This section focuses on the practical and applied aspects of the light and dark reactions of photosynthesis and how these processes influence plant productivity, agriculture, and environmental sustainability. It is suitable for Class 11–12 students , NEET aspirants , and undergraduate learners who want to understand how photosynthetic mechanisms are applied beyond theory.
In this section, you will study:
Relationship between light and dark reactions in crop productivity
Role of photosynthesis in agricultural yield improvement
Application of C3, C4, and CAM pathways in plant adaptation
Manipulation of light intensity, CO₂ concentration, and temperature in agriculture
Use of photosynthesis principles in greenhouse and controlled environment farming
Impact of photosynthetic efficiency on global carbon cycle and climate regulation
NCERT-based application questions, case studies, and exam-oriented problems
The content is designed to improve application-based thinking , strengthen real-world problem-solving , and help students confidently handle assertion–reason, case-based, and higher-order questions in school exams, NEET, and undergraduate assessments .
Understand how the principles of light and dark reactions translate into real-world applications in agriculture and environmental science.
Q. How does the availability of light affect the rate of photosynthesis?
A.
It has no effect
B.
Increases the rate until a saturation point
C.
Decreases the rate
D.
Only affects the dark reactions
Show solution
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
Learn More →
Q. In which part of the chloroplast does the Calvin cycle occur?
A.
Thylakoid membranes
B.
Outer membrane
C.
Stroma
D.
Inner membrane
Show solution
Solution
The Calvin cycle occurs in the stroma of the chloroplast.
Correct Answer:
C
— Stroma
Learn More →
Q. What is produced as a byproduct of the light reactions?
A.
Glucose
B.
Oxygen
C.
NADPH
D.
ATP
Show solution
Solution
Oxygen is released as a byproduct of the light reactions during the splitting of water.
Correct Answer:
B
— Oxygen
Learn More →
Q. What is the main product of the Calvin cycle?
A.
Oxygen
B.
ATP
C.
Glucose
D.
NADPH
Show solution
Solution
The main product of the Calvin cycle is glucose, which is synthesized from carbon dioxide.
Correct Answer:
C
— Glucose
Learn More →
Q. What is the main purpose of the dark reactions (Calvin cycle) in photosynthesis?
A.
To capture light energy
B.
To produce ATP
C.
To fix carbon dioxide into organic molecules
D.
To release oxygen
Show solution
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
Learn More →
Q. What is the primary function of the light reactions in photosynthesis?
A.
To produce glucose
B.
To convert solar energy into chemical energy
C.
To fix carbon dioxide
D.
To release oxygen
Show solution
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
Learn More →
Q. What is the role of chlorophyll in photosynthesis?
A.
To absorb water
B.
To capture light energy
C.
To synthesize glucose
D.
To release oxygen
Show solution
Solution
Chlorophyll captures light energy, which is essential for the light reactions of photosynthesis.
Correct Answer:
B
— To capture light energy
Learn More →
Q. What is the role of RuBisCO in the Calvin cycle?
A.
To produce ATP
B.
To fix carbon dioxide
C.
To generate NADPH
D.
To release oxygen
Show solution
Solution
RuBisCO is the enzyme that catalyzes the fixation of carbon dioxide in the Calvin cycle.
Correct Answer:
B
— To fix carbon dioxide
Learn More →
Q. What is the significance of the light-dependent reactions for the dark reactions?
A.
They provide glucose
B.
They produce ATP and NADPH
C.
They release carbon dioxide
D.
They absorb water
Show solution
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
Learn More →
Q. What is the significance of the light-dependent reactions in photosynthesis?
A.
They produce glucose directly
B.
They generate ATP and NADPH for the Calvin cycle
C.
They fix carbon dioxide
D.
They release carbon dioxide
Show solution
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
Learn More →
Q. What role does NADPH play in photosynthesis?
A.
It stores energy
B.
It acts as an electron donor
C.
It is a byproduct
D.
It helps in water splitting
Show solution
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
Learn More →
Q. Where do the light reactions of photosynthesis occur?
A.
In the stroma
B.
In the thylakoid membranes
C.
In the cytoplasm
D.
In the mitochondria
Show solution
Solution
The light reactions take place in the thylakoid membranes of chloroplasts.
Correct Answer:
B
— In the thylakoid membranes
Learn More →
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
Show solution
Solution
The light reactions occur in the thylakoid membranes of chloroplasts.
Correct Answer:
B
— In the thylakoid membranes
Learn More →
Q. Which enzyme is crucial for carbon fixation in the Calvin cycle?
A.
Rubisco
B.
ATP synthase
C.
NADP+ reductase
D.
Phosphofructokinase
Show solution
Solution
Rubisco is the enzyme that catalyzes the first step of carbon fixation in the Calvin cycle.
Correct Answer:
A
— Rubisco
Learn More →
Q. Which factor can limit the efficiency of photosynthesis in plants?
A.
Temperature
B.
Water availability
C.
Carbon dioxide concentration
D.
All of the above
Show solution
Solution
All of these factors can limit the efficiency of photosynthesis in plants.
Correct Answer:
D
— All of the above
Learn More →
Q. Which molecule is produced as a byproduct of the light reactions?
A.
Glucose
B.
Oxygen
C.
NADPH
D.
ATP
Show solution
Solution
Oxygen is released as a byproduct during the light reactions of photosynthesis.
Correct Answer:
B
— Oxygen
Learn More →
Q. Which molecule is produced during the light reactions and used in the Calvin cycle?
A.
Oxygen
B.
Glucose
C.
NADPH
D.
Carbon dioxide
Show solution
Solution
NADPH is produced during the light reactions and is used in the Calvin cycle for carbon fixation.
Correct Answer:
C
— NADPH
Learn More →
Q. Which pigment is primarily responsible for capturing light energy during the light reactions?
A.
Chlorophyll a
B.
Carotenoids
C.
Xanthophylls
D.
Chlorophyll b
Show solution
Solution
Chlorophyll a is the main pigment that captures light energy for photosynthesis.
Correct Answer:
A
— Chlorophyll a
Learn More →
Q. Which pigment is primarily responsible for capturing light energy in plants?
A.
Chlorophyll a
B.
Carotenoids
C.
Xanthophylls
D.
Chlorophyll b
Show solution
Solution
Chlorophyll a is the primary pigment that captures light energy for photosynthesis.
Correct Answer:
A
— Chlorophyll a
Learn More →
Showing 1 to 19 of 19 (1 Pages)
