Photosynthesis (Junior Cert Wood Technology): Revision Notes

Photosynthesis

Definitions

1. Photosynthesis:

   • How green plants, like trees, make their own food (sugar) and energy with sunlight.
   • Changes carbon dioxide and water into sugar and oxygen.
   infoNote

   Photosynthesis is essential for the survival of plants and is a key function in the carbon cycle.

2. Chlorophyll:

   • A green stuff needed for photosynthesis.
   • Takes in sunlight and turns it into energy.
   chatImportant

   Chlorophyll is essential for capturing sunlight and is a main cause for the green appearance of plants.

3. Carbon Dioxide:

   • A gas taken from the air.
   • Used in photosynthesis to make sugar.

4. Glucose:

   • A simple sugar made by photosynthesis.
   • Main energy source for the tree.

5. Oxygen:

   • A result of photosynthesis.
   • Released into the air and essential for life.

The Process of Photosynthesis

• Photosynthesis happens mainly in the leaves of trees.
• Step-by-step:
  • Carbon dioxide comes in through small openings in leaves.
  • Roots absorb water, which travels to leaves.
  • Chlorophyll in leaves captures sunlight.
  • Sunlight energy makes chemical reactions that turn carbon dioxide and water into sugar and oxygen.
• The sugar gives energy for the tree to grow and stay healthy.

Diagram:

Chemical Reactions in Photosynthesis

• Photosynthesis turns carbon dioxide and water into sugar and oxygen with sunlight.
• Formula:
  • $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$
  chatImportant

  Correctly balancing the photosynthesis chemical equation is essential for understanding the overall process.

Inputs		Outputs
6 CO2	+	C6H12O6
6 H2O	→	6 O2

Importance of Chlorophyll

• Chlorophyll is key to catching light energy and starting photosynthesis.
• It turns sunlight into energy to make sugar.

Diagram:

Photosynthesis and the Carbon Cycle

• Photosynthesis is key in the carbon cycle.
• Trees take carbon dioxide from the air, cutting greenhouse gases.
• It acts as a carbon store by keeping carbon in trees, reducing gases and helping oxygen production, crucial for life on Earth.

Diagram:

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