Photosynthesis: Light and Dark Reactions - Advanced Concepts
Q. How does the concentration of carbon dioxide affect the rate of photosynthesis?
-
A.
Increases rate
-
B.
Decreases rate
-
C.
No effect
-
D.
Only affects light reactions
Solution
Increasing the concentration of carbon dioxide generally increases the rate of photosynthesis up to a certain point.
Correct Answer: A — Increases rate
Q. In which part of the chloroplast do the light reactions occur?
-
A.
Stroma
-
B.
Thylakoid membranes
-
C.
Outer membrane
-
D.
Inner membrane
Solution
The light reactions of photosynthesis occur in the thylakoid membranes of the chloroplast.
Correct Answer: B — Thylakoid membranes
Q. In which part of the chloroplast do the light-dependent reactions occur?
-
A.
Stroma
-
B.
Thylakoid membranes
-
C.
Outer membrane
-
D.
Inner membrane
Solution
The light-dependent reactions occur in the thylakoid membranes of the chloroplast.
Correct Answer: B — Thylakoid membranes
Q. What is photolysis in the context of photosynthesis?
-
A.
Splitting of water molecules
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B.
Formation of glucose
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C.
Absorption of light
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D.
Release of oxygen
Solution
Photolysis refers to the splitting of water molecules during the light-dependent reactions.
Correct Answer: A — Splitting of water molecules
Q. What is produced as a byproduct of the light-dependent reactions of photosynthesis?
-
A.
Glucose
-
B.
Oxygen
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C.
NADPH
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D.
ATP
Solution
Oxygen is produced as a byproduct of the light-dependent reactions.
Correct Answer: B — Oxygen
Q. What is produced during the light-dependent reactions of photosynthesis?
-
A.
Glucose
-
B.
Oxygen
-
C.
NADPH
-
D.
Both B and C
Solution
Oxygen and NADPH are produced during the light-dependent reactions.
Correct Answer: D — Both B and C
Q. What is the main purpose of the Calvin cycle in photosynthesis?
-
A.
To produce ATP
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B.
To fix carbon dioxide
-
C.
To generate oxygen
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D.
To absorb light energy
Solution
The main purpose of the Calvin cycle is to fix carbon dioxide into organic molecules.
Correct Answer: B — To fix carbon dioxide
Q. What is the primary pigment involved in photosynthesis that absorbs light energy?
-
A.
Chlorophyll a
-
B.
Carotenoids
-
C.
Xanthophylls
-
D.
Chlorophyll b
Solution
Chlorophyll a is the main pigment that absorbs light energy for photosynthesis.
Correct Answer: A — Chlorophyll a
Q. What is the role of ATP and NADPH in the Calvin cycle?
-
A.
Energy and reducing power
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B.
Oxygen production
-
C.
Carbon fixation
-
D.
Light absorption
Solution
ATP provides energy and NADPH provides reducing power for the Calvin cycle.
Correct Answer: A — Energy and reducing power
Q. What is the role of ATP in the light-independent reactions?
-
A.
Energy source
-
B.
Electron carrier
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C.
Carbon source
-
D.
None of the above
Solution
ATP serves as the energy source for the light-independent reactions (Calvin cycle).
Correct Answer: A — Energy source
Q. What is the role of NADPH in photosynthesis?
-
A.
Energy storage
-
B.
Electron transport
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C.
Carbon fixation
-
D.
Light absorption
Solution
NADPH serves as an electron carrier in the light-independent reactions of photosynthesis.
Correct Answer: B — Electron transport
Q. What is the significance of the Z-scheme in photosynthesis?
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A.
It describes the Calvin cycle
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B.
It illustrates electron transport
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C.
It shows light absorption
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D.
It explains water splitting
Solution
The Z-scheme illustrates the flow of electrons through the photosystems during light reactions.
Correct Answer: B — It illustrates electron transport
Q. Which enzyme catalyzes the first step of the Calvin cycle?
-
A.
Rubisco
-
B.
ATP synthase
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C.
NADP+ reductase
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D.
Phosphofructokinase
Solution
Rubisco catalyzes the first step of the Calvin cycle by fixing carbon dioxide.
Correct Answer: A — Rubisco
Q. Which factor does NOT affect the rate of photosynthesis?
-
A.
Light intensity
-
B.
Carbon dioxide concentration
-
C.
Soil pH
-
D.
Temperature
Solution
Soil pH does not directly affect the rate of photosynthesis.
Correct Answer: C — Soil pH
Q. Which factor does NOT directly affect the rate of photosynthesis?
-
A.
Light intensity
-
B.
Temperature
-
C.
Soil pH
-
D.
Carbon dioxide concentration
Solution
Soil pH does not directly affect the rate of photosynthesis; it affects plant health indirectly.
Correct Answer: C — Soil pH
Q. Which molecule acts as the primary electron donor in the light reactions?
-
A.
Water
-
B.
NADP+
-
C.
Glucose
-
D.
RuBP
Solution
Water acts as the primary electron donor in the light reactions, providing electrons.
Correct Answer: A — Water
Q. Which of the following factors can limit the rate of photosynthesis?
-
A.
Light intensity
-
B.
Carbon dioxide concentration
-
C.
Temperature
-
D.
All of the above
Solution
All of the above factors can limit the rate of photosynthesis.
Correct Answer: D — All of the above
Q. Which of the following is a product of the light reactions that is used in the Calvin cycle?
-
A.
Oxygen
-
B.
Glucose
-
C.
NADPH
-
D.
Carbon dioxide
Solution
NADPH is a product of the light reactions that is used in the Calvin cycle.
Correct Answer: C — NADPH
Q. Which of the following is a product of the light-dependent reactions that is used in the Calvin cycle?
-
A.
Oxygen
-
B.
NADPH
-
C.
Glucose
-
D.
RuBP
Solution
NADPH is a product of the light-dependent reactions that is used in the Calvin cycle.
Correct Answer: B — NADPH
Q. Which of the following is NOT a product of the light reactions?
-
A.
ATP
-
B.
NADPH
-
C.
Glucose
-
D.
Oxygen
Solution
Glucose is not produced during the light reactions; it is synthesized in the Calvin cycle.
Correct Answer: C — Glucose
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