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

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

Question 1

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

Accepted Answer

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

Question 2

What is the primary function of the light-harvesting complexes in a photosystem?

Accepted Answer

To funnel photon energy to the reaction-center complex

Question 3

During the light reactions, what is the immediate fate of the electrons excited in Photosystem II (PS II)?

Accepted Answer

They are transferred to the primary electron acceptor of PS II

Question 4

Which of the following statements about chemiosmosis in chloroplasts is correct?

Accepted Answer

Protons are pumped into the thylakoid space, creating a gradient used by ATP synthase to generate ATP

Question 5

What is the main role of NADPH produced during the light reactions?

Accepted Answer

To provide reducing power for the Calvin cycle

Question 6

Which pigment is primarily responsible for absorbing light energy in the light reactions of photosynthesis?

Accepted Answer

Chlorophyll a

Question 7

Why do C4 plants have an advantage over C3 plants in hot, dry environments?

Accepted Answer

They use PEP carboxylase to initially fix CO2, minimizing photorespiration

Question 8

Which of the following best explains why photorespiration is considered wasteful for plants?

Accepted Answer

It consumes ATP and does not produce sugar

Question 9

What is the role of water in the light reactions of photosynthesis?

Accepted Answer

It donates electrons to replace those lost by P680 in Photosystem II

Question 10

Which process occurs in the stroma of the chloroplast?

Accepted Answer

The Calvin cycle

Question 11

A plant is exposed to light, but its thylakoid membranes are damaged so that protons can freely cross the membrane. What is the most likely consequence?

Accepted Answer

ATP synthesis would decrease because the proton gradient could not be maintained

Question 12

Which of the following is a correct comparison between mitochondria and chloroplasts?

Accepted Answer

Both use chemiosmosis to generate ATP via ATP synthase

Question 13

Which of the following is true about cyclic electron flow in the light reactions?

Accepted Answer

It produces ATP but not NADPH

Question 14

What is the immediate product of carbon fixation in the Calvin cycle?

Accepted Answer

A three-carbon molecule (3-phosphoglycerate)

Question 15

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

Accepted Answer

RuBisCO

Question 16

A desert plant opens its stomata only at night and stores CO2 in organic acids. During the day, it closes its stomata and uses the stored CO2 for the Calvin cycle. What type of plant is this?

Accepted Answer

CAM plant

Question 17

Which of the following best describes the fate of the oxygen atoms from water molecules during photosynthesis?

Accepted Answer

They are released as O2 gas

Question 18

If a plant is placed in an environment with only green light, what would you expect to happen to its rate of photosynthesis?

Accepted Answer

It would decrease because chlorophyll a reflects green light

Question 19

Which of the following is a direct product of the Calvin cycle that can be used to synthesize glucose and other organic molecules?

Accepted Answer

Glyceraldehyde-3-phosphate (G3P)

Question 20

Which of the following is NOT a function of carotenoids in photosynthesis?

Accepted Answer

Fixing carbon dioxide in the Calvin cycle

Photosynthesis: Mechanisms and Adaptations

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