Photosynthesis: Light and Dark Reactions - Applications
Q. How does the availability of light affect the rate of photosynthesis?
-
A.
It has no effect
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B.
Increases the rate until a saturation point
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C.
Decreases the rate
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D.
Only affects the dark reactions
Solution
The rate of photosynthesis increases with light availability until it reaches a saturation point.
Correct Answer: B — Increases the rate until a saturation point
Q. In which part of the chloroplast does the Calvin cycle occur?
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A.
Thylakoid membranes
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B.
Outer membrane
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C.
Stroma
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D.
Inner membrane
Solution
The Calvin cycle occurs in the stroma of the chloroplast.
Correct Answer: C — Stroma
Q. What is produced as a byproduct of the light reactions?
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A.
Glucose
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B.
Oxygen
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C.
NADPH
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D.
ATP
Solution
Oxygen is released as a byproduct of the light reactions during the splitting of water.
Correct Answer: B — Oxygen
Q. What is the main product of the Calvin cycle?
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A.
Oxygen
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B.
ATP
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C.
Glucose
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D.
NADPH
Solution
The main product of the Calvin cycle is glucose, which is synthesized from carbon dioxide.
Correct Answer: C — Glucose
Q. What is the main purpose of the dark reactions (Calvin cycle) in photosynthesis?
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A.
To capture light energy
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B.
To produce ATP
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C.
To fix carbon dioxide into organic molecules
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D.
To release oxygen
Solution
The dark reactions, or Calvin cycle, fix carbon dioxide into organic molecules like glucose.
Correct Answer: C — To fix carbon dioxide into organic molecules
Q. What is the primary function of the light reactions in photosynthesis?
-
A.
To produce glucose
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B.
To convert solar energy into chemical energy
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C.
To fix carbon dioxide
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D.
To release oxygen
Solution
The light reactions convert solar energy into chemical energy in the form of ATP and NADPH.
Correct Answer: B — To convert solar energy into chemical energy
Q. What is the role of chlorophyll in photosynthesis?
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A.
To absorb water
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B.
To capture light energy
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C.
To synthesize glucose
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D.
To release oxygen
Solution
Chlorophyll captures light energy, which is essential for the light reactions of photosynthesis.
Correct Answer: B — To capture light energy
Q. What is the role of RuBisCO in the Calvin cycle?
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A.
To produce ATP
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B.
To fix carbon dioxide
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C.
To generate NADPH
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D.
To release oxygen
Solution
RuBisCO is the enzyme that catalyzes the fixation of carbon dioxide in the Calvin cycle.
Correct Answer: B — To fix carbon dioxide
Q. What is the significance of the light-dependent reactions for the dark reactions?
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A.
They provide glucose
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B.
They produce ATP and NADPH
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C.
They release carbon dioxide
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D.
They absorb water
Solution
The light-dependent reactions produce ATP and NADPH, which are essential for the dark reactions to synthesize glucose.
Correct Answer: B — They produce ATP and NADPH
Q. What is the significance of the light-dependent reactions in photosynthesis?
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A.
They produce glucose directly
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B.
They generate ATP and NADPH for the Calvin cycle
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C.
They fix carbon dioxide
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D.
They release carbon dioxide
Solution
The light-dependent reactions generate ATP and NADPH, which are essential for the Calvin cycle.
Correct Answer: B — They generate ATP and NADPH for the Calvin cycle
Q. What role does NADPH play in photosynthesis?
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A.
It stores energy
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B.
It acts as an electron donor
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C.
It is a byproduct
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D.
It helps in water splitting
Solution
NADPH acts as an electron donor in the Calvin cycle, providing the reducing power for carbon fixation.
Correct Answer: B — It acts as an electron donor
Q. Where do the light reactions of photosynthesis occur?
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A.
In the stroma
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B.
In the thylakoid membranes
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C.
In the cytoplasm
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D.
In the mitochondria
Solution
The light reactions take place in the thylakoid membranes of chloroplasts.
Correct Answer: B — In the thylakoid membranes
Q. Where do the light reactions of photosynthesis take place?
-
A.
In the stroma
-
B.
In the thylakoid membranes
-
C.
In the cytoplasm
-
D.
In the mitochondria
Solution
The light reactions occur in the thylakoid membranes of chloroplasts.
Correct Answer: B — In the thylakoid membranes
Q. Which enzyme is crucial for carbon fixation in the Calvin cycle?
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A.
Rubisco
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B.
ATP synthase
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C.
NADP+ reductase
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D.
Phosphofructokinase
Solution
Rubisco is the enzyme that catalyzes the first step of carbon fixation in the Calvin cycle.
Correct Answer: A — Rubisco
Q. Which factor can limit the efficiency of photosynthesis in plants?
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A.
Temperature
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B.
Water availability
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C.
Carbon dioxide concentration
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D.
All of the above
Solution
All of these factors can limit the efficiency of photosynthesis in plants.
Correct Answer: D — All of the above
Q. Which molecule is produced as a byproduct of the light reactions?
-
A.
Glucose
-
B.
Oxygen
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C.
NADPH
-
D.
ATP
Solution
Oxygen is released as a byproduct during the light reactions of photosynthesis.
Correct Answer: B — Oxygen
Q. Which molecule is produced during the light reactions and used in the Calvin cycle?
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A.
Oxygen
-
B.
Glucose
-
C.
NADPH
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D.
Carbon dioxide
Solution
NADPH is produced during the light reactions and is used in the Calvin cycle for carbon fixation.
Correct Answer: C — NADPH
Q. Which pigment is primarily responsible for capturing light energy during the light reactions?
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A.
Chlorophyll a
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B.
Carotenoids
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C.
Xanthophylls
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D.
Chlorophyll b
Solution
Chlorophyll a is the main pigment that captures light energy for photosynthesis.
Correct Answer: A — Chlorophyll a
Q. Which pigment is primarily responsible for capturing light energy in plants?
-
A.
Chlorophyll a
-
B.
Carotenoids
-
C.
Xanthophylls
-
D.
Chlorophyll b
Solution
Chlorophyll a is the primary pigment that captures light energy for photosynthesis.
Correct Answer: A — Chlorophyll a
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