Read Photosynthesis: Follow Inputs, Products and Transport
Photosynthesis uses carbon dioxide and water to make carbohydrates, releasing oxygen. The question is usually solved by tracking where each substance enters or leaves.
Photosynthesis uses light energy to make food in green plant cells; transport tissues move water and sugar where they are needed.
Track what enters, leaves and moves inside
H₂O rises from roots in xylem · sugar travels from the leaf in phloem
CO₂ enters through stomata; water arrives from roots; oxygen leaves the leaf. Sugar is transported from the source leaf to use or storage sites.
Map each material
Carbon dioxide enters leaves through stomata. Water is absorbed by roots and carried upward in xylem. Oxygen diffuses out, while sugar made in leaves is transported to sinks through phloem.
Check direction before naming tissue
Xylem mainly carries water and minerals from roots upward. Phloem carries food from a source such as a leaf to places of use or storage; this movement need not be only upward.
OlympIQ exam lens
- ✓Identify the gas taken in and the gas released.
- ✓Separate water movement from food movement.
- ✓Use stomata, roots, xylem and phloem precisely.
Oxygen is a product of photosynthesis but is also used in respiration. The process named in the question decides which role matters.
Ready to try the pattern?
100% coverage across the linked question.
Practise the linked question