Starter quiz
- What is the main function of chloroplasts in plant cells?
- to carry out photosynthesis ✓
- to provide structural support
- to store genetic information
- to transport water
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- Which gas is essential for photosynthesis?
- carbon dioxide (CO₂) ✓
- hydrogen (H₂)
- nitrogen (N₂)
- oxygen (O₂)
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- What is the chemical formula for glucose?
- C₁₂H₂₂O₁₁
- C₆H₁₂O₆ ✓
- CO₂
- H₂O
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- Which part of the plant leaf contains the most chloroplasts?
- the cuticle
- the palisade mesophyll ✓
- the spongy mesophyll
- the stomata
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- How does carbon dioxide enter the plant leaves?
- through the cuticle
- through the roots
- through the stomata ✓
- through the veins
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- What is the main product of photosynthesis?
- carbon dioxide
- glucose ✓
- oxygen
- water
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Exit quiz
- What does it mean when a factor is described as a limiting factor?
- it enhances the rate of photosynthesis when in short supply
- it has no effect on photosynthesis
- it slows down or limits the rate of photosynthesis when in short supply ✓
- it stops the process of photosynthesis
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- Which of the following are not limiting factors of photosynthesis?
- oxygen concentration ✓
- carbon dioxide concentration
- light intensity
- chlorophyll availability
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What occurs when light intensity reaches optimum levels in photosynthesis?- the rate of photosynthesis decreases
- photosynthesis stops completely
- the rate of photosynthesis no longer increases ✓
- the rate of photosynthesis increases indefinitely
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What is the relationship between temperature and the rate of photosynthesis?- temperature has no effect on the rate of photosynthesis
- the rate decreases with temperature
- the rate increases with temperature until enzymes denature ✓
- the rate remains constant with temperature changes
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Which of the following is most likely to be limiting the rate of photosynthesis at point A of the graph?- light intensity
- carbon dioxide concentration ✓
- oxygen concentration
- temperature
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Which of the following can be concluded from this graph?- the rate is limited by CO₂ concentration ✓
- the rate is limited by light intensity
- the rate is limited by temperature ✓
- CO₂ concentration has a greater effect on the rate than temperature ✓
- the rate is unaffected by CO₂ concentration
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Rate of photosynthesis increases as CO₂ concentration, temperature and light intensity increase from low levels.
- The rate of photosynthesis can be limited by one of these factors even if the others continue to increase.
- The rate of photosynthesis increases until one of more factors becomes limiting, then does not increase further.
- Interpretation and explanation of graphs depicting effect of interacting limiting factors on the rate of photosynthesis.
Common misconception
Failing to realise that the plateau on a rate graph can occur because another factor (not named on the axes) has become limiting.
The lesson explores rate graphs in which multiple limiting factors are affecting the rate of photosynthesis.
Keywords
Photosynthesis - The process used by producers to make their own food via a series of chemical reactions.
Rate - A measure of how much change occurs per unit of time.
Limiting factor - A condition that, when in short supply, slows down or limits the rate of photosynthesis.
Enzyme - A biological catalyst that speeds up a chemical reaction without itself being used up.
Optimum - The conditions where maximum rate of reaction occurs.
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