Photosynthesis (Grade 9 Life Sciences)
What is Photosynthesis?
Photosynthesis is the process by which green plants make their own food (glucose) using sunlight,
carbon dioxide, and water. This process takes place mainly in the leaves of plants.
Why photosynthesis is important: - It produces food (glucose) for plants - It releases oxygen, which living
organisms need to breathe - It is the base of most food chains on Earth
Raw Materials Needed
Plants need the following for photosynthesis: - Sunlight – provides energy - Carbon dioxide (CO₂) – enters
the leaf through stomata - Water (H₂O) – absorbed by roots and transported by xylem - Chlorophyll –
green pigment that traps light energy
Where Does Photosynthesis Happen?
Photosynthesis occurs in the chloroplasts of plant cells. - Chloroplasts contain chlorophyll - Chlorophyll
absorbs light energy from the sun
Diagram: Chloroplast (Labelled)
Draw or include a simple diagram of a chloroplast and label the following parts: - Outer membrane -
Inner membrane - Grana (stacks of thylakoids) - Thylakoids (where light reactions happen) - Stroma (fluid
where glucose is formed)
Exam tip: Light energy is trapped in the thylakoids, while glucose is made in the stroma.
The Word Equation for Photosynthesis
Carbon dioxide + Water → Glucose + Oxygen
(With sunlight and chlorophyll)
The Chemical Equation
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
1
What is Photosynthesis?
Photosynthesis is the process by which green plants make their own food (glucose) using sunlight,
carbon dioxide, and water. This process takes place mainly in the leaves of plants.
Why photosynthesis is important: - It produces food (glucose) for plants - It releases oxygen, which living
organisms need to breathe - It is the base of most food chains on Earth
Raw Materials Needed
Plants need the following for photosynthesis: - Sunlight – provides energy - Carbon dioxide (CO₂) – enters
the leaf through stomata - Water (H₂O) – absorbed by roots and transported by xylem - Chlorophyll –
green pigment that traps light energy
Where Does Photosynthesis Happen?
Photosynthesis occurs in the chloroplasts of plant cells. - Chloroplasts contain chlorophyll - Chlorophyll
absorbs light energy from the sun
Diagram: Chloroplast (Labelled)
Draw or include a simple diagram of a chloroplast and label the following parts: - Outer membrane -
Inner membrane - Grana (stacks of thylakoids) - Thylakoids (where light reactions happen) - Stroma (fluid
where glucose is formed)
Exam tip: Light energy is trapped in the thylakoids, while glucose is made in the stroma.
The Word Equation for Photosynthesis
Carbon dioxide + Water → Glucose + Oxygen
(With sunlight and chlorophyll)
The Chemical Equation
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
1
