Photosynthesis: How Plants Make Food

Grade 6 · Science · Study Guide

Plants are the original solar-powered machines. Through photosynthesis, they capture sunlight and convert it into glucose, a sugar they use for energy. This process happens mainly in the leaves, inside tiny structures called chloroplasts that contain a green pigment called chlorophyll. That chlorophyll is why most plants look green.

Here's the recipe: plants take in carbon dioxide (CO2) from the air through tiny pores called stomata, absorb water (H2O) from the soil through their roots, and use sunlight energy to combine them. The result? Glucose (C6H12O6) for food and oxygen (O2) as a byproduct that gets released into the air. Yes, the oxygen you're breathing right now was made by a plant doing photosynthesis.

Without photosynthesis, life on Earth as we know it couldn't exist. Plants sit at the base of almost every food chain. They feed the herbivores, which feed the carnivores, which feed everything else. And they keep our atmosphere breathable by producing the oxygen we need.

Key terms

Photosynthesis
The process plants use to convert sunlight, water, and carbon dioxide into glucose and oxygen.
Chloroplast
The organelle inside plant cells where photosynthesis takes place.
Chlorophyll
The green pigment in chloroplasts that absorbs sunlight energy.
Stomata
Tiny pores on the surface of leaves that let carbon dioxide in and oxygen out.
Glucose
A simple sugar that plants produce during photosynthesis and use as food energy.
Carbon Dioxide
A gas (CO2) that plants absorb from the air as a raw material for photosynthesis.

Flashcards

Photosynthesis
Sunlight + water + CO2 turned into glucose and oxygen by plants.
Chloroplast
The organelle (tiny factory) inside plant cells where photosynthesis happens.
Chlorophyll
Green pigment that absorbs sunlight. It's why plants are green.
Stomata
Tiny pores on leaves that let CO2 in and O2 out.
Glucose
The sugar plants make as food during photosynthesis (C6H12O6).
Carbon Dioxide (CO2)
The gas from the air that plants use as a raw ingredient.

Questions

  1. Where does photosynthesis mainly take place in a plant?

    1. Roots
    2. Stem
    3. Leaves
    4. Flowers
    Show answer

    Answer: Leaves

    Leaves contain the most chloroplasts, making them the main site of photosynthesis. Their flat shape maximizes sun exposure.

  2. What are the THREE things a plant needs for photosynthesis?

    1. Oxygen, water, and soil
    2. Sunlight, water, and carbon dioxide
    3. Sunlight, oxygen, and minerals
    4. Carbon dioxide, soil, and heat
    Show answer

    Answer: Sunlight, water, and carbon dioxide

    The photosynthesis equation: Sunlight + Water + Carbon Dioxide → Glucose + Oxygen. Soil provides minerals but isn't directly part of the reaction.

  3. The green pigment that captures sunlight in plant cells is called ___.

    Show answer

    Answer: chlorophyll

    Chlorophyll is the green pigment found inside chloroplasts. It absorbs red and blue light, reflecting green, which is why plants look green.

  4. Oxygen is a byproduct of photosynthesis that plants release into the air.

    Show answer

    Answer: True

    Plants produce oxygen as a waste product of splitting water molecules during photosynthesis. This is the primary source of oxygen in Earth's atmosphere.

  5. What gas enters the leaf through the stomata for photosynthesis?

    1. Oxygen
    2. Nitrogen
    3. Carbon dioxide
    4. Hydrogen
    Show answer

    Answer: Carbon dioxide

    Carbon dioxide (CO2) enters through the stomata. The plant uses the carbon to build glucose molecules.

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