Uses of glucose from photosynthesis
Laura Armstrong & Joe Wolfensohn
Teachers
Contents
Recall Questions
This topic requires prior knowledge of photosynthesis.
What is the word equation for photosynthesis?
Carbon dioxide + water → glucose + oxygen (in the presence of light and chlorophyll).
Which pigment absorbs light for photosynthesis?
Chlorophyll.
In which tissue in the leaf does most photosynthesis take place?
The palisade mesophyll tissue.
Topic Explainer Videos
Check out these @JoeDoesBiology and @lauradoesbiology videos that explain the uses of glucose from photosynthesis, then read the study notes. Once you’ve gone through them, don’t forget to try the practice questions!
What Happens to the Glucose?
The glucose made during photosynthesis is not just used for energy. Plants use it in five different ways, and you can remember them using the acronym SCARF:
S – Starch (Storage)
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Glucose is converted into insoluble starch and stored in roots, stems, or leaves.
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This starch can be broken back down into glucose and used when photosynthesis isn't happening, e.g. at night when no light energy is available.
C – Cellulose (Structure)
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Glucose is converted into cellulose, a strong carbohydrate.
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Cellulose is used to build plant cell walls, giving structural support.
A – Amino Acids (Growth)
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Glucose is combined with nitrates from the soil to make amino acids.
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These are used to build proteins, which are essential for plant growth and repair.
R – Respiration (Energy)
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Glucose is broken down in aerobic respiration to release energy.
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This energy is used for processes like active transport, cell division, and protein synthesis.
F – Fats and Oils (Storage)
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Glucose is also converted into lipids (fats and oils).
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These are stored in seeds as an energy reserve.
Summary: SCARF
|
Letter |
Use |
Purpose |
|---|---|---|
|
S |
Starch |
Energy storage |
|
C |
Cellulose |
Cell wall structure |
|
A |
Amino acids |
Growth and protein synthesis |
|
R |
Respiration |
Energy for cell functions |
|
F |
Fats and oils |
Long-term energy store in seeds |
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Key Terms
- Glucose - A sugar made in photosynthesis.
- Starch - An insoluble storage form of glucose in plants.
- Amino acids - The building blocks of proteins, made from glucose and nitrates.
- Cellulose - A structural carbohydrate found in plant cell walls.
No answer provided.
Exam Tip
In questions about the uses of glucose in plants, structure your answer using SCARF to show clear understanding. Add why each use is important to the plant.
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Practice Question
Explain how plants use the glucose produced in photosynthesis. (5 marks)
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Glucose is converted into starch for storage, especially in roots (1).
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It is used to make cellulose, which strengthens the plant cell walls (1).
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Glucose is combined with nitrates to make amino acids for growth and protein production (1).
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It is used in respiration to release energy for cell activities like active transport (1).
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Glucose is also turned into fats and oils, which are stored in seeds (1).
More Practice
Try to answer these practice questions from the TikTok videos on your own, then watch the videos to see how well you did!