Question 1

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

Accepted Answer

$$6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2$$

Question 2

Which molecule is oxidized and which is reduced during photosynthesis?

Accepted Answer

$$\mathrm{H}_2\mathrm{O} is $$oxidized and $$\mathrm{CO}_2 is $$reduced

Question 3

What is the primary function of the light reactions in photosynthesis?

Accepted Answer

To generate ATP and NADPH for the Calvin cycle

Question 4

Which pigment is directly involved in the light reactions of photosynthesis?

Accepted Answer

Chlorophyll a

Question 5

Why do leaves appear green to the human eye?

Accepted Answer

They reflect and transmit green light while absorbing violet-blue and red light

Question 6

Which of the following best explains why the action spectrum for photosynthesis is broader than the absorption spectrum of chlorophyll a?

Accepted Answer

Accessory pigments such as chlorophyll b and carotenoids absorb additional wavelengths

Question 7

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

Accepted Answer

It donates electrons to replace those lost by chlorophyll in photosystem II

Question 8

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

Accepted Answer

Protons are pumped into the thylakoid space and diffuse back into the stroma through ATP synthase

Question 9

During the Calvin cycle, what is the first stable product formed after carbon dioxide is fixed?

Accepted Answer

3-phosphoglycerate (3-PGA)

Question 10

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

Accepted Answer

Rubisco (RuBP carboxylase-oxygenase)

Question 11

What is the main purpose of cyclic electron flow in the light reactions?

Accepted Answer

To produce additional ATP without generating NADPH or O2

Question 12

Which of the following best describes the relationship between photosynthesis and cellular respiration?

Accepted Answer

Photosynthesis stores energy in organic molecules, while cellular respiration releases energy from organic molecules

Question 13

A plant is exposed only to green light. What will happen to its rate of photosynthesis?

Accepted Answer

It will decrease because green light is mostly reflected and not absorbed

Question 14

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

Accepted Answer

Both use chemiosmosis to generate ATP, but the source of high-energy electrons differs

Question 15

If a plant's thylakoid membranes were punctured so that the interior of the thylakoid was no longer separated from the stroma, which process would be most directly affected?

Accepted Answer

The synthesis of ATP

Question 16

How many turns of the Calvin cycle are required to produce one net molecule of glyceraldehyde 3-phosphate (G3P)?

Accepted Answer

Three

Question 17

Which of the following best explains why carotenoids are important to plants?

Accepted Answer

They broaden the spectrum of light that can drive photosynthesis and protect chlorophyll from damage

Question 18

What is the fate of the oxygen atoms in water molecules during photosynthesis?

Accepted Answer

They are released as molecular oxygen ($$\mathrm{O}_2)$$

Question 19

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

Accepted Answer

Glucose

Question 20

A mutation in a plant prevents the production of NADP+ reductase. Which of the following would be most directly affected?

Accepted Answer

The reduction of NADP+ to NADPH

Photosynthesis: Mechanisms, Structures, and Significance

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