$$6\ \text{CO}_2 + 6\ \text{H}_2\text{O} + \text{Light Energy} \rightarrow 6\ \text{O}_2 + \text{C}_6\text{H}_{12}\text{O}_6$$

Question 1

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

Accepted Answer

Autotrophs produce organic molecules from CO$$_2$$ and other raw materials, while heterotrophs rely on organic molecules produced by other organisms.

Question 2

What is the correct summary equation for photosynthesis?

Accepted Answer

$$6\ 	ext{CO}_2 + 6\ 	ext{H}_2	ext{O} + 	ext{Light Energy} ightarrow 6\ 	ext{O}_2 + 	ext{C}_6	ext{H}_{12}	ext{O}_6$$

Question 3

Which component of the chloroplast is the site of the light reactions?

Accepted Answer

Thylakoid membrane

Question 4

What is the main pigment responsible for absorbing light in plants?

Accepted Answer

Chlorophyll a

Question 5

Why are leaves green?

Accepted Answer

Leaves reflect green light and absorb blue and red light.

Question 6

Which wavelengths of light are most effective for photosynthesis?

Accepted Answer

Red (650-700 nm) and blue (400-500 nm)

Question 7

What happens when a solution of chlorophyll a absorbs photons?

Accepted Answer

Electrons are excited and energy is released as heat and fluorescence.

Question 8

Which of the following is NOT a component of a photosystem?

Accepted Answer

ATP synthase

Question 9

During linear electron flow in the light reactions, what is the final electron acceptor?

Accepted Answer

NADP$$^+$$

Question 10

Which photosystem functions first in the light reactions?

Accepted Answer

Photosystem II (PS II)

Question 11

What is the main product of the Calvin cycle?

Accepted Answer

Glyceraldehyde-3-phosphate (G3P)

Question 12

How many turns of the Calvin cycle are required to produce one molecule of glucose?

Accepted Answer

6

Question 13

Which molecule acts as the CO$$_2$$ acceptor in the Calvin cycle?

Accepted Answer

Ribulose bisphosphate (RuBP)

Question 14

Which process generates ATP in both mitochondria and chloroplasts?

Accepted Answer

Chemiosmosis

Question 15

What is the main difference between chemiosmosis in mitochondria and chloroplasts?

Accepted Answer

Mitochondria pump protons into the intermembrane space, chloroplasts pump protons into the thylakoid space.

Question 16

Which of the following statements about cyclic electron flow is correct?

Accepted Answer

It produces ATP but not NADPH.

Question 17

In the Calvin cycle, what is the role of ATP and NADPH?

Accepted Answer

They provide energy and reducing power for the synthesis of G3P.

Question 18

Which phase of the Calvin cycle involves the incorporation of CO$$_2$$ into an organic molecule?

Accepted Answer

Carbon fixation

Question 19

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

Accepted Answer

It would decrease because green light is mostly reflected.

Question 20

Which of the following best explains why the action spectrum for photosynthesis differs from the absorption spectrum for chlorophyll a?

Accepted Answer

The action spectrum includes the effects of accessory pigments such as chlorophyll b and carotenoids.

Chapter 10: Photosynthesis – Structure, Function, and Mechanisms

Study Guide - Practice Questions