Question 1

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

Accepted Answer

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

Question 2

In the context of photosynthesis, what is the primary function of the light-dependent reactions?

Accepted Answer

To produce ATP and NADPH for use in the Calvin cycle

Question 3

Which structure within the chloroplast is the site of the light-dependent reactions?

Accepted Answer

Thylakoid membrane

Question 4

Which pigment is primarily responsible for absorbing light energy in plants and cyanobacteria?

Accepted Answer

Chlorophyll a

Question 5

What is the role of accessory pigments in photosynthesis?

Accepted Answer

They expand the range of wavelengths absorbed for photosynthesis

Question 6

Which of the following best explains why purple sulfur bacteria do not release oxygen during photosynthesis?

Accepted Answer

They use hydrogen sulfide ($H_2S$) instead of water as an electron donor

Question 7

A photon of light with a wavelength of 450 nm has more energy than a photon with a wavelength of 650 nm. Which equation best describes the relationship between energy ($E$) and wavelength ($\lambda$)?

Accepted Answer

$E \propto \frac{1}{\lambda}$

Question 8

Which of the following is a correct description of the absorption spectrum of chlorophyll a?

Accepted Answer

It shows strong absorption in the blue and red regions of visible light

Question 9

During the light-dependent reactions, what is the immediate result of a photon striking a chlorophyll molecule?

Accepted Answer

An electron is excited to a higher energy level

Question 10

Which of the following best describes the function of the Calvin cycle in photosynthesis?

Accepted Answer

It uses ATP and NADPH to fix $CO_2$ into organic molecules

Question 11

If a plant is exposed only to 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 12

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

Accepted Answer

Glucose ($C_6H_{12}O_6$)

Question 13

Which part of the chloroplast contains the enzymes required for the Calvin cycle?

Accepted Answer

Stroma

Question 14

A scientist discovers a new photosynthetic organism that does not produce oxygen. Which type of photosynthesis does this organism most likely perform?

Accepted Answer

Anoxygenic photosynthesis

Question 15

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

Accepted Answer

Grana are stacks of thylakoid membranes where light-dependent reactions occur

Question 16

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

Accepted Answer

NADP$^+$

Question 17

If the thylakoid membrane is damaged, which process would be directly affected?

Accepted Answer

Production of ATP and NADPH during the light-dependent reactions

Question 18

Which of the following best explains why accessory pigments are important for photosynthetic organisms living in low-light ocean areas?

Accepted Answer

They allow absorption of wavelengths not captured by chlorophyll a

Question 19

Which of the following is a real-world consequence of the discovery that living vegetation adds oxygen to the air?

Accepted Answer

Forests play a critical role in maintaining atmospheric oxygen levels

Question 20

A mutation prevents a plant from producing ATP during the light-dependent reactions. What is the most immediate effect on the Calvin cycle?

Accepted Answer

The Calvin cycle would slow down or stop due to lack of energy

Photosynthesis: Mechanisms, Structures, and Processes

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