A-LevelBiology

A-Level Biology Photosynthesis Revision Notes

Master A-Level Biology Photosynthesis using simple revision notes, key facts and practice questions — all generated by AI for your exam.

Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. This process takes place mainly in the chloroplasts of plant cells and involves two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle).

Key Concepts

  • 1Photosynthesis occurs in chloroplasts, primarily in the leaves of plants.
  • 2The overall equation for photosynthesis is 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.
  • 3Light-dependent reactions convert light energy into chemical energy in the form of ATP and NADPH.
  • 4Light-independent reactions (Calvin cycle) use ATP and NADPH to convert CO2 into glucose.
  • 5Factors affecting the rate of photosynthesis include light intensity, carbon dioxide concentration, and temperature.

Simple Explanation

Photosynthesis is how plants make their food using sunlight. They take in carbon dioxide from the air and water from the soil, and with the help of sunlight, they turn these into glucose, which is a type of sugar. Oxygen is released as a byproduct. This process is essential for life on Earth as it provides food and oxygen.

Memory Trick

“Remember 'COWS' for Photosynthesis: Carbon dioxide, Oxygen, Water, Sunlight.”

Flashcards

Question1 / 5

What is the main pigment involved in photosynthesis?

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Exam Questions

Describe and explain the light-dependent reactions of photosynthesis. [6 marks]

6 marks
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Include details about the role of chlorophyll, the production of ATP and NADPH, and the photolysis of water.

Explain how temperature affects the rate of photosynthesis. [4 marks]

4 marks
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Discuss the effect of temperature on enzyme activity and the overall rate of photosynthesis.

What is meant by the term 'Calvin cycle'? [2 marks]

2 marks
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Define the Calvin cycle and its role in photosynthesis.

Practice Quiz

Question 1 of 5Score: 0

What is the main function of chlorophyll in photosynthesis?

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