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

Question 1

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

Accepted Answer

$$6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} + 	ext{light energy} ightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2$$

Question 2

Which structure within the chloroplast is the primary site of the light reactions of photosynthesis?

Accepted Answer

Thylakoid membrane

Question 3

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

Accepted Answer

To use ATP and NADPH to convert $$\mathrm{CO}_2$$ into sugar

Question 4

Which pigment is directly involved in the light reactions by transferring excited electrons to the primary electron acceptor?

Accepted Answer

Chlorophyll a

Question 5

Why do leaves appear green to the human eye?

Accepted Answer

Chlorophyll absorbs violet-blue and red light, reflecting and transmitting green light

Question 6

Which of the following statements about cyclic electron flow in the light reactions is correct?

Accepted Answer

It produces ATP but not NADPH or oxygen

Question 7

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

Accepted Answer

It is split to provide electrons and protons, releasing oxygen as a by-product

Question 8

Which enzyme catalyzes the fixation of $$\mathrm{CO}_2 in $$the Calvin cycle?

Accepted Answer

Rubisco (ribulose bisphosphate carboxylase-oxygenase)

Question 9

In which part of the chloroplast does the Calvin cycle take place?

Accepted Answer

Stroma

Question 10

Which of the following best explains why photorespiration is considered wasteful for most plants?

Accepted Answer

It consumes organic fuel and releases $$\mathrm{CO}_2$$ without producing ATP or sugar

Question 11

How do C4 plants minimize photorespiration?

Accepted Answer

By initially fixing $$\mathrm{CO}_2$$ into a four-carbon compound in mesophyll cells

Question 12

Which of the following is a key difference between chemiosmosis in mitochondria and chloroplasts?

Accepted Answer

In chloroplasts, protons are pumped into the thylakoid space; in mitochondria, into the intermembrane space

Question 13

Which of the following is a product of the light reactions that is used in the Calvin cycle?

Accepted Answer

NADPH

Question 14

What is the main adaptive advantage of CAM photosynthesis?

Accepted Answer

It allows plants to conserve water by opening stomata at night

Question 15

Which of the following statements about the energy of photons is correct?

Accepted Answer

Shorter wavelength photons have more energy than longer wavelength photons

Question 16

A plant is exposed to light that is only green in wavelength. What is the most likely outcome for its rate of photosynthesis?

Accepted Answer

It will decrease because chlorophyll reflects green light

Question 17

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

Accepted Answer

They broaden the spectrum of light that can drive photosynthesis and provide photoprotection

Question 18

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

Accepted Answer

Three

Question 19

Which of the following is true about the products of the Calvin cycle?

Accepted Answer

G3P can be used to synthesize glucose and other carbohydrates

Question 20

Which process in photosynthesis is most directly responsible for the release of oxygen gas?

Accepted Answer

The splitting of water during the light reactions

Photosynthesis: Mechanisms, Pigments, and Adaptations

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