Photosynthesis and limiting factors
Lesson details
Learning outcome
I can explain the effects of limiting factors on the rate of photosynthesis.
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.
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.
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.
Teacher tip
Pupils can be given graphs containing multiple limiting factors to interpret for themselves or they could be given a set of different conditions and asked to sketch graphs of what they would expect the rate of photosynthesis to be in each scenario, explaining why they have drawn the graph they have.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What is the main function of chloroplasts in plant cells?
Q2.Which gas is essential for photosynthesis?
Q3.What is the chemical formula for glucose?
Q4.Which part of the plant leaf contains the most chloroplasts?
Q5.How does carbon dioxide enter the plant leaves?
Q6.What is the main product of photosynthesis?
Assessment exit quiz
6 Questions
Q1.What does it mean when a factor is described as a limiting factor?
Q2.Which of the following are not limiting factors of photosynthesis?
Q3.What occurs when light intensity reaches optimum levels in photosynthesis?
Q4.What is the relationship between temperature and the rate of photosynthesis?
Q5.Which of the following is most likely to be limiting the rate of photosynthesis at point A of the graph?
Q6.Which of the following can be concluded from this graph?
To help you plan your 11 combined science lesson on: Photosynthesis and limiting factors, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 11 combined science lesson on: Photosynthesis and limiting factors, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 combined science lessons from the Photosynthesis: factors affecting the rate unit, dive into the full secondary combined science curriculum, or learn more about lesson planning.