The word photosynthesis is made up of two parts. Photo means light and synthesis means to put things together. So, photosynthesis is the process by which a plant uses light energy to combine compounds and produce sugars.
Photosynthesis takes place inside plant cells, in small structures called chloroplasts.
Chloroplasts contain a green pigment called chlorophyll. As the plant undergoes photosynthesis, the chlorophyll absorbs sunlight and uses it to convert carbon dioxide and water into glucose and oxygen.
The word equation for photosynthesis is:
Carbon Dioxide + Water → Glucose + Oxygen
In other words, carbon dioxide reacts with water to form glucose and oxygen.
To carry out photosynthesis, plants absorb carbon dioxide from the air through their leaves and water through their roots. Photosynthesis can only occur in the presence of light because light is the source of energy, which comes from the Sun.
The oxygen produced is released into the air through the leaves, where it is used by both plants and animals for respiration.
Photosynthesis helps to maintain carbon dioxide and oxygen levels in the atmosphere. This is because plants absorb carbon dioxide and release oxygen. Photosynthesis is also important for the Earth’s ecosystem because it provides a source of food for animals
Not all plant cells carry out photosynthesis, as it requires the presence of chloroplasts. Chloroplasts are found in the cells of the leaves, stems, and flowers of plants, but not in all plant cells.
Leaves have many adaptations that help them to carry out photosynthesis efficiently. The main adaptations of the leaf are shown in the table below.
|Broad leaves||Provides a large surface area, which allows them to absorb more sunlight and take in more carbon dioxide.|
|Thin structure||Provide a shorter distance for gases, such as oxygen and carbon dioxide, to diffuse in and out of the cells.|
As a result, gases are able to diffuse in and out of the cells more quickly.
|Xylem and phloem tubes||Xylem and phloem tubes transport water and nutrients from the roots to the leaves and help to support the structure of the leaf.|
|Chlorophyll||Helps them to absorb sunlight and carry out photosynthesis.|
|Stomata||Leaves have tiny holes called stomata, which allow them to take in carbon dioxide and release oxygen.|
These adaptations enable leaves to absorb sunlight and carbon dioxide efficiently, both of which are essential for photosynthesis.
Glucose is a type of sugar that is produced by plants during photosynthesis and is an important source of energy. It can be bonded together in different ways to form different carbohydrates, such as cellulose, glycogen, and starch.
The uses of glucose include: