Question 1

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

Accepted Answer

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

Question 2

During the light reactions of photosynthesis, which molecule acts as the final electron acceptor?

Accepted Answer

NADP$^+$

Question 3

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

Accepted Answer

Thylakoid membrane

Question 4

What is the main product of the Calvin cycle that is used to synthesize glucose and other sugars?

Accepted Answer

Glyceraldehyde 3-phosphate (G3P)

Question 5

Which enzyme is responsible for carbon fixation in the Calvin cycle?

Accepted Answer

Rubisco

Question 6

How does chemiosmosis in chloroplasts differ from that in mitochondria?

Accepted Answer

Protons are pumped into the thylakoid space in chloroplasts, but into the intermembrane space in mitochondria.

Question 7

Which pigment is primarily responsible for absorbing light energy in photosynthesis?

Accepted Answer

Chlorophyll a

Question 8

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 reflects green light.

Question 9

Which of the following statements about autotrophs and heterotrophs is correct?

Accepted Answer

Autotrophs produce their own organic molecules from inorganic sources, while heterotrophs rely on consuming other organisms.

Question 10

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

Accepted Answer

Splitting of water during the light reactions

Question 11

A mutation disables the ATP synthase in a plant’s chloroplasts. Which process would be most directly affected?

Accepted Answer

Photophosphorylation

Question 12

Which of the following is a correct comparison between the Calvin cycle and the citric acid cycle?

Accepted Answer

The Calvin cycle is anabolic and consumes ATP and NADPH, while the citric acid cycle is catabolic and produces ATP and NADH.

Question 13

Which of the following best explains why leaves appear green?

Accepted Answer

Chlorophyll absorbs violet-blue and red light, but reflects and transmits green light.

Question 14

In a scenario where a plant’s stomata are blocked, which process would be most directly affected?

Accepted Answer

Gas exchange of CO$_2$ and O$_2$

Question 15

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

Accepted Answer

Glucose

Question 16

A scientist measures the rate of photosynthesis in a plant and finds it is highest under red and blue light. What does this suggest about the plant’s pigments?

Accepted Answer

The plant’s pigments absorb red and blue light most efficiently.

Question 17

Which molecule is regenerated during the Calvin cycle to allow the cycle to continue?

Accepted Answer

RuBP (ribulose bisphosphate)

Question 18

If a plant’s chloroplasts are unable to produce NADPH, which stage of photosynthesis would be most directly affected?

Accepted Answer

Reduction phase of the Calvin cycle

Question 19

Which of the following is a real-world consequence of photosynthesis for life on Earth?

Accepted Answer

It produces the oxygen in the atmosphere that most organisms need for cellular respiration.

Question 20

A plant cell is placed in an environment with no light but with abundant CO$_2$ and water. Which process will be most directly inhibited?

Accepted Answer

Light reactions

Photosynthesis: Structure, Function, and Key Concepts (Campbell Biology in Focus, Chapter 8)

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