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

Question 1

Which structure in the leaf is primarily responsible for gas exchange between the plant and the atmosphere?

Accepted Answer

Stomata

Question 2

What is the main pigment responsible for the green color of plants, and what wavelengths does it absorb most efficiently?

Accepted Answer

Chlorophyll; absorb blue and red wavelengths

Question 3

During the light reactions of photosynthesis, what is the immediate source of electrons for Photosystem II?

Accepted Answer

Water ($$H_2O)$$

Question 4

Which equation correctly summarizes the overall process of photosynthesis?

Accepted Answer

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

Question 5

In the Calvin Cycle, which enzyme is responsible for carbon fixation?

Accepted Answer

Rubisco

Question 6

What is the main function of the thylakoid membrane in chloroplasts?

Accepted Answer

Site of light-dependent reactions

Question 7

Which molecule acts as the final electron acceptor in the light reactions of photosynthesis?

Accepted Answer

NADP+

Question 8

Why do plants appear green to our eyes?

Accepted Answer

They reflect green light and absorb blue and red

Question 9

Which of the following best describes the role of ATP and NADPH in the Calvin Cycle?

Accepted Answer

They provide energy and electrons for carbon fixation and reduction

Question 10

During the light reactions, protons ($$H^+) $$are pumped into the thylakoid space. What is the primary purpose of this proton gradient?

Accepted Answer

To drive ATP synthesis via ATP synthase

Question 11

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

Accepted Answer

Glucose ($$C_6H_{12}O_6$)

Question 12

A plant is exposed only to green light. What would you expect to happen to its rate of photosynthesis?

Accepted Answer

It would decrease, since green light is mostly reflected

Question 13

Which structure in the chloroplast is the site of the Calvin Cycle?

Accepted Answer

Stroma

Question 14

What is the main purpose of splitting water ($$H_2O) $$during the light reactions?

Accepted Answer

To provide electrons to replace those lost by Photosystem II

Question 15

Which of the following best describes the relationship between oxidation and reduction in photosynthesis?

Accepted Answer

Oxidation and reduction are coupled; as water is oxidized, NADP+ is reduced

Question 16

In a scenario where stomata are closed due to drought, what is the most likely effect on photosynthesis?

Accepted Answer

Photosynthesis decreases due to limited $$CO_2$$ uptake

Question 17

Which of the following is a correct sequence of events in the light-dependent reactions?

Accepted Answer

Light excites electrons in Photosystem II → electrons travel down ETC → water is split → ATP is produced → electrons reduce NADP+

Question 18

Which molecule is regenerated at the end of the Calvin Cycle to allow the cycle to continue?

Accepted Answer

RuBP

Question 19

If a plant cell is placed in an environment with no light, which process will be directly affected first?

Accepted Answer

Light-dependent reactions

Question 20

Which of the following best explains why carotenoids are important for plants?

Accepted Answer

They absorb green and blue light, expanding the range of light usable for photosynthesis

Photosynthesis: Structure, Function, and Mechanisms in Plants

Study Guide - Practice Questions