Question 1

Which of the following best explains why plants appear green to the human eye?

Accepted Answer

Chlorophyll reflects green wavelengths and absorbs red and blue.

Question 2

What is the primary function of carotenoids in plant cells during photosynthesis?

Accepted Answer

To protect chlorophyll from free radical damage and absorb wavelengths chlorophyll cannot.

Question 3

Which equation correctly summarizes the overall process of photosynthesis?

Accepted Answer

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

Question 4

A plant treated with a herbicide that blocks carotenoid synthesis will most likely:

Accepted Answer

Turn white and die due to loss of chlorophyll protection.

Question 5

Which of the following best describes the role of the thylakoid membrane in photosynthesis?

Accepted Answer

It houses pigments and the electron transport chain for the light-dependent reactions.

Question 6

During the light-dependent reactions of photosynthesis, what is the immediate fate of the excited electron from chlorophyll?

Accepted Answer

It is transferred to an electron carrier, initiating the electron transport chain.

Question 7

Which of the following is a direct product of the Calvin cycle (light-independent reactions) in photosynthesis?

Accepted Answer

Glyceraldehyde-3-phosphate (G3P)

Question 8

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

Accepted Answer

It would decrease because green light is mostly reflected, not absorbed.

Question 9

Which of the following statements about photosystems is correct?

Accepted Answer

Photosystems are clusters of pigments and proteins that work together to capture light energy.

Question 10

What is the main purpose of the proton (H$$^+) $$gradient established across the thylakoid membrane during photosynthesis?

Accepted Answer

To drive the synthesis of ATP via ATP synthase.

Question 11

A mutation causes a plant to lack functional accessory pigments. Which of the following would most likely result?

Accepted Answer

The plant would be more susceptible to damage from free radicals.

Question 12

Which of the following best describes the transformation that occurs at the reaction center of a photosystem?

Accepted Answer

Light energy is converted into chemical energy via a redox reaction.

Question 13

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

Accepted Answer

Directly producing oxygen during the light reactions.

Question 14

Which of the following is most analogous to the electron transport chain in cellular respiration?

Accepted Answer

The light-dependent electron transport chain in the thylakoid membrane.

Question 15

A scientist exposes a plant to only blue and red light. What is the expected effect on photosynthesis and why?

Accepted Answer

Photosynthesis will be maximized because chlorophyll absorbs blue and red light most efficiently.

Question 16

Which of the following best explains why regeneration of carriers is essential in both photosynthesis and cellular respiration?

Accepted Answer

Without regeneration, the electron transport chain would halt, stopping ATP production.

Question 17

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

Accepted Answer

Light absorption by pigments $$\rightarrow$$ excitation of electrons $$\rightarrow$$ electron transport chain $$\rightarrow$$ ATP and NADPH production

Question 18

A leaf appears yellow in the fall because:

Accepted Answer

Chlorophyll breaks down, leaving carotenoids that reflect yellow and orange light.

Question 19

Which of the following statements about the stroma of the chloroplast is correct?

Accepted Answer

It is the site where the Calvin cycle occurs.

Question 20

If a plant's thylakoid membranes were damaged, which process would be most directly affected?

Accepted Answer

The light-dependent reactions, including ATP and NADPH production.

Photosynthesis: Structure, Pigments, and Mechanisms

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