Q: Which of the following best describes the overall chemical equation for photosynthesis?

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

Q: During the light reactions of photosynthesis, what is the primary function of the electron transport chain?

To pump protons ($$\text{H}^+) $$into the thylakoid space, creating a proton gradient used to synthesize ATP

Q: Which of the following best explains why the thylakoid space (lumen) has a low pH during the light reactions?

Protons ($$\text{H}^+) $$are pumped into the thylakoid space, increasing its acidity

Question 1

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

Accepted Answer

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

Question 2

During the light reactions of photosynthesis, what is the primary function of the electron transport chain?

Accepted Answer

To pump protons ($$	ext{H}^+) $$into the thylakoid space, creating a proton gradient used to synthesize ATP

Question 3

Which molecule is oxidized and which is reduced during photosynthesis?

Accepted Answer

Water is oxidized to oxygen; carbon dioxide is reduced to glucose

Question 4

What is the main role of chlorophyll in photosynthesis?

Accepted Answer

To absorb light energy and transfer it to electrons

Question 5

Where in the chloroplast does the Calvin cycle take place?

Accepted Answer

In the stroma

Question 6

A plant is exposed to a green light bulb. What would you expect to happen to the rate of photosynthesis and why?

Accepted Answer

The rate of photosynthesis would decrease because chlorophyll reflects green light rather than absorbing it

Question 7

Which of the following is the final electron acceptor in the light reactions of photosynthesis?

Accepted Answer

NADP$$^+$$

Question 8

If the thylakoid membrane is punctured so that the interior is no longer separated from the stroma, which process would be most directly affected?

Accepted Answer

ATP synthesis via chemiosmosis

Question 9

Which of the following best explains why the Calvin cycle is sometimes called the 'dark reactions'?

Accepted Answer

It does not require light directly and can occur in the absence of light if ATP and NADPH are available

Question 10

A scientist uses radioactive $$^{14}CO$_2 to $$track carbon in a plant. After photosynthesis, radioactivity is found in sugars, lipids, and proteins. What does this indicate?

Accepted Answer

Carbon fixed during photosynthesis is used to synthesize a variety of biomolecules

Question 11

Which of the following best describes the relationship between the products and reactants of photosynthesis and cellular respiration?

Accepted Answer

The products of photosynthesis are the reactants of cellular respiration and vice versa

Question 12

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

Accepted Answer

Glucose

Question 13

What is the main purpose of the Calvin cycle?

Accepted Answer

To fix carbon dioxide and produce G3P, which can be used to form glucose and other organic molecules

Question 14

Which of the following best explains why the thylakoid space (lumen) has a low pH during the light reactions?

Accepted Answer

Protons ($$	ext{H}^+) $$are pumped into the thylakoid space, increasing its acidity

Question 15

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

Accepted Answer

Light excites electrons in photosystem II, electrons move through the electron transport chain, ATP and NADPH are produced

Question 16

Which of the following is a real-world consequence of phytoplankton photosynthesis?

Accepted Answer

Phytoplankton produce a significant portion of the world's oxygen supply

Question 17

Which of the following best describes the fate of G3P produced in the Calvin cycle?

Accepted Answer

It can be used to synthesize glucose, fatty acids, amino acids, and other organic molecules

Question 18

If a plant is kept in the dark, which of the following would you expect to increase in concentration in the chloroplast?

Accepted Answer

NADP$$^+$$

Question 19

Which of the following is a correct distinction between autotrophs and heterotrophs?

Accepted Answer

Autotrophs can nourish themselves beginning with CO$$_2$$ and other inorganic nutrients

Photosynthesis: Structure, Function, and Mechanisms

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