Photosynthesis uses energy that comes form water, the sun and carbon dioxide to make food that forms into a sugar that is called glucose.

Photosynthesis also helps to create oxygen that humans and animals use to breath.

Even though plants need food, the plants are able to provide for themselves by making the food that they need.

They are able to do this because of photosynthesis.

illustration of photosynthesis in plant

What is Needed for Photosynthesis?

Plants need three things in order to make food. The plants need sunlight, water and carbon dioxide.


Sunlight is absorbed through the leaves of a flower.


Water goes into the roots or is absorbed, by going through the vessels that are located in the stem.

These parts of the plant will help to carry the water to the plant. The long tubes or roots that are found on a plant are called xylem.

Carbon Dioxide

Carbon dioxide passes through the pores that are in the leaves. Pores are tiny holes and the pores in plants are called stomata.

The carbon dioxide passes through the stomata from the air. The stomata is located in the leaves of the plant.

Breathing” of Plants

We all know that oxygen is a colorless gas that has no odor. This gas is needed in the air for things that are alive to keep on living.

When we breath in and out, we breath in oxygen and we breath out carbon dioxide.

Carbon dioxide is another gas that is colorless and odorless and people and animals’ breath out this gas, whenever we breath.

Even though people breath in oxygen and out carbon dioxide, plants breath carbon dioxide in and they release the oxygen into the atmosphere.

When people and animals’ breath, the carbon dioxide is released into the air.

The plant takes the carbon dioxide and basically recycles it into oxygen which allows humans to breath and plants to make food.

The Process Behind Photosynthesis

Photosynthesis happens inside the leaves of plants. The leaves are made up of cells, super tiny cells and inside the cells are structures that are called chloroplasts.

Chloroplasts are tiny green parts that are found inside the plant cell. The chloroplasts have a chemical that is called chlorophyll.

Chlorophyll is the chemical that gives the plants a green coloring.

In order for photosynthesis to work, the sun is absorbed by the chlorophyll and then the energy from the sun helps the plant to split water molecules into hydrogen and oxygen.

When these molecules are split, oxygen begins to be released into the atmosphere and then the hydrogen and the carbon dioxide that enter and are released into the atmosphere help to form glucose, a sugar that is a food for the plants.

The glucose gives the plant energy and helps it to grow. Even though the plant uses some of the glucose, other parts of it are stored inside of the leaves, fruits or roots of the plants so that it can be used at a later time when it is needed.

Light Dependent Reactions

Photosynthesis can happen in two different stages, the light dependent reaction stage and the Calvin Cycle stage.

With the light dependent reaction stage happens, it can only work if light is present.

When light is present, the thylakoid membrane that is part of the chloroplast reacts to the light and then this energy is converted to a chemical energy.

Calvin Cycle

The Calvin Cycle happens in the stroma, or the pores found in the leaves, and can happen without light.

Photosynthesis Production

Photosynthesis helps plants to produce both food and oxygen.

As we read, the glucose that plants make during photosynthesis is either used to make the plant grow bigger or it is stored in the roots or in the fruit of the plant.

When people eat vegetables that are made through photosynthesis, these vegetables give energy to humans and animals, just like the glucose gives energy to the plant.

Why is Photosynthesis Important?

Photosynthesis is important because there cannot be any living human being or animal without the process of photosynthesis.

Photosynthesis is our energy for growth and many of our natural resources, such as coal or natural gas are made up of animal or plant remains that got their life from photosynthesis and they are giving back life through other resources.

Photosynthesis helps the earth because it helps to make sure that there is a healthy balance that occurs between both carbon dioxide and oxygen.

Without there being a balance, people would not be able to live. Breathing in too much oxygen or carbon dioxide could be deadly to both humans and animals.

Plants absorb the carbon dioxide that is released into the air so that humans and animals do not breath too much of this and then the plants release the perfect amount of oxygen that give us energy and life.

Formula for Photosynthesis

The formula for photosynthesis is:

(6) H2O + (6) CO2 (Light Energy) C6H1206 + (6) O2

The equation says that water and carbon dioxide come together with light energy to make glucose and oxygen.

C02 = Carbon Dioxide

H= Hydrogen

C= Carbon

H2O= Water

O= Oxygen

(Light Energy) = Sunlight

Facts About Photosynthesis:

  • Photosynthesis is defined as the process by which plants and other organisms use sunlight to make energy and the energy is used to make food.
  • An organism that cannot make its own food is called a heterotroph.
  • Chlorophyll is found in different plants and it is also found in some bacteria and in algae. Remember! Chlorophyll gives the plants the green color.
  • An autotroph is something that can make its own food.
  • Chloroplasts are found in the cells of plants.
  • Chloroplasts help to capture energy that helps the plant make food.
  • Another name for water is H2O.
  • Another name for Carbon Dioxide is CO2.
  • There are more chlorophyll in plants than any other pigment.
  • Chlorophyll is found in chloroplasts and can only be seen with a microscope.
  • Chlorophyll is a jelly like substance that is green.
  • Without photosynthesis, there would be no oxygen for humans and animals to breath.
  • Glucose is a sugar that gives energy.
  • Glucose is used by plants as a food source that is mostly stored.
  • When glucose is broken down, it is called respiration.
  • During respiration, glucose is converted into different forms of energy, some being mechanical and some being thermal energy.
  • Plants go through respiration and photosynthesis.
  • Humans only go through respiration.
  • Humans take glucose energy from the plants.

What Did You Learn?

  • What are the three things that are needed in order for photosynthesis to occur? The three things that are needed for photosynthesis are Carbon Dioxide, Water and Sunlight.
  • What are the two things that photosynthesis produces? Photosynthesis produces oxygen and food.
  • What is photosynthesis? Photosynthesis is where plants use sunlight to make food from water and carbon dioxide.
  • What is respiration of a plant? Respiration is when glucose is broken down into different forms of energy.
  • Do humans go through photosynthesis? Humans do not go through photosynthesis. Humans reap the benefits of photosynthesis by using the glucose energy that plants release.
  • What is a sugar that gives energy? Glucose is the sugar that plants make that gives energy. Glucose is stored in the plant and used to help the plants to grow and reproduce.