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The process of photosynthesis is fundamental to life on Earth. It is the method by which green plants, algae, and some bacteria convert sunlight into chemical energy. Using sunlight, these organisms transform carbon dioxide and water into glucose and oxygen. The glucose serves as food, providing energy and building materials for growth, while oxygen is released into the atmosphere.
Photosynthesis occurs mainly in the leaves of plants, within tiny structures called chloroplasts. Chlorophyll, the green pigment inside chloroplasts, captures sunlight. The process can be divided into two stages: the light-dependent reactions and the light-independent reactions, also known as the Calvin cycle.
In the light-dependent reactions, sunlight is absorbed and converted into chemical energy in the form of ATP and NADPH. During the Calvin cycle, this chemical energy is used to fix carbon dioxide and produce glucose. Photosynthesis not only sustains the plant but also maintains the balance of oxygen and carbon dioxide in the atmosphere, supporting life for all aerobic organisms.
Questions (1 mark each):
Comprehension (6 marks)
1. What is photosynthesis?
b) Conversion of sunlight into chemical energy
c) Breathing process
d) Digestion in animals
2. Which organisms perform photosynthesis?
b) Green plants, algae, some bacteria
c) Fungi
d) All living beings
3. What are the main products of photosynthesis?
b) Carbon dioxide and water
c) ATP and NADPH
d) Chlorophyll and sunlight
4. Where does photosynthesis mainly take place?
b) Stems
c) Leaves
d) Flowers
5. What is chlorophyll?
b) A type of bacteria
c) A kind of sugar
d) A gas released by plants
6. What are the two stages of photosynthesis?
b) Light-dependent reactions and Calvin cycle
c) Photosynthesis and transpiration
d) Light absorption and chlorophyll creation
Grammar (5 marks)
7. Identify the tense: Plants convert carbon dioxide into glucose.
b) Past simple
c) Present continuous
d) Past perfect
8. Choose the correct passive voice: Chlorophyll captures sunlight.
b) Chlorophyll is captured by sunlight.
c) Sunlight captures chlorophyll.
d) Chlorophyll captured sunlight.
9. Pick the correct conjunction: Photosynthesis produces glucose and oxygen.
b) glucose
c) and
d) oxygen
10. Identify the pronoun: It provides energy and building materials.
b) provides
c) energy
d) materials
11. Choose the correct preposition: Photosynthesis occurs ___ the leaves.
b) in
c) at
d) by
Vocabulary (4 marks)
12. What does “chemical energy” mean?
b) Energy from the sun
c) Energy produced by movement
d) Heat energy
13. What is the meaning of “fix carbon dioxide”?
b) Convert carbon dioxide into organic molecules
c) Destroy carbon dioxide
d) Produce carbon dioxide
14. What does “aerobic” mean?
b) With oxygen
c) Related to plants
d) Related to animals
15. What does “sustain” mean?
b) To support or maintain
c) To reduce
d) To ignore
✅ Answer Key:
b) Conversion of sunlight into chemical energy
b) Green plants, algae, some bacteria
a) Oxygen and glucose
c) Leaves
a) A pigment that captures sunlight
b) Light-dependent reactions and Calvin cycle
a) Present simple
a) Sunlight is captured by chlorophyll.
c) and
a) It
b) in
a) Energy stored in food molecules
b) Convert carbon dioxide into organic molecules
b) With oxygen
b) To support or maintain
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