Photosynthesis Diagram
Free printable photosynthesis diagram — a labeled illustration showing how a plant uses sunlight, water and carbon dioxide to make glucose and release oxygen. Download PDF or PNG for Letter paper.
The ingredients and products of photosynthesis
Photosynthesis is how green plants make their own food, using sunlight, water and carbon dioxide. Here is what happens at each labeled part of the diagram:
| Part | What it does | Why it matters |
|---|---|---|
| Sunlight | The energy the leaf captures to power photosynthesis. | Light is the original power source for the whole reaction — without it, the plant has no energy to convert air and water into food. On a cloudy winter day, plants slow down dramatically, which is why houseplants near dim windows grow so much more slowly than ones on a bright sill. |
| Carbon dioxide | A gas the plant takes in from the air. | Every sugar molecule a plant builds contains carbon atoms that came straight from the air, making plants literal living filters of the atmosphere. If plants stopped absorbing carbon dioxide, the gas would continue to build up from burning fuel and breathing, warming the planet even faster than it does today. |
| Water | Absorbed by the roots and carried up to the leaves. | A plant can lose its leaves and regrow them, but if its roots dry out completely, it dies — because without water, photosynthesis simply stops. The hydrogen atoms locked inside each water molecule end up woven into the glucose the plant produces, so every bite of fruit or vegetable you eat contains atoms that were once water in the soil. |
| Glucose | The sugar (food) the plant makes and uses for energy and growth. | Glucose is the finished product — the sugar that fuels every cell in the plant's body, from growing new roots to producing flowers and seeds. When you eat a potato, a carrot, or a grain of rice, you are consuming stored glucose that a plant built from sunlight, water, and air. |
| Oxygen | A gas the plant releases into the air as a by-product. | Released as a by-product the plant doesn't even need, oxygen is essentially waste — yet it is the gas that all animals, including humans, depend on to breathe. Scientists believe that almost all of the oxygen in Earth's atmosphere was put there by billions of years of photosynthesis, meaning every breath you have ever taken was a gift from a plant. |
Companion worksheet
A free fill-in worksheet with an answer key, built from the labels above — students match each part to its description, then answer a couple of short questions. Great for a quick check after using the diagram.
How to print
Choose Download PDF for a ready-to-print file that fits US Letter paper (8.5 × 11") in landscape, or Download PNG for the high-resolution image.
Frequently asked questions
What is photosynthesis?
Photosynthesis is the process green plants use to turn sunlight, water and carbon dioxide into glucose (their food), releasing oxygen as a by-product.
What does a plant need for photosynthesis?
A plant needs sunlight, water and carbon dioxide. It uses these to make glucose and gives off oxygen.
What paper size should I print this on?
The diagram is sized for standard US Letter paper (8.5 × 11") in landscape orientation. Use "Download PDF" for a print-ready file that fits the page automatically.