Question 1

Which pigment is primarily responsible for the absorption of light in the blue and red regions of the visible spectrum during photosynthesis?

Accepted Answer

Chlorophyll a

Question 2

What is the main reason leaves appear green to our eyes?

Accepted Answer

Chlorophyll reflects green light

Question 3

During the light-dependent reactions of photosynthesis, what is the immediate source of electrons for the electron transport chain in Photosystem II?

Accepted Answer

Water ($$H_2O)$$

Question 4

Which of the following best describes the role of ATP synthase in the thylakoid membrane?

Accepted Answer

It synthesizes ATP as protons flow down their gradient

Question 5

What is the main product of the Calvin cycle that can be used to synthesize glucose?

Accepted Answer

Glyceraldehyde-3-phosphate (G3P)

Question 6

Which enzyme catalyzes the fixation of carbon dioxide in the Calvin cycle?

Accepted Answer

Rubisco

Question 7

If a plant is exposed only to green light, what would most likely happen to its rate of photosynthesis?

Accepted Answer

It would decrease because chlorophyll reflects green light

Question 8

Which of the following is a direct byproduct of the splitting of water during the light reactions?

Accepted Answer

Oxygen ($$O_2)$$

Question 9

How many molecules of ATP and NADPH are required to synthesize one molecule of glucose ($$C_6H_{12}O_6$) via the Calvin cycle?

Accepted Answer

$$18$$ ATP and $$12$$ NADPH

Question 10

Which statement best explains why carotenoids become more visible in leaves during autumn?

Accepted Answer

Chlorophyll breaks down, revealing carotenoids

Question 11

What is the primary function of NADPH in the Calvin cycle?

Accepted Answer

To reduce 3-phosphoglycerate (PGA) to G3P

Question 12

Which of the following best describes chemiosmosis in the context of photosynthesis?

Accepted Answer

The synthesis of ATP driven by the flow of protons through ATP synthase

Question 13

A mutation disables the enzyme rubisco in a plant. Which process would be directly affected?

Accepted Answer

The fixation of carbon dioxide in the Calvin cycle

Question 14

Which of the following sequences correctly represents the flow of electrons during the light reactions of photosynthesis?

Accepted Answer

Water → Photosystem II → Photosystem I → NADP+

Question 15

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

Accepted Answer

NADP+

Question 16

If the thylakoid membrane becomes leaky to protons ($$H^+$$), what would be the most immediate effect on photosynthesis?

Accepted Answer

Decreased ATP synthesis due to loss of proton gradient

Question 17

Which of the following best explains why two molecules of G3P are needed to form one molecule of glucose ($$C_6H_{12}O_6$)?

Accepted Answer

Each G3P contains three carbons, and glucose contains six

Question 18

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

Accepted Answer

Glucose ($$C_6H_{12}O_6$)

Question 19

A plant is genetically modified to lack carotenoids. Which of the following would most likely occur?

Accepted Answer

The plant would be more susceptible to damage from excess light

Question 20

Which of the following best describes the relationship between the light reactions and the Calvin cycle?

Accepted Answer

The light reactions provide ATP and NADPH for the Calvin cycle

Photosynthesis: Light Reactions and the Calvin Cycle

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