Multiple Choice Questions (MCQ) on Photosynthesis

To excel in the 20 multiple-choice (MCQ) questions on photosynthesis, carefully read each question to understand what is being asked and apply your knowledge of key concepts, such as the roles of sunlight, water, carbon dioxide, and chlorophyll, as well as the processes of light-dependent and light-independent reactions. Eliminate incorrect options to narrow down your choices, look for context clues within the question, and avoid overthinking by sticking to the basics unless deeper analysis is required. Finally, review your answers to ensure accuracy, and practice with past questions to build confidence and familiarity with the exam format. Stay focused, trust your preparation, and aim for your best performance! Check the radio buttons for each options and click submit quiz to see the answer. 

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1. What gas do plants use for photosynthesis?

A. Oxygen
B. Nitrogen
C. Carbon Dioxide
D. Hydrogen

2. What is the main product of photosynthesis?

A. Glucose
B. Oxygen
C. Carbon Dioxide
D. Water

3. Which part of the plant is mainly responsible for photosynthesis?

A. Roots
B. Leaves
C. Stem
D. Flowers

4. What pigment in plants absorbs light for photosynthesis?

A. Chlorophyll
B. Melanin
C. Hemoglobin
D. Keratin

5. What is the source of energy for photosynthesis?

A. Soil
B. Water
C. Wind
D. Sunlight

6. What are the two main products of photosynthesis?

A. Oxygen and nitrogen
B. Oxygen and glucose
C. Water and carbon dioxide
D. Glucose and protein

7. In which cell structure does photosynthesis occur?

A. Mitochondria
B. Nucleus
C. Chloroplast
D. Vacuole

8. What is the role of water in photosynthesis?

A. Provides electrons and hydrogen
B. Cools the leaf
C. Absorbs sunlight
D. Forms chlorophyll

9. Which of the following is NOT required for photosynthesis?

A. Water
B. Carbon Dioxide
C. Light
D. Oxygen

10. During photosynthesis, what is released into the air?

A. Carbon Dioxide
B. Nitrogen
C. Oxygen
D. Hydrogen

11. The light-dependent reactions of photosynthesis primarily serve to ______.

A. produce glucose molecules
B. generate ATP and NADPH
C. release oxygen into the atmosphere
D. break down carbon dioxide molecules

12. In the Calvin Cycle, ATP is used as ______.

A. the primary energy carrier
B. a structural component of glucose
C. an oxygen donor
D. a carbon dioxide absorber

13. During photosynthesis, carbon dioxide is fixed into organic compounds during ______.

A. glycolysis
B. the electron transport chain
C. the Calvin Cycle
D. the light-dependent reactions

14. The enzyme Rubisco plays a critical role in photosynthesis by ______.

A. absorbing sunlight
B. splitting water molecules
C. synthesizing ATP
D. catalyzing the fixation of carbon dioxide

15. During the light-dependent reactions, electrons in chlorophyll are excited and then ______.

A. destroyed by oxygen
B. transferred to an electron transport chain
C. stored in glucose molecules
D. released into the atmosphere

16. The purpose of the electron transport chain in photosynthesis is to ______.

A. produce ATP and NADPH
B. split water molecules directly
C. fix carbon dioxide into sugars
D. absorb sunlight efficiently

17. NADPH is essential in photosynthesis because it provides ______.

A. structural support to plant cells
B. energy for splitting water molecules
C. high-energy electrons for glucose synthesis
D. oxygen for cellular respiration

18. The rate of photosynthesis can be limited by low levels of ______, which affects carbon dioxide availability.

A. soil nutrients
B. temperature
C. wind speed
D. atmospheric CO₂ concentration

19. Stomata in plant leaves are important because they allow ______.

A. glucose storage
B. gas exchange, including CO₂ intake and O₂ release
C. absorption of sunlight
D. production of ATP

20. Plants appear green because chlorophyll ______.

A. reflects green light and absorbs other wavelengths
B. absorbs green light and reflects other wavelengths
C. emits green light during photosynthesis
D. requires green light for glucose synthesis

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