How Plants Make Food

A free interactive lesson on nutrition in plants — how photosynthesis turns CO₂, water, and sunlight into glucose and oxygen. Covers chloroplasts and chlorophyll. Based on NCERT Class 6 Living Creatures chapter. Includes a quick quiz.

Class 6 ScienceClass 6 / Grade 6Ages 8–11
Lesson
🌿 How Plants Make Food
Plants make their own food. How?Sunlight+CO₂Carbon dioxide+H₂OWater (roots)

You and I need to eat food. But plants never eat a meal — they make their own food using sunlight, water from the soil, and carbon dioxide from the air. This process is called photosynthesis, and it's one of the most important reactions on Earth.

How do plants get their food?

Unlike animals, plants do not eat food — they make it. This process is called photosynthesis. Plants are called autotrophs (self-feeders) because of this ability. All other organisms that eat plants or animals are heterotrophs — they depend on autotrophs as the ultimate source of all food.

The photosynthesis equation

Photosynthesis combines three inputs to produce two outputs:

CO₂ + H₂O + Sunlight → Glucose (C₆H₁₂O₆) + O₂

  • Carbon dioxide (CO₂) — absorbed from air through tiny pores in leaves called stomata.
  • Water (H₂O) — absorbed from the soil through roots and transported up the stem.
  • Sunlight — captured by chlorophyll in the chloroplasts.
  • Glucose — the plant's food, stored as starch or used for energy.
  • Oxygen (O₂) — released into the air as a by-product. This is the oxygen we breathe.

Chlorophyll — the green pigment

Inside chloroplasts is a green pigment called chlorophyll. Chlorophyll absorbs red and blue light from sunlight and uses their energy to drive photosynthesis. It reflects green light — which is why we see leaves as green.

In autumn, as days shorten, chlorophyll breaks down. The hidden yellow and red pigments (which were always there but masked) become visible — giving us autumn colours.

Where does photosynthesis happen?

Photosynthesis happens in chloroplasts — small green structures inside plant cells, mostly in the leaves. A single leaf cell may contain 50 chloroplasts. Each chloroplast is packed with stacks of membranes called thylakoids where the light reactions happen.

Frequently asked questions

What is photosynthesis?

Photosynthesis is the process by which green plants make their own food using carbon dioxide, water, and sunlight. It produces glucose (food) and releases oxygen as a by-product.

Why are leaves green?

Because of chlorophyll. Chlorophyll absorbs red and blue light and reflects green light. The reflected green light reaches our eyes, making leaves appear green.

Where does photosynthesis take place?

In chloroplasts — green structures inside plant cells, mainly in the leaves. Chloroplasts contain chlorophyll, the pigment that captures sunlight.

What is the by-product of photosynthesis?

Oxygen (O₂). When plants make glucose from CO₂ and H₂O, they release oxygen as a waste product — which is the oxygen all animals breathe.

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