 17

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

Accepted Answer

Glucose

Question 18

A scientist exposes a plant to only green light. 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 19

Which of the following best describes the greenhouse effect?

Accepted Answer

The warming of Earth due to atmospheric accumulation of CO$$_2$$ and other gases, which absorb and reradiate infrared radiation.

Question 20

Which of the following correctly matches the location with the process in photosynthesis?

Accepted Answer

Light reactions occur in the thylakoid membranes; Calvin cycle occurs in the stroma.

Step-by-Step Study Guide for Photosynthesis (General Biology I)

Guida di studio - Domande di pratica