Photosynthesis and uses of glucose

Photosynthesis is an important endothermic reaction in which energy is absorbed from the environment and transferred into the chloroplasts of plant cells by light. This energy is used to convert carbon dioxide (CO₂) and water (H₂O) into glucose (C₆H₁₂O₆) and oxygen (O₂).

Energy Transfer in Photosynthesis

• Chemistry: Photosynthesis is an endothermic reaction, meaning it absorbs energy from the environment.

• Physics: During photosynthesis, energy from light is converted into chemical energy stored in the bonds of glucose molecules.

• Biology: Photosynthesis takes place in the chloroplasts of plants and algae.

The word equation for photosynthesis is: 

carbon dioxide + water → glucose + oxygen 

(The word ‘light’ can also be placed above the arrow)

The symbol equation for photosynthesis is:

 CO2 + H2O → O2 + C6H12O6 

(The word ‘light’ can also be placed above the arrow)

The uses of glucose

The Uses of Glucose

The glucose produced during photosynthesis is essential for the plant. It can be used in several ways:

1. Stored as starch: Glucose can be converted into starch, which is an insoluble form of storage made of long, branched chains of glucose molecules.

2. Converted into fats or oils: Glucose can be broken down and rearranged to form fats or oils, which are also used for storage.

3. Making cellulose: Glucose is used to produce cellulose, which strengthens the plant’s cell walls. Cellulose consists of long, unbranched chains of glucose molecules.

4. Synthesising amino acids: Glucose is used to make amino acids, which are essential for protein synthesis. Plants combine glucose with nitrate ions absorbed from the soil to produce proteins, which are needed for growth and for making enzymes.

5. Respiration: Glucose is also used in the respiration process, releasing energy that the plant uses for various functions.

Testing for the products of photosynthesis