Question 1

Which of the following best describes the role of chlorophyll in photosynthesis?

Accepted Answer

It absorbs light energy and transfers it to electrons, initiating the light-dependent reactions.

Question 2

Where do the light-dependent reactions of photosynthesis occur within the chloroplast?

Accepted Answer

In the thylakoid membranes

Question 3

What is the correct balanced equation for the light-dependent reaction of photosynthesis?

Accepted Answer

$$\mathrm{H_2O + NADP^+ + ADP \rightarrow O_2$ + NADPH + ATP}$$

Question 4

Which structure within the chloroplast is directly involved in the synthesis of ATP during photosynthesis?

Accepted Answer

Thylakoid membrane

Question 5

During the light-dependent reactions, what is the immediate source of electrons that replace those lost by Photosystem II (PS-II)?

Accepted Answer

Electrons from the splitting of water ($$H_2O)$$

Question 6

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

Accepted Answer

Glucose ($$C_6H_{12}O_6$)

Question 7

What is the main function of the Calvin-Benson cycle in photosynthesis?

Accepted Answer

To fix atmospheric CO$$_2$$ into organic molecules using ATP and NADPH

Question 8

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

Accepted Answer

Carbon fixation

Question 9

What is the summary equation for the Calvin-Benson cycle for the production of one glucose molecule?

Accepted Answer

$$\mathrm{6CO_2 + 18 ATP + 12 NADPH \rightarrow C_6H_{12}O_6$ + 18 ADP + 12 NADP^+}$$

Question 10

Which process is responsible for the synthesis of ATP during the light-dependent reactions?

Accepted Answer

Photophosphorylation via chemiosmosis

Question 11

If a plant is exposed only to light with a wavelength of 800 nm, which of the following is most likely to occur?

Accepted Answer

Photosynthesis will decrease because 800 nm is outside the range of visible light absorbed by chlorophyll.

Question 12

Which of the following statements about photosystems is correct?

Accepted Answer

Photosystem II (PS-II) absorbs light and initiates electron flow that leads to ATP synthesis.

Question 13

Which of the following best explains why plants are a primary energy source for most living organisms?

Accepted Answer

They synthesize energy-rich organic molecules from energy-poor molecules using sunlight.

Question 14

What is the role of accessory pigments such as carotenoids and phycocyanins in photosynthesis?

Accepted Answer

They absorb different wavelengths of light and transfer energy to chlorophyll.

Question 15

During chemiosmosis in the light-dependent reactions, what drives the synthesis of ATP?

Accepted Answer

The diffusion of protons (H$$^+) $$down their concentration gradient across the thylakoid membrane

Question 16

Which of the following is a direct product of the splitting of water during the light-dependent reactions?

Accepted Answer

Oxygen gas ($$O_2)$$

Question 17

A mutation prevents the regeneration of ribulose bisphosphate in the Calvin-Benson cycle. What is the most immediate consequence?

Accepted Answer

Carbon fixation will cease, halting glucose production.

Question 18

Which of the following best describes the relationship between the light-dependent and light-independent reactions?

Accepted Answer

The light-dependent reactions provide ATP and NADPH used in the light-independent reactions to fix CO$$_2.$$

Question 19

Which of the following would most likely result if the thylakoid membranes were damaged in a plant cell?

Accepted Answer

ATP and NADPH production during the light-dependent reactions would decrease.

Question 20

A scientist exposes a plant to a chemical that blocks the electron transport system in Photosystem II. Which of the following outcomes is most likely?

Accepted Answer

ATP and NADPH production will decrease, limiting glucose synthesis.

Photosynthesis: Capturing Solar Energy in Plants

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